Calculate Cement (Oil Well Cement) Volume Required

Cement volume calculation is based on annular capacity multiplied by length of cement as per cement program. This topic will demonstrate you how to determine cement volume as per specification and displace volume. After reading and understanding the concept, you will be able to apply to your cement job.

The knowledge required: annular capacity and inner capacity of cylindical object

 

Well information:

Well is drilled with 8.5 inch bit to 9,015 MD/8,505 TVD with oil based mud (9.5 ppg). Estimated hole sized based on an open hole log is 8.6 inch.

Previous casing size is 9-5/8” and its shoe is at 6,500 MD/5000’TVD.

Plan to run 7” casing and planned shoe depth at 9,000’MD/8,500’TVD.

There is one float collar at 8960’MD/8470’ TVD.

Top of cement is 2000 ft above 9-5/8” casing.

Spacer volume is from top of cement to surface.

Casing information

7” casing ID = 6.185”

9-5/8” casing ID = 8.85”

Use hole size measured from the open hole log to determine cement volume.

The well schematic should look like this.

 

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Cement Calculation Overview and Basic Terms that People Should Know

Cement slurry calculation (volume, density, yield) are quite simple and the basic behind is mass balance calculation. Cement calculation for common liquid and/or solid additive is pretty easy to understand. However, complex cement slurry as foam cement is almost not possible to do it by hand due to its complexity and for this case, you might need service company cement program to solve the problem. In this blog, I will write articles showing the cement calculation of common liquid and/or solid additive which you almost see every cement job on the rig.

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Drill Pipe Pressure Schedule Calculation for Wait and Weight Well Control Method

This example demonstrates how to determine drill pipe pressure schedule for wait and weight method.

 

Well Information

Current mud weight = 9.5 ppg

Pump output = 0.1 bbl/stroke

Well depth = 9000’MD/9000’TVD

Drill string capacity = 0.0178 bbl/ft

Surface line volume = 15 bbl.

Shut in casing pressure = 700 psi

Shut in drill pipe pressure = 500 psi

ICP = 1600 psi at 30 spm as kill rate

Please follow steps below to determine the drill pipe pressure schedule (step down chart).

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Formulas for Wait and Weight Well Control Method

There are some well control formulas that you need to know for wait and weight method.

 

1. Kill Weight Mud

KWM = OMW + [SIDPP ÷ (0.052 x TVD)]

Where;

KWM is kill weight mud in ppg.

OMW is original mud weight in ppg.

SIDPP is shut in drill pipe pressure in psi.

TVD is true vertical depth of the well in ft.

Note: Read more about it>> Kill Weight Mud

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Surface Pressure During Drill Stem Test

Drill stem test or well test is mostly conducted for exploration wells in order to see how much hydrocarbon can be produced for the reservoir, estimate reservoir boundary, determine rock properties, etc.

This topic will teach you how to estimate surface pressure during drill stem test.

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