Cemented Open Hole Selective Fracing System

• US 20080302538A1
• Filed: 06/08/2007
• Published: 12/11/2008
• Est. Priority Date: 03/15/2005
• Status: Active Grant

• Current Assignee: Peak Completion Technologies Incorporated
• Original Assignee: Peak Completion Technologies Incorporated
• Inventors: Hofman, Raymond A.
• Granted Patent: US 7,926,571 B2
• Time in Patent Office: Days
• US Class Current: 166/373
• CPC Class Codes: E21B 2200/06 Sleeve valves
• CPC Class Codes: E21B 43/00 Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells applicable only to water E03B
• CPC Class Codes: E21B 43/11 Perforators; Permeators
• CPC Class Codes: E21B 43/12 Methods or apparatus for controlling the flow of the obtained fluid to or in wells E21B43/25 takes precedence; valve arrangements E21B34/00
• CPC Class Codes: E21B 43/14 Obtaining from a multiple-zone well
• CPC Class Codes: E21B 43/26 by forming crevices or fractures

Abstract

A cemented open hole selective fracing system and method are shown. In the producing zone, an open hole is drilled therein and a production tubing is cemented in place. At preselected locations along the production tubing, the production tubing will have sliding valves located there along. The sliding valves may be selectively opened, and the cement around the sliding valve dissolved. Thereafter, the formation may be fraced immediately adjacent the opened sliding valve. By selectively opening different combinations of sliding valves, fracing can occur in stages with more fracing pressure and more fracing fluid being delivered deeper into the formation. Just as the sliding valves can be selectively opened, the sliding valves can also be selectively closed to protect the production of the well.

Claims

1. A method of petroleum production from at least one open hole in at least one petroleum production zone of an oil and/or gas well comprising the steps of:

locating a plurality of selectively-openable sliding valves spaced apart along a production tubing at predetermined locations, wherein at least one of said plurality of selectively-openable sliding valves is a ball-and-seat valve;

inserting said plurality of selectively-openable sliding valves and said production tubing into said at least one open hole;

cementing said plurality of selectively-openable sliding valves and said production tubing permanently in place in said at least one open hole, said predetermined locations along said production tubing being in said petroleum production zone in said at least one open hole;

selectively opening said at least one of said plurality of said selectively-openable sliding valves without jetting or cutting tools and selectively dissolving said cement adjacent thereto to establish access therefrom to said at least one petroleum production zone;

selectively fracing through said selectively opened of said plurality of said selectively-openable sliding valve with fracing material; and

selectively producing said at least one petroleum production zone through said selectively opened of said plurality of said selectively-openable valve in said open hole of said oil and/or gas well that has been (a) selectively opened (b) selectively dissolved, and (c) selectively fraced.

2. The method of petroleum production as recited in claim 1 wherein said plurality of selectively-openable sliding valves comprises a plurality of ball-and-seat valves, each of said plurality of ball-and-seat valves having a ball seat matable to a ball that is not matable to any other of said plurality of ball-and-seat valves.

3. The method of petroleum production as recited in claim 2 wherein said locating step comprises arranging said plurality of ball-and-seat valves along said production tubing at predetermined locations such that said ball-and-seat valve having the smallest size ball seat is positioned downwell from said ball-and-seat valve having the largest size ball seat.

4. The method of petroleum production as recited in claim 3 wherein said locating step further comprises arranging all other of said ball-and-seat valves along said production tubing at predetermined locations in decreasing order of the size of said ball seats and between said ball-and-seat valve having the largest size ball seat and said ball-and-seat valve having the smallest size ball seat.

5. The method of petroleum production as recited in claim 4 wherein said selectively opening step further comprises pumping a ball matable through said production tubing to the ball seat of said selectively-openable ball-and-seat valves to be selectively opened.

6. The method of petroleum production as recited in claim 5 wherein said selectively opening step further comprises opening said ball-and-seat valves in increasing order of the size of said ball seats.

7. The method of petroleum production as recited in claim 1 including a first step of cementing a casing from a top of said oil and/or gas well downward toward said at least one open hole.

8. The method of petroleum production as recited in claim 1 including securing a well head at a top of said casing.

9. The method of petroleum production as recited in claim 8 wherein said at least one open hole is a lateral.

10. The method of petroleum production as recited in claim 8 wherein said at least one open hole consists of a plurality of lateral open holes, each of said lateral open holes having all of the steps of claim 1 performed thereof.

