Well Operations

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Well Completion and Operations

Well operations Sfax, June 2010

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Well Completion and Operations

Course plan 1. Basic well completion design and practices 2. Formation-wellbore communication, Sand control 3. Downhole completion equipment: • Packer selection and tubing forces • Tubing design and selection: Materials selection, Corrosion and erosion • flow control equipment and subsurface safety valves 4. Wellhead and chokes MMA

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Well Completion and Operations

Course plan 5. Well performance: nodal analysis, inflow and tubing performance 6. Deviated, multiple zone, subsea, horizontal, multilateral and HPHT completion considerations 7. Perforating design 8. Causes and prevention of formation damage 9. Stimulation design considerations 10. Wireline, coiled tubing and Snubbing 11. workover rig operations MMA

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Stimulation • The technique of getting more production from a down hole formation, it may involve acidizing and hydraulic fracturing. • Any process undertaken to enlarge the old channel in the reservoir rock or create new ones

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Well Completion and Operations

Stimulation • Stimulation involve the pumping of fluids down into the formation. It includes • Acidizing by injecting acid in the reservoir formation. • Fracturing by applying enough pressure through a pumped fluid to split the formation apart. • For acid fracturing treatments are designed to create fractures that are simultaneously widened by acid dissolution. MMA

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Well Completion and Operations

Stimulation •Acidizing • A technique used to increase permeability in the reservoir rock immediately around the borehole by injecting acidic fluids. • The process used to clean the walls of the borehole, screens or liners by circulating or injecting acidic fluids.

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Stimulation •Acidizing • Carbonate formations: acid treatments are designed to enhance permeability by dissolving part of the rock matrix. • Sandstone formations: the objective is to squeeze acid into the existing pore spaces of the rock matrix; this improves productivity by removing formation damage and dissolving particles MMA

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Well Completion and Operations

Stimulation •Acidizing The acid job is depending on the characteristics of the reservoir rock and fluids and the configuration of the well and the rock matrix. It includes: • The type of acid to be used, • the chemicals to be added to improve its efficiency, • the volumes to be pumped, • and the pumping pressures to maintain MMA

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Well Completion and Operations

Stimulation •Acidizing • Hydrochloric acid (HCL) was used to acidize limestone and dolomite in the beginning of the 30’s. • In the 40’s a mixture of Hydrochloric acid (HCL) and hydrofluoric (HF) acid called mud-acid was used.

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Stimulation •Acidizing Acids that are commonly used for stimulation are: 1. Hydrochloric acid (HCl) 2. Hydrofluoric acid (HF) 3. Acetic Acid 4. Formic Acid

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Well Completion and Operations

Stimulation •Acidizing 1. hydrochloric acid (HCl) is the most widely used due to its: • high carbonate dissolving ability • low cost. - It dissolves limestone, dolomite and other carbonates. - It reacts with limestone to form water, carbon dioxide and calcium chloride. 2HCI + CaCO3 → CaCl2 + H2O + CO2 MMA

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Well Completion and Operations

Stimulation •Acidizing 1. hydrochloric acid. - Its reaction with dolomite forms water, carbon dioxide, magnesium chloride and calcium chloride. 4HCI + CaMg(CO3)2 → CaCl2 + MgCl2 + 2H2O + 2CO2

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Well Completion and Operations

Stimulation •Acidizing 1. hydrochloric acid. - A solution of 15% HCl by weight is most often used in limestone or dolomite formations, - 10 m3 of a 15 % hydrochloric acid solution dissolves 2.21 t calcium carbonate - 10 m3 of a 15 % hydrochloric acid solution dissolves 2.035 t dolomite MMA

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Well Completion and Operations

Stimulation •Acidizing 2. Hydrofluoric acid (HF) is used on sandstone reservoirs since it reacts with siliceous compounds. - It is employed exclusively in sandstone matrix treatments to dissolve either formation clays or migrated clays

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Well Completion and Operations

Stimulation •Acidizing 2. Hydrofluoric acid (HF) - Due to fast reaction time and precipitants (calcium fluoride) HF acid should never be used in carbonate formations, - For sandstone with low carbonate content, HCL pre-flush is used to avoid the contact of HF acid with carbonates. MMA

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Stimulation •Acidizing 2. Hydrofluoric acid - A mixture of 3% HF and 12% HCl, known as mud acid is used to dissolve clays and remove mud cakes in sandstone reservoirs - mud acid is used exclusively for sandstone reservoirs with little calcium or without calcium. - 10 m3 of 3 % HF acid will dissolve 1.322 t of clay. MMA

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Well Completion and Operations

Stimulation • Acidizing 3. Acetic acid (CH3COOH) is a weakly ionized, slow-reacting organic acid. - Easy to inhibit against corrosion and can usually be left in contact with tubing or casing for days without danger of serious corrosion - 10 m3 of 10 % acetic acid will dissolve about 1.862 t of limestone. - The cost of dissolving a given weight of limestone is greater with acetic acid than with HCl acid. MMA

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Well Completion and Operations

Stimulation • Acidizing 4. Formic acid (HCOOH) is a weaklyionized, slow reacting organic acid. It has similar properties to acetic acid. - It is more difficult to inhibit against corrosion at higher temperatures - It does not have the widespread acceptance and use of acetic acid

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Stimulation • Acidizing 4. Formic acid and Acetic acid are both used in stimulations where their slower reaction time and ease of inhibition is required. On the basis of cost, these acids are 3 to 5 times more expensive than HCl

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Well Completion and Operations

Stimulation • Acidizing Acid additives: • acid can create a number of well problems, and may: • release fines (precipitants) that plug the formation, • form emulsions, • create sludge, and • corrode steel. • Additives are available to correct these and a number of other problems, MMA

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Well Completion and Operations

Stimulation • Acidizing Acid additives: • a variety of chemicals that help the acid work more efficiently: • Inhibitors prevent the acid from attacking the steel tubing and casing at high bottom hole temperatures. • retarders can prevent the acid from spending quickly on the first formation rock it encounters, allowing the acid to be pumped further into the formation, MMA

