Methods and systems for sampling heavy oil reservoirs

• US 7,464,755 B2
• Filed: 12/12/2006
• Issued: 12/16/2008
• Est. Priority Date: 12/12/2006
• Status: Active Grant

• Current Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Original Assignee: Schlumberger Technology Corporation (Schlumberger NV)
• Inventors: Edwards, John
• Primary Examiner(s): Neuder; William P
• Application Number:
  US11/609,402
• Publication Number:
  US 20080135239A1
• Time in Patent Office: 735 Days
• Field of Search: 166/264, 166/369, 166/57, 166/62
• US Class Current: 166/264
• CPC Class Codes: E21B 49/084 with means for conveying samples through pipe to surface
• CPC Class Codes: E21B 49/088 combined with sampling

Abstract

Methods and systems and are described for isolating or manipulating a sample of a heavy oil composition from a hydrocarbon reservoir. One method embodiment of the invention comprises circulating a heated fluid in a first region of a reservoir where a heavy oil composition is present or believed present using a surface pump and a well completion comprising a downhole pump for a time and flow rate sufficient to produce flowable heavy oil composition, the well completion comprising a sampling tool; and sampling the flowable heavy oil composition using the sampling tool. This abstract complies with rules requiring an abstract. It should not be used to limit the scope or meaning of the claims. 37 CFR 1.72(b).

Claims

1. A method comprising:

(a) circulating a heated fluid in a first region of a reservoir where a heavy oil composition is present or believed present using a surface pump and a well completion comprising a downhole pump for a time and flow rate sufficient to produce flowable heavy oil composition, the well completion comprising a sampling tool; and

(b) sampling the flowable heavy oil composition using the sampling tool.

2. The method of claim 1 wherein the circulating comprises installing a well completion in a wellbore near the first region of the reservoir, the well completion comprising a non-insulated tubing, a downhole pump connected to an end of the non-insulated tubing, and a bypass tubing.

3. The method of claim 2 comprising inserting an insulated coiled tubing through the bypass tubing, a distal end of the insulated coiled tubing having the sampling tool affixed thereto.

4. The method of claim 3 wherein the heated fluid is a non-volatile oil, and the circulating comprises pumping the heated non-volatile oil through the insulated coiled tubing and into the first region of the reservoir using the surface pump.

5. The method of claim 4 wherein the circulating comprises pumping at least a portion of the heated non-volatile oil to the surface using a downhole pump until a heated heavy oil composition begins to flow from the first region of the reservoir.

6. The method of claim 5 comprising stopping the surface pump, thus stopping pumping of the heated non-volatile oil, while maintaining pumping using the downhole pump.

7. The method of claim 1 comprising inserting a plug in the wellbore near the first region after the sampling so that heavy oil composition near the first region may not flow.

8. The method of claim 1 comprising analyzing viscosity of the flowable heavy oil composition.

9. The method of claim 8 comprising repeating the circulating, sampling, and analyzing steps at a plurality of regions in the reservoir.

10. The method of claim 1 comprising synchronizing the sampling to occur substantially immediately after the circulating is stopped.

11. The method of claim 1 wherein the heated fluid is selected from organic fluids, inorganic fluids, and combinations thereof.

12. The method of claim 11 wherein the heated fluid is organic and is selected from non-volatile light oils or a combination of non-volatile light oils.

13. The method of claim 1 comprising measuring temperature vs. time on, at, or inside the sampling tool at the first region of the reservoir, and optionally recording the sampling temperature vs. time.

14. The method of claim 13 comprising controlling temperature of the heavy oil on, at, or inside of the sampling tool using the heated fluid.

15. The method of claim 14 comprising adjusting temperature of the heated fluid, and thus to the first region being sampled, using a surface heater.

16. The method of claim 15 comprising repeating the sampling, adjusting temperature, and temperature measuring at different regions of the reservoir and measuring amount of production of the heavy oil recovered as a function of temperature and/or depth or region of the reservoir.

17. A method for obtaining a heavy oil sample from a reservoir comprising:

(a) installing a well completion in a wellbore near a first section of a heavy oil reservoir, the well completion comprising;

(i) a non-insulated tubing;

(ii) a downhole pump connected to an end of the non-insulated tubing; and

(iii) a bypass tubing;

(b) inserting an insulated coiled tubing through the bypass tubing, a distal end of the insulated coiled tubing having a sampling tool affixed thereto;

(c) pumping a heated non-volatile oil through the insulated coiled tubing and into the first section of the reservoir using a surface pump;

(d) pumping at least a portion of the heated non-volatile oil to the surface until heated heavy oil begins to flow from the first section of reservoir;

(e) stopping the surface pump, thus stopping pumping of the heated non-volatile oil, while maintaining pumping of fluid using the downhole pump; and

(f) sampling heavy oil using the sampling tool.

18. A system comprising:

(a) a well completion in a wellbore near a first section of a heavy oil reservoir, the well completion comprising a non-insulated tubing, a downhole pump connected to an end of the non-insulated tubing, and a bypass tubing having an internal diameter;

(b) an insulated coiled tubing having an external diameter less than the internal diameter of the bypass tubing, allowing the insulated tubing to move longitudinally through the bypass tubing, a distal end of the insulated coiled tubing having a clock-operated, battery-powered sampling tool affixed thereto; and

(c) a surface pump for pumping a heated non-volatile oil through the insulated coiled tubing and into the first region of the reservoir.

19. The system of claim 18 wherein the downhole pump is selected from progressive cavity pumps and electric submersible pumps, and wherein the insulated tubing comprises a tubing in tubing design comprising an inner tubing and an outer tubing forming an annulus therebetween, the annulus filled with an insulating material.