11 cementing

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Oil & Gas WellCementation


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Cementation

Oil Well cementing is the process of mixing aslurry of cement and water and displacing itdown the casing, tubing or drill pipe to a prespecied point in the well

Primary cementingThe cementing taes place soon after thelowering of casing is called primary cementation!

"econdary cementing

#ny other operations where cement is pumpedin a well either during drilling operation or inproduction phase


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Primary Cementation

Why we need to pump cement in a well$ #n oil%gas well is completed in stages!

ach stage is secured %completed bylowering a suitable si'e steel pipe (casing)!

The casing pipes are held in its position byan ade*uate length of cement bondbetween pipe and annulus!

Cement is mixed with water to form acement slurry of desired density andpumped into the pipe and displaced in theannulus between casing and open hole!


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+ain unctions

-ond and support the casing

Protect the casing from corrosion!

Protect the casing from shoc loads

"ealing.o/ problematic 'ones!

0estrict 1uid mo2ement between formations


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3iagram


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Primary Cementing

Techni*ues4! "ingle stage cementation

5! +ulti stage cementation


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"ingle "tage Cementing

6t is the +ost common techni*ue

7ormally accomplished by pumping one batch ofcement down the casing between two rubber plugs!

The bottom plug is placed in the casing, followed bycement slurry!

When the batch of cement has been pumped into

the casing, a top plug is released!

The top plug is pumped down until it lands on thetop of 1oat collar, thus completing the cement 8ob!


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"tage Cementation9

0easons 3own hole formations unable to support

hydrostatic pressure exerted by a longcolumn of cement

To cement wells ha2ing two or more'ones of interest separated by longinter2als

:imitations of cementing e*uipments Cementing of high pressure gas 'ones &

water producing hori'ons!


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"econdary Cementation

#ny Cementing operation other thanPrimary Cementing Operation (Casing%:iner Cementation) is referred to as

;"econdary Cementation

11 cementing

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