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Stimulation • Acidizing Acid additives (cont’d) : • Surfactants help prevent acid/oil emulsions from forming and reducing the ability of the fluids to flow. • iron sequestering agents to control the deposits within the formation of the precipitates of acid and iron reaction. • Temporary plugging agents are also added, to divert the acid into different layers of the formation and improve overall permeability. MMA

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Well Completion and Operations

Stimulation • Acidizing • Pumping acid : • Volumes of 50 to 200 gallons of acid per vertical foot of formation are typical for most reservoirs, depending, of course, on the porosity and rock type. • pumping rates range from less than one barrel per minute to more than ten barrels per minute. MMA

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Well Completion and Operations

Stimulation • Fracturing • It consists on pumping under extremely high pressure, a fluid into a cased and perforated wellbore until the hydraulic pressure caused the formation to part. • continuing pumping would force the fluid into the fracture, propagating the fracture farther from the wellbore. • This will open new flow channels in the rock surrounding the fractured well MMA

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Stimulation • Fracturing

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Well Completion and Operations

Stimulation • Fracturing • a fluid (such as diesel fuel, crude oil, dilute hydrochloric acid, water, or kerosene) is pumped through tubing or drill pipe, and squeezed into the reservoir formation at extremely high pressure and high pumping rate • Propping agents are carried in suspension by the fluid into the opened cracks, to keep them open MMA

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Well Completion and Operations

Stimulation • Fracturing • When the pressure is released at the surface, the fracturing fluid returns to the well. The cracks partially close on the pellets, leaving channels for oil to flow around them to the well. • The fracture orientation is dependent upon geologic conditions and most fractures are vertical rather than horizontal

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Stimulation • Fracturing Creating a high-conductivity fracture involves: • selecting the appropriate fluid, additives, and propping agent • determining the optimum volume of material to be pumped • pumping the material at the appropriate rate and pressure MMA

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Well Completion and Operations

Stimulation • Fracturing • The appropriate fluid should have: • the ability to remain in the fracture and not leak off into the formation, • the viscosity necessary to transport the proppant out into the fracture, • the ability to flow back into the well easily after depositing the proppant • Water-based polymer solutions are popular, as are gel led hydrocarbons for water-sensitive formations MMA

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Well Completion and Operations

Stimulation • Fracturing Fracturing fluids: • Oil fluids are cheap and have inherent viscosity which makes them advantageous for relatively low injection rate, shallow to medium depth fracturing. Pressure loss down the casing and safety consideration are often limiting factors

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Stimulation • Fracturing Fracturing fluids: • Gelled water fluids have special advantages due to their higher density and lower friction loss in deeper wells, and where higher injection rates are needed. Where high temperatures are involved reasonable viscosity can be maintained above 250 °F MMA

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Well Completion and Operations

Stimulation • Fracturing Fracturing fluids: • Ultra-high viscosity fluids are costly and temperature sensitive, but can provide wide, highly-conductive fractures needed to stimulate higher permeability zones — or sand carrying capacity needed to prop long fractures in low permeability zones

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Well Completion and Operations

Stimulation • Fracturing Fracturing fluids: • Ultra-high viscosity fluids are costly and temperature sensitive, but can provide wide, highly-conductive fractures needed to stimulate higher permeability zones, or sand carrying capacity needed to prop long fractures in low permeability zones • Emulsion fluids provide moderate viscosity, and good fluid loss and carrying capacity at a reasonable cost MMA

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Stimulation • Fracturing Fracturing fluids: • Alcohol, LPG-C02 and Aerated fluids have limited application due to: • cost, • safety and or • complexity. Usefulness is primarily in gas or low permeability zones where cleanup is paramount MMA

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Well Completion and Operations

Stimulation • Fracturing • A wide variety of additives are available: • to reduce fluid friction in piping, insure compatibility with the formation, prevent fluid loss from the fracture, and control contamination. • Proppant to hold open the fracture

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Well Completion and Operations

Stimulation • Fracturing • The standard proppant used to hold open the fracture is silica sand • In deep formations where fractureclosure stresses are high, sintered bauxite, zirconium oxide, or other highstrength materials are used MMA

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Well Completion and Operations

Stimulation • Acid fracturing • The process of opening cracks in reservoir rock by using a combination of oil and acid under high pressure • Acid-fracturing treatments are designed to create fractures that are simultaneously widened by acid dissolution

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Well Completion and Operations

Rigless operations

• Rigless operations are light operations performed on a well for control, survey, monitoring, repair or improvement and not requiring the use of a rig. • Operations can be carried out under pressure and even without stopping production.

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Well Completion and Operations

Rigless operations

• Usually the work is done inside the tubing without killing the well by means of a lubricator connected to the wellhead. • Operation are performed quickly by using light and highly mobile equipment and 2 to 3 men crew.

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Well Completion and Operations

Rigless operations

Rigless well operations include mainly: • Wireline or slickline operations: running and pulling control devices, pressure monitoring, etc. • Electrical wireline operations: production logs, corrosion survey, reperforating and shut in zones • Coil tubing • Snubbing MMA

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Well Completion and Operations

Rigless operations

Wireline operations

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Well Completion and Operations

Rigless operations

Wireline operations • Are operations performed in a wellbore by use of tools which are run and pulled on slick or braided wireline. • They are simple, quick and economic compared to the other means of intervention in the well. • The main drawbacks are: • The uncertainty of depth (wire stretch) • Limitations in operating tools down hole (no rotation, no circulation and limited tensile) • No direct reading or direct clear indication on surface. MMA

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Rigless operations

Wireline operations • The main wireline services capabilities are: • Running and pulling downhole flow control devices: plugs, chokes, safety valves, gaslift valves, etc. • Running and pulling pressure and temperature gauges and survey along the production string. • Opening and closing circulation devices (tubing \ casing): SSD, ported nipples. MMA

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Well Completion and Operations

Rigless operations

Wireline operations • The main wireline services capabilities are also: • Tubing calibration and cleaning the inside of the production string (scraping). • Collecting downhole solid and fluid samples • Perforating tubing (mechanically) • Fishing of the wireline, tools and scrap MMA

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Well Completion and Operations

Rigless operations

Wireline operations the wire line Any line of wire or cable used for down hole operations. It is supple enough to bend freely and repeatedly without breaking. •There are 3 types: • slick (single-strand line of high tensile steel), usually 0.066" to 0.108" in diameter, • braided (multiple strand line) used for heavier wireline equipment • electrical (including several conductors with metallic braided armor). MMA

