Primary Casing Cementing

Question 1

What is open hole completion

Answer 1

When casing is suspended and cemented above the producing zone

Question 2

What are other names for production casing

Answer 2

Long string, flow string, oil string, production string

Question 3

What is minimum compressive strength for cement before drilling out

Answer 3

500 psi

Question 4

Conservation Laws state that a minimum Waiting On Cement (WOC) must be take place. What is that time?

Answer 4

72 Hours

Question 5

What does WOC mean

Answer 5

WOC is non-productive time waiting on cement to develop strength and bond the casing in the hole

Question 6

The final casing string is referred as

Answer 6

Flow string, long string, oil string, production string

Question 7

Why would we pump cement in two, three, or four stages

Answer 7

To decrease the hydrostatic pressure of the fluid column in the annulus, help protect weak zones against high pressure, and help prevent lost circulation

Question 8

What primary technique do we use for cementing

Answer 8

single-stage primary cementing job using the two plug displacement method

Question 9

What is the Primary Purpose for Cementing Casing

Answer 9

Zonal isolation (Isolate wellbore in fresh water zones), Casing protection against corrosion, burst, collapse, and drilling shocks

Question 10

The proper performance of the hydraulic seal achieves the following

Answer 10

Excludes unwanted fluids from the production stream, confines stimulation treatments to the producing formation, assures integrity of the casing shoe for well control, exercises control over the production formation, prevents contamination of freshwater aquifers by formation fluids

Question 11

Set cement must develop sufficient mechanical strength to

Answer 11

Prevent fracture or shatter when perforated, provide casing support, absorb shock of the drill collars when drilling out, prevent casing buckling, support the formation

Question 12

What purpose does conductor casing serve

Answer 12

1. Serves as a conduit for raising circulating fluid high enough to return to the pit
2. Supports part of the wellhead load where the ground support is inadequate or where the well is going to be drilled to an extreme depth.
3. Prevents washing out under rig
4. Confines circulating fluids

Question 13

Is a BOP stack attached to the conductor casing

Answer 13

No

Question 14

What is the depth range for conductor casing

Answer 14

20 to 1,500 ft.

Question 15

What are the ranges for conductor casing size

Answer 15

16 inch to 30 inch

Question 16

What are the recommended cements for conductor casing?

Answer 16

1. Accelerated neat cement.
2. Ready-Mix Concrete
3. Thixotropic cement
4. Lost circulation additives are commenly added

Question 17

What are best cementing practices for Conductor Casing

Answer 17

1. Inner-String Method- Cementing through drill pipe with a sealing sleeve
2. Cement using displacement fluid only, no plugs are used
3. If a plug has to be used, a wood plug needs to be used. Care must be taken when pressuring up to prevent bypassing plug

Question 18

If no cement returns to service, how should one go about getting cement to service?

Answer 18

Cement through annulus using small diameter pipe. Called a top off job

Question 19

Benefits Cementing Conductor Casing Using Inter-String Method

Answer 19

• Less costly
• Does not require large diameter plug
• Reduces cement contamination
• Reduces amount of cement to drill out
• Decreases Cementing and Pump Time
• Reduces Chance of Casing Collapse