Primary Cementing: Module Cmt101 June 2000

Primary Cementing Module CMT101 June 2000

Primary Cementing The placement of a cementicious material into the annulus between casing and open hole to :

 Provide zonal isolation  Support axial load of casing strings and strings

to be run later  Provide casing support and protection  Support the borehole

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Types of Casings  Conductor  Surface  Intermediate  Production  Liner

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Conductor  Purpose 

Prevents washing out under the rig



Provides elevation for flow nipple

 Common sizes and depths:

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

30” - 20” Welded



20” - 16” Threaded



30’ - 200’ (< 100’ common)

Conductor  Other Remarks:  Plugs not used  Careful pumping practices  Large excess required  Thru-drill pipe cementing common  BOP’s not unusually connected  Common Cements 

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Accelerated Neat

Thru-Drill Pipe Cementing  Key Points:  Cement contamination  Channelling  Displacement  Pump until cement to surface

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Outside Cementing  Purpose 

Bring cement to surface

 Macaroni tubing used  Max. depth 250-300 ft  High friction pressures  Non-standard connections

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Tubing moved during job

Surface Purposes:  Protects surface fresh water formations  Cases off unconsolidated or lost circulation areas  Supports subsequent casing strings  Provides primary pressure control (BOP support)  Common sizes and depths:

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

20” - 9 5/8” threaded



100’ - 3000’ (or more)

Surface Cementing  Excess of 100% plus not uncommon  Recommend thru-drill pipe method to save 

Cement



Rig time

 Common cements:

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

Lead light weight slurries with high yields



Neat tail slurries with good compressive strength



Reduce WOC to a minimum with accelerators

Intermediate Purposes:  Separates hole into workable sections 

Lost Circulation



Salt Section



Overpressured Zones



Heaving Shales

 Common sizes and depths:

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

13 3/8”, 10 3/4”, 9 5/8”



3000’ to 10,000’

Intermediate Casings  Cemented to surface or to previous casing shoe  Two stage jobs common  Plugs, casing equipment, casing accessories usual  Good cementing practices are required  Large cement volumes  Common Cements:  Typically

filler slurries followed by high compressive tail  Specialised (light, heavy, salt - saturated, etc)

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Two Stage Cementing Key Points:  Separation and

isolation of zones

2nd Stage

Stage Collar

 Reduces

hydrostatic  Can leave zone in

the annulus uncemented (cement at TD and surface) 13

1st Stage

Production Purposes:  Isolates the pay zone from other formations and the fluids in them.  Protective housing for production equipment. 

Subsurface artificial lift



Multiple zone completion

 Screens for sand control  Covers worn or damaged intermediate string.  Common sizes: 

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4 1/2”, 5”, 7”, & 9 5/8”

Key Points:

Liners

 Requires less casing  Deeper wells

Drill pipe Wiper Plug

 Small annular clearance  Specialized equipment Running Tool Shear Pin

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Liner Hanger Liner Wiper Plug

Job Procedures  Pre Job:  Check  Rig

calculations with co-man

up  Stem 1 on equipment  Check materials  Safety and organization meeting  Prepare mix fluids, spacers and washes

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Job Procedures The Job:  Test

lines  Load plugs  Pump Washes / Spacers  Drop bottom plug  Mix and pump cement  Drop top plug  Displace  Bump plug and check returns 20

Job Procedures Post Job:  Wash

up  Rig down  Stem equipment  Paper work

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