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Rigless operations

Wireline operations The wire line • Nominal Breaking Loads: - 0.108” nominal diameter: 1970 lbs (GD316) - 0.125” nominal diameter: 2638 lbs (GD316) • Steel Composition: - GD316 (Austenitic) 12% Ni / 17.5% Cr / 2.5% Moly - 50N (Multiphase) 35% Ni / 20% Cr / 9.8% Moly MMA

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Well Completion and Operations

Rigless operations

Wireline operations The tool string It is a combination of several tools: • The rope socket is connecting the wireline to the string tool

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Well Completion and Operations

Rigless operations

Wireline operations The tool string The tool string should have enough weight to run with supple slick line inside the production string: • Sinker bars or Stems, are round rods used to provide the mass required for lowering the wireline tools in the hole. Available in ¾" to 2-⅞" diameter and 2, 3 and 5 ft length MMA

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Rigless operations

Wireline operations The tool string To accommodate rapid changes in the inclination and help the alignment of the tools : • Knuckle joints are placed just above the run tools.

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Well Completion and Operations

Rigless operations

Wireline operations The tool string To accelerate string movement (release tools, shear pins), jars and accelerators are used to either jar up or jar down. Accelerator Mechanical Jar MMA

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Well Completion and Operations

Rigless operations

Wireline operations the tool string Some times a combined tool is use: • Knuckle jar.

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Rigless operations

Wireline operations The operating tools The operating tools are the tools connected at the bottom end of the wireline string to provide the required action: • running tool: it runs and set mandrels in the corresponding nipples. By jarring the mandrel is set, by continuing jarring the running tool is released MMA

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Well Completion and Operations

Rigless operations

Wireline operations The operating tools • Pulling tool is used to unlock then pull out the mandrel from a nipple It catches the pulling neck of the mandrel by jarring, continuing jarring will unlock the mandrel which will be retrieved. MMA

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Well Completion and Operations

Rigless operations Wireline operations

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Well Completion and Operations

Rigless operations

Wireline operations The operating tools • The kick off tool for the side pocket mandrel

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Well Completion and Operations

Rigless operations

Wireline operations The operating tools • The shifting tool for SSD

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Well Completion and Operations

Rigless operations

Wireline operations the operating tools • Gauge cutter is a hallow cylinder with sharp edge at the bottom side. It is usually run before any other tool to calibrate the tubing and check the profiles depth. It is also used to remove deposit from the tubing. MMA

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Rigless operations

Wireline operations The operating tools • Tubing perforator to make a hole in the tubing for circulation Its punch is activated by jarring,

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Well Completion and Operations

Rigless operations

Wireline operations

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Tubing perforator

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Rigless operations

Wireline operations The operating tools • Impression block has a lead filled block at its base. It is used to get an imprint of the fish top shape in the tubing.

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Rigless operations

Wireline operations the operating tools • Fishing tools: they are run to recover lost material in the hole: • Tools for fishing a broken line:

WL retriever MMA

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Well Completion and Operations

Rigless operations

Wireline operations the operating tools • Fishing tools: they are run to recover lost material in the hole: • Wireline cutter to cut the line at the rope socket level • Tools for fishing rod, stem, MMA

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Well Completion and Operations

Rigless operations

Wireline operations

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Well Completion and Operations

Rigless operations

Wireline operations

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Well Completion and Operations

Rigless operations

Wireline operations

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Well Completion and Operations

Rigless operations

Wireline operations

Bottom blanking plug MMA

Bottom check valve WCO -P2_2010 -V0

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Well Completion and Operations

Rigless operations

Wireline operations Tubing repair with straddle pack-off

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment

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Well Completion and Operations

Rigless operations

Wireline operations

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment The wireline control unit

The wireline reel MMA

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment • The lubricator is a pressure chamber in which the wireline tool string with the operating tools are suspended prior to run in the well. It is composed out of two or three sections. The sections are joined together with quick unions MMA

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Well Completion and Operations

Rigless operations

Wireline operations

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment

• The lubricator and its accessories: The lubricator riser The flange adapter

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment • The top end of the lubricator is packed off by the stuffing box

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Rigless operations

Wireline operations The surface equipment • the stuffing box

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment • The BOP

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Well Completion and Operations

Rigless operations

Wireline operations The surface equipment • The BOP

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Well Completion and Operations

Rigless operations

Electrical wireline operations

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Well Completion and Operations

Rigless operations

Electrical wireline operations • They are performed using a wireline logging company. • They include production logs and some remedial jobs. • Production logs refer to the electrical logs run after putting the well on production Usually they are run with the well alive MMA

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Well Completion and Operations

Rigless operations

Electrical wireline operations • They help to address the following issues: • Mechanical failure in the well: casing, tubing or packer leaks, internal or external corrosion • Fluids movement between zones: behind or inside casing. • Borehole interface efficiency: zones participation in flow rate and type of fluid. • Fluids in the reservoir: fluids saturation, O/W and O/G contacts MMA

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Rigless operations

Electrical wireline operations • Production logs are different combinations from the following: • Casing Collar locator • Temperature gauge • Pressure gauge • Gradiomanometer • Spinner flow meter • Caliper • Cement Evaluation Tool • Gamma ray • Neutron MMA

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Well Completion and Operations

Rigless operations

Electrical wireline operations • Production logging devices are measuring parameters and not giving concrete answers to questions • Often several logging devices along with other field and reservoir data are required to understand the situation. • Experience with log interpretation (mainly production logs) is a key factor for an effective analysis. MMA

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Well Completion and Operations

Rigless operations

Electrical wireline operations • Casing Collar Log (CCL): • shows the casing collars • is used mainly for correlation purpose, • shows major casing defects, mainly parted casing • is run with packers or bridge plugs to avoid setting them in front of a collar.

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Well Completion and Operations

Rigless operations

Electrical wireline operations • Temperature Log • gives the temperature profile along the string and below the tail pipe. • The temperature is affected by heat flow and fluid expansion.

