APPARATUS AND METHODS FOR WELL CEMENTING

• US 20120031614A1
• Filed: 08/04/2010
• Published: 02/09/2012
• Est. Priority Date: 08/04/2010
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (SLB)
• Original Assignee: Schlumberger Technology Corporation (SLB)
• Inventors: Rondeau, Joel, Salvaire, Andre
• Granted Patent: US 8,789,582 B2
• Time in Patent Office: Days
• US Class Current: 166/293
• CPC Class Codes: E21B 21/10 Valve arrangements in drilling-fluid circulation systems
• CPC Class Codes: E21B 33/16 using plugs for isolating cement charge; Plugs therefor stage cementing E21B33/146; spacer compositions C09K8/424

Abstract

An apparatus for regulating fluid-flow during a primary cementing job comprises a bottom cementing plug, adapted to house a one-way valve and means to regulate fluid flow through the plug interior. The apparatus is useful for minimizing or preventing free fall or U-tubing during primary cementing. The apparatus is compatible with conventional cementing-plug launching systems.

Claims

1. An apparatus for regulating fluid flow during primary cementing of a subterranean well, the well having a borehole and at least one casing string, comprising:

i. a cementing plug fitted with at least one membrane,

ii. a one-way valve preinstalled inside the plug interior; and

iii. means to regulate the fluid-flow rate through the plug interior.

2. The apparatus of claim 1, further comprising a releasable device inside the plug interior.

3. The apparatus of claim 1, wherein the one-way valve prevents fluid flow into the casing interior from the annular region between the casing exterior and the borehole wall, or the annular region between the casing exterior and another casing string.

4. The apparatus of claim 1, wherein the one-way valve is adjustable, thereby allowing regulation of the fluid-flow rate.

5. The apparatus of claim 1, further comprising one or more independent devices for controlling the fluid-flow rate, the devices comprising one or more members of the list comprising nozzles, orifices and valves.

6. The apparatus of claim 1, wherein the fluid-flow-rate is adjustable before the apparatus is inserted into the well.

7. The apparatus of claim 1, wherein the fluid-flow rate is adjustable after the apparatus is inserted into the well.

8. A method for regulating fluid flow during primary cementing of a subterranean well, the well having a borehole and at least one casing string, comprising:

(i) circulating a process fluid through the casing interior and into an annular region outside the casing;

(ii) launching into the casing interior an apparatus for regulating fluid flow, the apparatus comprising;

(a) a cementing plug fitted with at least one membrane;

(b) a one-way valve preinstalled inside the plug interior; and

(c) means to regulate fluid flow through the plug interior;

(iii) continuing to pump process fluid until the apparatus reaches and becomes lodged at the end of the casing string; and

(iv) continuing to pump process fluid until the plug membrane ruptures, thereby allowing process fluid to enter the plug interior.

9. The method of claim 8, wherein the apparatus further comprises a releasable device inside the plug interior, said device being ejected from the apparatus when process fluid enters the plug interior.

10. The method of claim 8, wherein the one-way valve is adjusted to limit the fluid-flow rate from the casing interior, through the plug interior, and into the annular region between the casing exterior and the borehole wall.

11. The method of claim 8, wherein one or more independent devices in the apparatus are adjusted to limit the fluid-flow rate from the casing interior, through the plug interior, and into the annular region between the casing exterior and the borehole wall, the independent devices comprising one or more members of the list comprising nozzles, orifices and valves.

12. The method of claim 8, wherein the flow-rate adjustment is performed before the apparatus is inserted into the well.

13. The method of claim 8, wherein the flow-rate adjustment is performed after the apparatus is inserted into the well.

14. A method for cementing a subterranean well, the well having a borehole and at least one casing string, comprising:

(i) circulating drilling fluid through the casing interior and into an annular region outside;

(ii) launching into the casing interior an apparatus for regulating fluid flow, the apparatus comprising;

(a) a cementing plug fitted with at least one membrane;

(b) a one-way valve preinstalled inside the plug interior; and

(c) means to regulate fluid flow through the plug interior;

(iii) continuing to pump drilling fluid until the apparatus reaches and becomes lodged at the end of the casing string;

(iv) continuing to pump drilling fluid until the plug membrane ruptures, thereby allowing drilling fluid to enter the plug interior; and

(v) pumping a desired volume of cement slurry into the casing interior, through the apparatus, and into an annular region outside the casing.

15. The method of claim 14, wherein the apparatus further comprises a releasable device inside the plug interior.

16. The method of claim 15, wherein the releasable device is ejected from the apparatus when process fluid enters the plug interior.

17. The method of claim 14, wherein the one-way valve is adjusted to limit the fluid-flow rate from the casing interior, through the plug interior, and into the annular region between the casing exterior and the borehole wall.

18. The method of claim 14, wherein one or more independent devices in the apparatus are adjusted to limit the fluid-flow rate from the casing interior, through the plug interior, and into the annular region between the casing exterior and the borehole wall, the independent devices comprising one or more members of the list comprising nozzles, orifices and valves.

19. The method of claim 14, wherein the flow-rate adjustment is performed before the apparatus is inserted into the well.

20. The method of claim 14, wherein the flow-rate adjustment is performed after the apparatus is inserted into the well.