Ihs Welltest - Fundamental Complete Material

Information | Analytics | Expertise

IHS WELLTEST Software Training Course

© 2014 IHS

Scope of Software Training • Data Preparation and QC:

• Varying Wellbore Storage

• Data importing

• Homogenous Wellbore Storage

• Gauge comparison and synchronization

• Changing in Wellbore Storage

• Time, rate, and pressure editing • Filtering data for analysis • Entering fluid (PVT) and reservoir properties

• Analysis Workflow for: • Standard buildup/Drawdown (c) • Injection/Fall off Test (u) • Mini Frac (u) • Perforation Inflow (PITA) (u) • Perforation Injection Analysis (u) © 2015 IHS

• Boundary • Fractured Reservoir • Horizontal Well • Partial Penetration • Numerical Analysis • Deconvolution

Tutorial#1: Data Preparation and Standard Workflow • Focusing On: • Data importing • Gauge comparison and synchronization • Time, rate, and pressure editing • Filtering data for analysis • Entering fluid (PVT) and reservoir properties • Performing analysis • Varying wellbore storage

© 2015 IHS

Wellbore Storage • Two Types of Wellbore Storage:

• Dimensionless form:

• Fluid filled: wellbore full with fluid (liquid or gas)get compressed.

• Changing Fluid level: Liquid+gasLiquid level increased

• Changing wellbore storage occur when: • Change in fluid compressibility in wellbore • Phase redistribution / fluid segregation

• Both Types are constant value

© 2015 IHS

• Change in type of storage from a changing liquid level to a liquid filled wellbore

Wellbore Storage • When wellbore storage is changing, there will be indication of anomalous pressure which are deviated from unit slope. • Approach to fit the anomalous pressure is proposed by Fair and Hageman

© 2015 IHS

Tutorial#2: Changing Wellbore Storage • Focusing On: • Trying to utilize the effect of ‘Changing Wellbore Storage’ in the software to match with the real data.

© 2015 IHS

Flow Regime Categories

Wellbore Configuration

Early Time

Middle Time

Transition

Late Time

Vertical Wells

Wellbore Storage

Radial

Single No-Flow Boundary

Pseudo-Steady State

Linear Channel

Steady State

Linear Channel

Pseudo-Steady State

Linear Fracture Bilinear Spherical Horizontal Unstimulated

Wellbore Storage

Horizontal Radial

Vertical Radial Steady State Linear Horizontal Horizontal Multifrac

Wellbore Storage

Compound Linear

Pseudo-Steady State

Vertical Radial Linear Fracture

© 2015 IHS

Steady State

7

Vertical Well – Typical Flow Regimes Transient Radial Flow

Linear Fracture Flow

Long Narrow Reservoir – Linear Channel Flow

© 2015 IHS

8

Horizontal Well – Typical Flow Regimes

© 2015 IHS

9

Conventional Modeling in IHS-WellTest Model

Support

Vertical

• • • • • • • •

Vertical Well Well at any location inside reservoir Rectangular shape reservoir Support infinite acting Homogenous Dual porosity No flow boundary Constant pressure boundary

Horizontal

• • • • • • • • • •

Horizontal Well Horizontal section may be at any location in the reservoir Rectangular shape reservoir Anisotropic heterogeneity Dual porosity Infinite acting No flow boundary Constant pressure boundary Modeling well near sealing fault Constant pressure boundary near intersecting fault

© 2015 IHS

Conventional Models in IHS-WellTest Model

Support

Partial Penetration

•

Is Vertical Model where reservoir is partially penetrated / partially connected to wellbore

Composite

• • • • • •

Vertical well Unlimited composite zones Homogenous Dual porosity Change in heterogeneities Naturally fracture reservoir with varying fracture distribution

Fracture with Boundary

•

Vertical well intercepted by infinite conductivity vertical fracture Rectangular reservoir Homogenous Dual porosity Well maybe at any location within reservoir Infinite acting No flow boundary Constant pressure boundary Well near sealing fault Constant pressure boundary near intersecting faults

• • • • • • • • •

© 2015 IHS

Conventional Models in IHS-WellTest Model

Support

Finite Conductivity Fracture

• • •

Vertical well intercepted by finite-conductivity vertical fracture Cylindrical reservoir Infinite acting or No flow boundary

Leaky Fault

• • • • • •

•

Transient flow Well located near leaky fault (finite-conductivity) Infinite acting Two zone composite reservoir – infinite acting Account transient flow within / inside fault The fault characterized in two parameters: • FCD (dimensionless fracture conductivity) • s fault (skin across the fault) No flow boundary by setting FCD = 0 and s fault >>

• • •

Partial Penetrated Model with Anisotropic Well near sealing fault Constant pressure boundary near intersecting faults

Partial Penetration Anisotropic

© 2015 IHS

Conventional Models in IHS-WellTest Model

Support

Fully Penetrating Anisotropic

•

Same as Partial Penetrating Anisotropic model but reservoir is fully penetrated

Multi Layer Rectangular

• • • • • • •

Vertical Well Multi Layer with identical reservoir properties Well may be at any location within EACH layer Infinite acting or no flow or constant pressure boundary Well near a sealing fault Constant pressure boundary near intersecting faults Dual porosity

Multi Layer Cylindrical

•

Same as ‘Multi Layer Rectangular’ Model with cylindrical reservoir

Multi Layer Cylindrical with Unequal Pi

•

Same as ‘Multi Layer Cylindrical’ but with unequal Pi

Slanted

• • • • • • •

Slanted well Rectangular shape reservoir Anisotropic Dual porosity Infinite acting or no flow or constant pressure boundary Well near sealing fault Constant pressure boundary near intersecting faults

© 2015 IHS

Unconventional Model in IHS-WellTest • Minifrac • Work similar with conventional analysis

• PITA • Vertical well • Infinite Acting reservoir; Homogenous • Not support changing wellbore storage; dual porosity; interference test

• Slug • Assume infinite acting reservoir; Homogenous • Not support changing wellbore storage; dual porosity; interference test

• CCT • Same as PITA capability with additional changing of wellbore storage © 2015 IHS

Dual Porosity • Naturally fractured reservoir has two distinct properties, in matrix and in fracture. • Consist of irregular fractures but generally can be represented by homogenous dual porosity system.