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Well Completion and Operations

Rigless operations

Electrical wireline operations • Gradiomanometer: • is based on pressure measurement at two fixed points. • It is good for identifying gas entry point and locating standing water levels. • Spinner flow meter • is based on propeller movement. • It gives the rotation rate and direction, therefore the fluid rate and direction. MMA

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Well Completion and Operations

Rigless operations

Electrical wireline operations • Multifinger Imaging Tool: • makes highly accurate radial measurements of the internal diameter of tubing and casing strings. • shows tubing wall defects • Multi-frequency electromagnetic Thickness Tool : • Detects metal loss and changes in casing geometry, regardless of casing fluid type MMA

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Well Completion and Operations

Rigless operations

Electrical wireline operations • Remedial jobs: • Through tubing bridge plug: to isolate zones perforations • Re-perforation. • Perforation extension

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Well Completion and Operations

Rigless operations

Coil tubing Hydraulically powered system designed to inject and retrieve a continuous string of tubing MMA

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Well Completion and Operations

Rigless operations

Coil tubing • Continuous steel pipe 1" to 3.5" OD • Yield strengths of 70.000. 80.000. 90.000. 100.000 psi • Relatively thin wall • Finite life due to fatigue cycles (bending).

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Rigless operations

Coil tubing • It is stored on a reel (up to 16,000 feet of coil tubing).

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Well Completion and Operations

Rigless operations

Coil tubing

The basic components of a coiled tubing unit are: 1) 2) 3) 4) 5) 6) 7) 8)

Injector Tubing Guide Arch Service Reel. Power Supply / Prime Mover. Control and Monitoring Equipment. Control Console. Downhole Coiled Tubing Connectors. Well Control Equipment.

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Well Completion and Operations

Rigless operations

Coil tubing 1- Tubing Injector The injector assembly is designed to perform three basic functions: a) to provide the trust required to snub the tubing into the well against pressure or to overcome wellbore friction

b) to control the rate of lowering the tubing into the well under various well conditions. c) to support the full weight of the tubing. MMA

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Rigless operations

Coil tubing 1- Tubing Injector

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Well Completion and Operations

Rigless operations

Coil tubing The coil tubing injector

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Well Completion and Operations

Rigless operations

The coil tubing injector

Coil tubing

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Rigless operations

Coil tubing

Injector Specifications

• Maximum Pulling Force: Is the max.

tensile force that the injector can apply

• Maximum Snubbing Force: Is the max. compressive force the injector can apply

• Maximum Traction: Is the max. axial

force that the injector can apply to pull C.T.

• Maximum Speed : Is the max. rate at

which the injector is capable of deploying tubing into the wellbore (R.I.H) or extracting the tubing out the wellbore.

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Well Completion and Operations

Rigless operations

Coil tubing 2- Tubing Guide Arch • The tubing arch supports the tubing through the 90 °bending radius and guides the C.T. from the reel into the injector chains. MMA

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Well Completion and Operations

Rigless operations

Coil tubing

API Recommendations Tubing Radius Size (in.) (in.) 1-1/4 48 to 72 1-1/2 48 to 72 1-3/4 72 to 96 2 72 to 96 2-3/8 90 to 120 2-7/8 90 to 120 3-1/2 96 to 120 MMA

2- Tubing Guide Arch

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Rigless operations

Coil tubing

3- Service Reel • The services reel serves as the C.T. storage mechanism during transport and as the spooling device during C.T. operations. • The rotation of the service reel is controlled by a hydraulic motor. • During R.I.H. slight back pressure is kept on the reel, this pressure is increased during POOH.

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Well Completion and Operations

Rigless operations

Coil tubing 3- Service Reel

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101

Well Completion and Operations

Rigless operations

Coil tubing 3- Service Reel

MMA

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102

34

OGIM

Well Completion and Operations

Rigless operations

Coil tubing

4- Prime Mover

• In general, the prime mover packages are equipped with diesel engines and multistage hydraulic pumps which are typically rated for pressures of 3,000 psig to 5,000 psig. And in addition, the accumulator package for well control equipment. MMA

OGIM

WCO -P2_2010 -V0

103

Well Completion and Operations

Rigless operations

Coil tubing

MMA

OGIM

4- Prime Mover

WCO -P2_2010 -V0

104

Well Completion and Operations

Rigless operations

Coil tubing 5- Control & Monitoring Equipment Critical Job Parameters A- Load Measurement. B- Depth Measurement. C- Speed Measurement. D- C.T. Inlet Pressure. E- Wellhead Pressure. MMA

WCO -P2_2010 -V0

105

35

OGIM

Well Completion and Operations

Rigless operations

Coil tubing

MMA

OGIM

6- Control Console

WCO -P2_2010 -V0

106

Well Completion and Operations

Rigless operations

Coil tubing 7- Downhole C.T. Tool Connections Non Yielding Connection: - slip type : which requires the use of a slip or grapple-type load ferrule placed on the OD of the tube body. - thread type: connection which is secured to the C.T. with threads. MMA

OGIM

WCO -P2_2010 -V0

107

Well Completion and Operations

Rigless operations

Coil tubing 7- Downhole C.T. Tool Connections • Yielding Connection: - dimple type : which is secured onto the C.T. body through the use of numerous mechanical screws. - Roll-on type: connection which incorporates a machined insert mandrel designed to fit inside the C.T. MMA

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108

36

OGIM

Well Completion and Operations

Rigless operations

Coil tubing 8- Well Control Equipment • Well control equipment components 1) one stripper or annular-type well control component. 2) one blind ram well control component. 3) one shear ram well control component 4) one kill line outlet with isolation valve(s) 5) one slip ram well control component. 6) one pipe ram well control component. MMA

WCO -P2_2010 -V0

OGIM

109

Well Completion and Operations

Rigless operations

Coil tubing 8- Well Control Equipment

MMA

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OGIM

110

Well Completion and Operations

Rigless operations

Coil tubing 8- Well Control Equipment

MMA

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111

37

OGIM

Well Completion and Operations

Rigless operations

Coil tubing

Well Control Stack

• The well control stack is composed of a minimum of four hydraulically-operated rams. The four ram components are equipped (from top down) with, - Blind Rams: are used to seal the wellbore off at the surface when well control is lost. - Shear Rams: are used to mechanically break the C.T. In the event the pipe gets stuck. - Slip Rams : are used to support the weight of the pipe below. - Pipe Rams: are used to isolate the welbore annulus pressure below. MMA