11. The method of petroleum production as recited in claim 10 wherein a first one of said plurality of lateral open holes may be selected by an on/off tool connecting to a first stinger on an outer end of said production tubing in said first one of said plurality of lateral open holes.

12. The method of petroleum production as recited in claim 11 wherein a second one of said plurality of lateral open holes may be selected by an on/off tool (a) disconnecting from said first stinger on said outer end of said production tubing in said first one of said lateral open holes and (b) connecting to a second stinger on an outer end of said production tubing in said second one of said plurality of lateral open holes, the steps of claim 1 being repeated.

13. The method of petroleum production as recited in claim 12 wherein the steps of claim 12 and claim 1 are repeated for each of said lateral open holes.

14. The method of petroleum production as recited in claim 8 wherein said oil and/or gas well has a plurality of petroleum production zones, said steps given in claim 1 being repeated for each of said plurality of petroleum production zones.

15. The method of petroleum production as recited in claim 1 wherein flow rate and/or fracing pressures can be maintained by opening or closing different ones of said sliding valves.

16. The method of petroleum production as recited in claim 1 wherein an undesirable production can be reduced by closing different ones of said sliding valves.

17. The method of petroleum production as recited in claim 1 wherein said selective opening step is at least one of mechanically actuated, hydraulically actuated, and electrically actuated.

18. The method of petroleum production from said at least one open hole in said at least one production zone of said oil and/or gas well as recited in claim 1 wherein said selective opening of said at least one ball-and-seat valve is hydraulically actuated.

19. The method of petroleum production from said at least one open hole in said at least one production zone of said oil and/or gas well as recited in claim 18 wherein said selective opening of other sliding valves is mechanically actuated using a shifting tool.

20. A cemented open hole selective fracing system for producing petroleum from at least one open hole in at least one petroleum production zone of an oil and/or gas well comprising:

production tubing inserted into said open hole;

a plurality of ball-and-seat valves spaced along said production tubing at predetermined locations in said at least one petroleum production zone of said oil and/or gas well, wherein each of said plurality of ball-and-seat valves has a differently-sized ball seat;

cement holding said production tubing and said plurality of selectively openable sliding valves permanently in place in said at least one open hole;

a plurality of differently-sized balls, each of said plurality of differently-sized balls being matable to only one of said differently-sized ball seats to selectively open said plurality of ball-and-seat valves;

a solvent selectively flowing through said ball-and-seat valves to dissolve cement adjacent thereto;

a fracing material selectively flowing through said ball-and-seat valves to frac into said production zone;

wherein said dissolving and fracing is repeatable as each of said plurality of ball-and-seat valves is (a) selectively opened;

(b) cement adjacent thereto selectively dissolved; and

(c) the surrounding production zone is selectively fraced.

21. The cemented open hole selective fracing system of claim 20 wherein said solvent and said fracing material are the same.

22. The cemented open hole selective fracing system of claim 20 wherein said plurality of ball-and-seat valves are located along said production tubing at said predetermined locations such that said ball-and-seat valve having the smallest ball seat is positioned downwell from said ball-and-seat valve having the largest ball seat.

23. The cemented open hole selective fracing system of claim 22 wherein all other ball-and-seat valves are arranged along said production tubing at predetermined locations in order of the size of said ball seats and between said ball-and-seat valve having the smallest ball seat and said ball-and-seat valve having the largest ball seat.

24. The cemented open hole selective fracing system of claim 23 wherein said plurality of ball-and-seat valves is openable in an order corresponding to the increasing size of said ball seats.

25. The cemented open hole selective fracing system of claim 20 wherein cement adjacent to at least one of said plurality of selectively-openable sliding valve has been dissolved with a solvent.

26. The cemented open hole selective fracing system of claim 20 further comprising a casing cemented from a top of said oil and/or gas well and extending downward toward said at least one open hole.

27. The cemented open hole selective fracing system of claim 26 further comprising a well head secured to a top of said casing.

28. The cemented open hole selective fracing system of claim 20 further wherein said at least one open hole is a lateral.

29. The cemented open hole selective fracing system of claim 28 wherein said at least one open hole consists of a plurality of lateral open holes and the system further comprises:

a plurality of production tubings, a production tubing being disposed within each of said plurality of open holes and cemented in place therein; and

at least one ball-and-seat valve located along each of said production tubings at a predetermined location and cemented permanently in place within one of said plurality of lateral open holes.

30. The cemented open hole selective fracing system of claim 29 further comprising a stinger on an outer end of each of said production tubings.