© 2015 IHS

Dual Porosity • Dual Porosity is characterized by two parameters: • Interporosity flow coefficient () • Storativity ()

© 2015 IHS

• Storativity is time separation between the two straight line in log cycle.

Dual Porosity • Derivative implication on lambda and omega is as follow:

• Important note: apparent skin in dual porosity concept should be taken from second semi-log straight line

© 2015 IHS

Tutorial#3: Dual Porosity • Focusing on: • Performing Diagnostic and Analysis using Dual Porosity option • Comparing if analysis is done without dual porosity option

© 2015 IHS

Hydraulic Fractured Reservoir • Fracture Conductivity, Pressure drop in the fracture during production period. • Dimensionless Fracture Conductivity, FCD: • Infinite: if the pressure drop is zero in the fracture during production, FCD>100 or flow capacity (kf x wf) > 10,000 mDft • Yield only Linear flow regime in the fracture

• Finite: if the pressure drop is > 0 in the fracture during production, FCD<100 or flow capacity (kf x wf) < 10,000 mDft • Recognized by the present of Bi-Linear flow regime (1/4 slope)

© 2015 IHS

Hydraulic Fractured Reservoir • Flow regime in the Hydraulically fractured reservoir: • Linear Flow in the fracture (Followed with Bi-Linear flow for finite conductivity fracture type) • Linear flow from formation to fracture along the fracture length • Elliptical flow regime • Radial flow

• Two Models applicable: • Fracture with Boundary Model • Finite Conductivity Fracture Model

© 2015 IHS

Hydraulic Fractured Reservoir

Only Linear flow exist

© 2015 IHS

Bi-Linear flow exist

Tutorial#4: Hydraulic Fractured Reservoir • Focusing on: • Determining all possible flow regimes • Determining if the fracture has finite or infinite conductivity by matching the ¼ slope of bilinear flow to get the FCD value. • Choosing appropriate fracture model (infinite or finite fracture model) • History matching to get the fracture half length, permeability, choked-fracture skin, skin apparent

© 2015 IHS

Horizontal Well

© 2015 IHS

Tutorial#5: Horizontal Well • Focusing on: • Determining Flow regimes • Performing horizontal modeling to get reservoir properties and boundary model.

© 2015 IHS

Partial Penetraion

h

© 2015 IHS

h top h perf

Tutorial#6: Partial Penetration – Test Design • Focusing on • Design well testing for partial penetration reservoir with given data • Compare the TD curve if the partial penetration data is changed • Determine the presence of Spherical flow regime

© 2015 IHS

Minifrac • Low permeability formation need reservoir properties from well test analysis before performing fracturing job. • Performing conventional well testing in low perm formation will take extensive time to get stabilize • Minifrac become option • Minifrac: • Is an injection fall-off diagnostic test • Intent is to break down formation to create short fracture • To observe the closure of fracture system created during the falloff period.

© 2015 IHS

Minifrac • Key results:

• Minifrac Technicques:

• Fracture closure pressure (pc)

• PCA (Pre Closure Analysis)

• Instantaneous shut-in pressure (ISIP)

• ACA (After Closure Analysis)

• ISIP gradient

• Nolte

• Net Fracture Pressure (Δpnet)

• Soliman/Craig

• Fluid efficiency • Formation leakoff characteristics and fluid loss coefficients • Formation permeability (k) • Reservoir pressure (pi)

© 2015 IHS

• Modeling

Minifrac • Key Result form Minifrac Test: • Fracture closure pressure (pc) • Instantaneous shut-in pressure (ISIP) • ISIP gradient • Net Fracture Pressure (Δpnet) • Fluid efficiency • Formation leakoff characteristics and fluid loss coefficients. • Formation permeability (k) • Reservoir pressure (pi)

© 2015 IHS

Normal

Pressure Dependend

Transverse Storage

Fracture tip extention

© 2015 IHS

Tutorial#7: Minifrac • Focusing on: • Pre Closure Analysis • After Closure Analysis • Modeling

© 2015 IHS

Deconvolution

© 2015 IHS

Deconvolution • Classical Method

• Modern Method

• Unit Rate Function

• Modern Method (Indirect)

• Convolution (Superposition)

• Concept

• Deconvolution (Direct)

• Strength and Witness

• Limitation

• Comparison with Modeling

© 2015 IHS

Deconvolution – Unit Rate Function (Pu)

© 2015 IHS

Deconvolution – Unit Rate (Pu)

• The Type Curve and Derivative • Fundamental of Well Testing Interpretation • Flow Regime identification • Reservoir description • Pressure Behavior for constant rate © 2015 IHS

Deconvolution – Concept of Superposition(Convolution)

© 2015 IHS

Deconvolution

© 2015 IHS