OGIM

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112

Well Completion and Operations

Rigless operations

Coil tubing 8- Well Control Equipment Well Control Stack

MMA

OGIM

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113

Well Completion and Operations

Rigless operations

Coil tubing C.T. Material In the manufacturing of C.T., High Strength low alloy (HSLA) steels are commonly used to achieve the desired; - Weld ability - corrosion resistance - fatigue resistance - mechanical properties MMA

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114

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Rigless operations

Coil tubing HSLA Carbon Steel (by weight percent) Carbon C Manganese Mn Phosphorus P Sulfur S Silicon Si Chromium Cr Nickel Ni Copper Cu Molybdenum Mo Aluminum Cb-V MMA

OGIM

Modified ASTM A606 Type 4

Modified ASTM A607

0.08 - 0.15 0.60 - 0.90 Max 0.03 Max 0.005 0.30 - 0.50 0.45 - 0.70 Max 0.25 Max 0.40 Max 0.21 -

0.08 - 0.17 0.60 - 0.90 max 0.025 max 0.005 0.30 - 0.45 0.40 - 0.60 Max 0.10 Max 0.40 0.08 - 0.15 0.02 - 0.04

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115

Well Completion and Operations

Rigless operations

Coil tubing

Tapered C.T. Strings

• In general, it’s uniform O.D. and variable I.D. to provide enhanced performance in services. • to increase the maximum operating depth of a string use smaller wall thickness. • to enhanced stiffness and buckling resistance use bigger wall thickness The change in the wall thickness should not exceed 0.008” for W.TH. Below 0.110” 0.022” for W.TH. Above 0.110” MMA

OGIM

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116

Well Completion and Operations

Rigless operations

Coil tubing

Corrosion in C.T. Service

Corrosion occurs to the C.T. as a result of exposure to the atmosphere or through metal loss from pumping corrosive fluids. Corrosion Effects: 1) wall thinning and pits >> reduce C.T. strength 2) reduced pressure integrity in collapse and yield pressure. 3) poor seal capability at the stripper and control components. 4) when running C.T. in brine with H2S wellbore environment, it is recommended to add a corrosion inhibitor to the circulating fluids. MMA

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117

39

OGIM

Well Completion and Operations

Rigless operations

Coil tubing C.T. Collapse Pressure Derating • As manufactured coiled tubing will have near 100 % roundness, as it is continually worked onto and off the service reel and over the tubing guide arch the ovality of the pipe typically increases. (Ovality is the major factor in derating tubulars for collapse pressure). • When tubing is subjected to varying degrees of tensile loads, the ability of the pipe to resist collapse is diminished. MMA

OGIM

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118

Well Completion and Operations

Rigless operations

Coil tubing C.T. Collapse Pressure Derating • As applied tensile loads approach the minimum yield strength of the tube, the pipe will undergo permanent strain and “neck-down” at the point of maximum applied stress. Once “necking-down” occures, the pipe looses its principal strength and becomes susceptible to collapse at pressures below the calculated pressure. Also this region will have a reduced burst pressure rating than the remainder of the pipe string.

MMA

OGIM

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119

Well Completion and Operations

Rigless operations

Coil tubing Forces Encountered During C.T. Services there are many forces which affect the behavior of the tubing. - Well pressure Fwp - Tubing drag FD - Tube weight Fw - Stripper element FP - Buoyancy - Chain drive force FC

MMA

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120

40

OGIM

Well Completion and Operations

Rigless operations

Coil tubing Well Control Procedure • The principle of well control is to maintain a safe working condition when performing intervention services. • The kill line outlet on the well control stack should not be used for taking fluid from the wellbore.

MMA

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OGIM

121

Well Completion and Operations

Rigless operations

Coil tubing • Coil tubing unit • The coil tubing unit is rigged up over the wellhead. • The coil tubing is injected through a control head that seals off the coil tubing and makes a pressure-tight connection. • the unit allows continuous circulation while coil tubing is being lowered into the hole MMA

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OGIM

122

Well Completion and Operations

Rigless operations

Coil tubing

MMA

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123

41

OGIM

Well Completion and Operations

Rigless operations

Coil tubing * Pumping Operations Deliver Fluid(s) at required rate and/or pressure at the target depth * Mechanical Operations Deliver tool(s) to the target depth(s) Pull,push or activate a mechanism * Permanent Installations MMA

OGIM

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124

Well Completion and Operations

Rigless operations

Coil tubing • Pumping operations include • Unloading wells with Nitrogen (nitrogen lift) • Stimulating formations (Acidizing) • Removing Fill (Sand) • Removing (Dissolving) organic deposits • Isolating zones with cement • Cutting tubular with fluid (jet cut) • Removing scale hydraulically (jetting) MMA

OGIM

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125

Well Completion and Operations

Rigless operations

Coil tubing • Mechanical Operations include • Logging with CT • Perforating • Fishing • Operating Slide Sleeve • Setting bridge plug or packer • Removing Scale (milling) • Cutting Tubular MMA

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126

42

OGIM

Well Completion and Operations

Rigless operations

Coil tubing • Permanent Installations include • Velocity & Injectivity Strings • CT Completions • Flow lines • Umbilical

MMA

OGIM

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127

Well Completion and Operations

Rigless operations

Coil tubing Operations v Rig up and pressure test equipment as per the recommended guidelines. v Request that the service vendor provide a flow tee to direct the returns flow out of the borehole. Place the flow tee directly below the well control stack. v Install an adjustable choke on the returns line and have a replacement stem available on location. Verify the calibration of the choke with documentation provided. MMA

OGIM

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128

Well Completion and Operations

Rigless operations

Coil tubing Operations v Rig-up full bore pipe tee’s and bull plugs on all “hard-90°” turns in the returns line. This will prevent erosion of the pipe by the sand laden returns. v Be prepared for wash fluid losses to the formation and make provisions for addition wash fluid to be available on location. MMA

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129

43

OGIM

Well Completion and Operations

Rigless operations

Coil tubing Operations

• Tankage on location should be sufficient to capture all returns and solids removed from the well. Plan to have the liquids treated through the production facilitities or sent to an approved disposal site. Solids should be cleaned and dumped, or sent to the proper disposal site. • Run into the borehole with the coiled tubing at an injection rate no faster than 30-40- feet per minute if the top of sand is unknown. If the top of fill has been located in the borehole, run-in rates should not exceed 60-90 feet per minute. MMA

OGIM

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130

Well Completion and Operations

Rigless operations

Coil tubing Operations • Maintain returns throughout the wash program! If the observed returns decrease or cease, pull up the hole with the coiled tubing until returns are reestablished. • Take your time when washing solids out of the well! • When breaking through solids bridges, allow sufficient time to circulate solids out of the hole before continuing downhole. MMA

OGIM

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131

Well Completion and Operations

Rigless operations

Coil tubing Operations • Check tubing drag every 1000’-1200’. • Keep the coiled tubing moving during the wash program to prevent sticking in the solids laden returns. • Monitor the surface pump pressures and returns choke pressures (if used) when circulating up slugs of solids-laden fluid. • When the bottom of the wash section is reached, circulate a minimum of two annular volumes up the borehole prior to extracting the coiled tubing from the well. MMA

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132

44

OGIM

Well Completion and Operations

Rigless operations

Coil tubing Operations • Do not allow the coiled tubing to remain stationary for a period of time longer than 25% of the bottoms-up circulation time when transportation solids up the annulus. • Do not shut down pumps for any reason, unless you are out of the borehole. Wells circulate clean can have sand accumulated up the hole which can have sand accumulated up the hole which can fall back when circulation is interrupted. MMA

OGIM

WCO -P2_2010 -V0

133

Well Completion and Operations

Snubbing unit

MMA

OGIM

WCO -P2_2010 -V0

134

Well Completion and Operations

Snubbing unit

§ Snubbing allows a tubular to be run into well, by means of specialized handling and sealing systems. § It uses tubing-type pipe lengths run in hole and made up to each other by conventional threaded connections. § Tubing string is outfitted with a check valve on the bottom end

MMA

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135

45

OGIM

Well Completion and Operations

Snubbing unit

• Hydraulic units are commonly used with double acting jacks equipped with two systems of slips, one stationary and the other mobile. • The mobile system connected to the jack movement, usually consists of one set of single acting slips (traveling slips). MMA

OGIM

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Well Completion and Operations

Snubbing unit

• The stationary system of slips consists of two sets of opposing slips that keep the pipe in place whatever the phase. • It is located below the low position of the traveling slips. MMA

OGIM

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137

Well Completion and Operations

Snubbing unit

• the operation of pushing the pipe into the well is said snubbing phase (or to be in the snub or the light pipe phase). • the operation when the pipe has to be held up, is said stripping phase (or to be in the strip or the heavy pipe phase).

MMA

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138

46

OGIM

Well Completion and Operations

Snubbing unit

• The traveling slips closed and the stationary ones open, the pipe can be tripped over a length corresponding to the stroke of the jacks. • To bring the jack back to its original position, close the stationary slips and open the traveling slips. • After the traveling slips have been closed again and the stationary slips have been opened the operation can continue. MMA

OGIM

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139

Well Completion and Operations

Snubbing unit

Snub Phase Running In Sequence

MMA

OGIM

WCO -P2_2010 -V0

140

Well Completion and Operations

Snubbing unit

• Specifications • Diameter of the snubbing pipe: 3 1/2" and up to 7 5/8" are possible. • Hoisting capacity in the strip phase 340,000 lb • In the snub phase capacity is usually half that of the strip phase due to jack design.

MMA

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141

47

OGIM

Well Completion and Operations

Snubbing unit

MMA

WCO -P2_2010 -V0

OGIM

142

Well Completion and Operations

Snubbing unit

• Rotary table can be added to the unit, usually at the mobile slips. • Long stroke units consist of a mast with a traveling block, guided by rails and driven by cables actuated by one or two long stroke jacks. • Short stroke units usually have 4 jacks or one concentric jack, and the traveling slips are directly connected to the upper end of the jacks. MMA

WCO -P2_2010 -V0

OGIM

143

Well Completion and Operations

Snubbing unit

Long stroke unit

MMA

WCO -P2_2010 -V0

144

48

OGIM

Well Completion and Operations

Snubbing unit

Short stroke unit

MMA

OGIM

WCO -P2_2010 -V0

145

Well Completion and Operations

Snubbing unit

• Operations • Clean out hard fill and scale that require weight on the tool and rotation. • Spot cement plugs. • Perform some fishing jobs.

MMA

OGIM

WCO -P2_2010 -V0

146

Well Completion and Operations

Snubbing unit

• Snubbing unit offers better flow capacity, breaking load and rotation capacity and it is also able to put weight on the down hole tool. • Tripping takes longer because the lengths of pipe have to be screwed together. • Operating this type of unit requires specialized personnel usually consisting of a head of unit and three or four people per shift. MMA

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147

49

OGIM

Well Completion and Operations

Workover operations • Killing the well and workover fluids • Pulling out completion • Tubing puncher and tubing cutter • Fishing tools • Milling tools

MMA

OGIM

WCO -P2_2010 -V0

148

Well Completion and Operations

Workover operations

What is workover? • Re-entry into a completed well for modification or repair work • Usually it is a heavy work requiring the use of a workover rig. • It requires killing the well and pulling out the completion string

MMA

OGIM

WCO -P2_2010 -V0

149

Well Completion and Operations

Workover operations

Main reasons to workover a well • Repair of reservoir or completion string by mechanical means. • Performance / Enhancement opening new zones or modifying lift.

MMA

WCO -P2_2010 -V0

150

50

OGIM

Well Completion and Operations

Workover operations

Preparing the well for workover • Killing the well: is pumping into the well a fluid that prevent the well from flowing. • Whenever possible, to do it before moving in the rig

MMA

OGIM

WCO -P2_2010 -V0

151

Well Completion and Operations

Workover operations

Preparing the well for workover • Killing fluid • Use a clean, solid free fluid to kill the well • The killing fluid hydrostatic pressure should be greater than reservoir pressure. • It should be compatible with reservoir effluent MMA

OGIM

WCO -P2_2010 -V0

152

Well Completion and Operations

Workover operations

Preparing the well for workover • Methods of well killing • Bullheading: squeezing the effluent in the tubing into the formation by pumping a fluid into the tubing. • Circulation: • Through a coil tubing run in the tubing. • Tubing to casing by opening SSD (if available), punching the tubing or after unsetting the packer or cutting the tubing MMA

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153

51

OGIM

Well Completion and Operations

Workover operations

Well Kill Procedure 1) Bull head kill fluid from surface A- mix and pump non-damaging viscous pill or bridging agent. B- follow the pill with kill fluid.

MMA

OGIM

WCO -P2_2010 -V0

154

Well Completion and Operations

Workover operations

Well Kill Procedure 2) Circulation kill assisted with C.T. A- place the end of the C.T. below the source of pressure. B- spot a bridging agent across the interval of the pressure source. C- circulate kill weight fluid to surface 1½ annular volume. D- S.I. the well for 30 min., break circulation while POOH. MMA

OGIM

WCO -P2_2010 -V0

155

Well Completion and Operations

Workover operations

Preparing the well for workover • Put the well under safe conditions: • Close the SSSV • Set if deemed necessary a plug below the communication point tubing \ casing if available. Otherwise set a check valve • Set a BPV in the tubing hanger. • Disconnect the flow line and any remote control device MMA

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156

52

OGIM

Well Completion and Operations

Workover operations

• BPV

MMA

WCO -P2_2010 -V0

OGIM

157

Well Completion and Operations

Workover operations

The workover rig • Usually it is a light drilling rig with: • Reduced mud storage capacity. • Light mud fabrication and handling capability. • Limited hoisting capacity (usually two times the weight of a 3-½” drill pipe string up to the bottom of the well). • It should be easy to move and easy to install MMA

WCO -P2_2010 -V0

OGIM

158

Well Completion and Operations

Workover operations

Truck Mounted Rig

The workover rig

MMA

WCO -P2_2010 -V0

159

Source: Western Gas 159

53

OGIM

Well Completion and Operations

Workover operations

MMA

OGIM

WCO -P2_2010 -V0

160 160

Well Completion and Operations

Workover operations

The workover rig • For artificial lifted well which may need frequent replacement of downhole equipment (ESP, PCP, Sucker rod pumps) a pulling hoist is often used. • The well pulling hoist is a hoisting unit without any pumping or rotation capability

MMA

OGIM

WCO -P2_2010 -V0

161

Well Completion and Operations

Workover operations

Installing the workover rig • A special care to be given to the wellhead to avoid its damage or destruction while : • Moving heavy loads • Installing the substructure above the well head • Rigging up the mast.

MMA

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162

54

OGIM

Well Completion and Operations

Workover operations

• Removing the Christmas tree • To kill the well (if not done before moving in the rig) and observe the well for pressure or fluid movement. • If well stable with no pressure (tubing and casing) unscrew the bolts of the Christmas tree bottom flange. • Remove the Christmas tree • install the BOP's MMA

OGIM

WCO -P2_2010 -V0

163

Well Completion and Operations

Workover operations

• Preparation to pull out the completion string • Prepare on the rig floor the appropriate handling tools for the string to pull out: slips, tongs, thread protectors, etc. • Have also a valve and a circulating head with the appropriate connections. • Have on the rig site all the equipment required during the following few days. • Prepare this equipment: unpacking, measurement, etc. MMA

OGIM

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164

Well Completion and Operations

Workover operations

• Pulling out the completion string • Make up one tubing joint (or two if required) to the tubing hanger. • Unscrew the lock screws • Pull the tubing hanger from its housing carefully confirming that none of the lock screws is not completely retrieved. • Apply the appropriate tension (or rotation) to unset the packer (or release the anchor from the permanent packer ) MMA

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165

55

OGIM

Well Completion and Operations

Workover operations

• Pulling out the completion string • In case of failure to unset the packer (or to release the locator) consider to cut the tubing. • Circulate out carefully any gas and crude oil usually trapped below the packer. • replace the killing fluid with the workover fluid. • Pull out and lay down the completion string components. MMA

OGIM

WCO -P2_2010 -V0

166

Well Completion and Operations

Workover operations

Workover fluid • Types of fluids • Oil • Clear water • Brines (Sodium Chloride, Calcium Chloride, Potassium chloride) • Oil & water emulsions • Fluid additives • Acid soluble (CaCO3) weighting material • Polymers MMA

OGIM

WCO -P2_2010 -V0

167

Well Completion and Operations

Workover operations

• Workover operation • Pulling out the completion string : • milling out the permanent packer packer mill out tool

MMA

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168

56

OGIM

Well Completion and Operations

Workover operations

• Workover operation • Pulling out the completion string : • milling out the permanent packer packer milling and retrieving tool MMA

OGIM

WCO -P2_2010 -V0

169

Well Completion and Operations

Workover operations

During the workover a lot of planned (or often unplanned) actions will be performed. They include mainly: • Perforating the tubing, using wireline perforator, or electrical wireline puncher. It is required to establish (or re-establish) circulation between tubing and casing. • Releasing a stuck pipe: failure to unset a retrievable packer, failure to release from a permanent packer, restriction in the casing (casing collapse, junk dropped from surface in the annulus, etc.) MMA

OGIM

WCO -P2_2010 -V0

170

Well Completion and Operations

Workover operations

During the workover a lot of planned (or often unplanned) actions will be performed. They include mainly: • Perforating the tubing • Releasing a stuck pipe • Milling • Recovering free junk • Repairing a damaged casing. • Cement remedial jobs • Side tracking a hole MMA

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171

57

OGIM

Well Completion and Operations

Workover operations Releasing a stuck pipe: • The first action is to locate the stuck point. • By pulling on the string and measuring we can find the stuck point using the following formula

where

L = ΔL x E x a / (F x 12)

L: Length, in ft. ΔL: stretch, in inches F: pull force, in lbs. E: modulus of elasticity, in psi (for steel E = 30 000 psi) A: cross-sectional area (wall area), in square inches MMA

OGIM

WCO -P2_2010 -V0

172

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • The stuck point could be also located using the free point indicator. • Free point indicator is a device run on electrical wireline inside the fishing string to locate the area where a fish is stuck. • When the string is pulled and turned, the electromagnetic fields of free pipe and stuck pipe differ. The free-point indicator is able to distinguish these differences, which are registered on a metering device at the surface. MMA

OGIM

WCO -P2_2010 -V0

173

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • Back off is the procedure of applying left-hand torque to a pipe string while firing a shot of a cord explosive to unscrew the pipe at a selected threaded joint above the stuck point. The explosion produces vibration that partially unscrews the threads. MMA

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174

58

OGIM

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • Left hand unscrewing using a left hand string or a reversing tool. • washing over: using a wash over shoe and wash over pipe to clean or mill around the stuck pipe, or to mill out the slips of a bridge plug, packer, cement retainer.

MMA

OGIM

WCO -P2_2010 -V0

175

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • Washing over: • Washover is drill out, wash out and circulate out cement, formation, fill, or other debris around a fish • Washover shoe and washover pipe (or washpipe) are used for that. MMA

OGIM

WCO -P2_2010 -V0

176

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • Washing over: • Washpipe is large pipe with ID large enough to go over the fish, with clearance for circulation, and OD sufficient for circulation and prevention of over-torquing while rotating in the hole or casing. MMA

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177

59

OGIM

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • Pipe cutter: there are different types: • Chemical cutter is run with electrical wireline. It is giving the cleanest cut with no risk for casing.

MMA

OGIM

WCO -P2_2010 -V0

178

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • Pipe cutter: there are different types: • Chemical cutter • The explosive cutter is giving a rough cut with risks for casing mainly if the tubing is aside. • Hydraulic cutter is run with coil tubing (jet cutting or blade cutter with hydraulic motor). MMA

OGIM

WCO -P2_2010 -V0

179

Well Completion and Operations

Workover operations

Releasing a stuck pipe: • Pipe cutter: • Chemical cutter • The explosive cutter • Hydraulic cutter • Mechanical cutter run with drill pipe suitable for casing cut only.

MMA

WCO -P2_2010 -V0

180

60

OGIM

Well Completion and Operations

Workover operations

Free junk fishing: • Recovering junk from the hole: Making special runs to recover junk fishing magnet WL junk catcher MMA

WCO -P2_2010 -V0

OGIM

181

Well Completion and Operations

Workover operations

MMA

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OGIM

182

Well Completion and Operations

Workover operations

• Fishing Tools : • to catch fish from outside

Die collar

overshot MMA

WCO -P2_2010 -V0

183

61

OGIM

Well Completion and Operations

Workover operations

• Fishing Tools : • The overshot

MMA

OGIM

WCO -P2_2010 -V0

184

Well Completion and Operations

Workover operations

MMA

OGIM

WCO -P2_2010 -V0

185

Well Completion and Operations

Workover operations

• Fishing Tools : • to catch fish from inside • Taper tap • Releasing spear

MMA

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186

62

OGIM

Well Completion and Operations

Workover operations

• Fishing Tools : • to fish a cable

MMA

OGIM

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187

Well Completion and Operations

Workover operations

• Recovering free junk : Recovering while milling

MMA

OGIM

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188

Well Completion and Operations

Workover operations

Milling: • using a mill, a downhole tool with rough, sharp, extremely hard cutting surfaces for removing metal by grinding or cutting. • Mills are run on drill pipe to grind up debris in the hole, remove stuck portions of string or sections of casing for sidetracking, and ream out tight spots in the casing. • They are called junk mills, reaming mills, and so forth, depending on what use they have. MMA

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189

63

OGIM

Well Completion and Operations

Workover operations

Mills:

MMA

OGIM

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190

Well Completion and Operations

Workover operations

Milling: • Milling a section of a casing to initiate deviation or side track.

K-mill

MMA

OGIM

WCO -P2_2010 -V0

191

Well Completion and Operations

Workover operations

Other tools that we find in a fishing string or a milling string: • Hydraulic or mechanical jars. • Safety joints.

MMA

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192

64

OGIM

Well Completion and Operations

Workover operations Casing swage mandrel

Casing repair

Casing roller MMA

OGIM

WCO -P2_2010 -V0

193

Well Completion and Operations

Workover operations

Casing repair: • A casing patch is a thin walled steel liner, which tightly conforms against the inside of the casing, with the intent of permanently sealing off any type of leak. • The standard patch restricts the I.D. of the casing by 0.300". A heavier patch is also available in casing sizes 7" and larger with a 0.480 I.D. restriction. MMA

OGIM

WCO -P2_2010 -V0

194

Well Completion and Operations

Workover operations

Casing repair: • casing patch with the relevant tool

MMA

WCO -P2_2010 -V0

195

65

OGIM

Well Completion and Operations

Workover operations

• Remedial cement job is performed for the following reasons: • Shut off unwanted gas production • Shut off water production • Eliminate flow between formations behind pipe (cross flow) • Repair casing leaks and damaged casing • Isolate thief zones • Shut off annular gas flows to control annulus pressure • Abandon depleted formations MMA

OGIM

WCO -P2_2010 -V0

196

Well Completion and Operations

Workover operations

Remedial cement job • Repair inadequate cement bond (already seen in Drilling course) • Cement circulation behind casing • Cement squeeze

MMA

OGIM

WCO -P2_2010 -V0

197

Well Completion and Operations

Workover operations

Remedial cement job • Repair inadequate cement bond: Circulating cement behind casing

MMA

WCO -P2_2010 -V0

198

66

OGIM

Well Completion and Operations

Workover operations

Remedial cement job • Repair inadequate cement bond: Squeezing cement behind casing

MMA

OGIM

WCO -P2_2010 -V0

199

Well Completion and Operations

Workover operations

Remedial cement job • Squeezing cement behind casing

MMA

OGIM

WCO -P2_2010 -V0

200

Well Completion and Operations

Workover operations

Remedial cement job • Perforations squeeze

MMA

WCO -P2_2010 -V0

201

67

OGIM

Well Completion and Operations MAJOR WORKOVERS RECOMPLETIONS

REPAIRS REMEDIAL CEMENTING

UPHOLE

SSSV REPAIRS

DEEPEN

CASING AND TUBING LEAK REPAIR

SIDETRACK

FISHING NEW TUBING REPLACEMENT MMA

WCO -P2_2010 -V0

CONVERT TO INJECTOR

202

68