Method to prevent gas channeling after liner cementing of high pressure gas well

A liner cementing and high-pressure gas technology, applied in wellbore/well components, earth-moving drilling, flushing wellbore, etc., can solve the problem of not being able to feed into the pipe string and connecting to the check valve, etc.

Active Publication Date: 2021-07-06
CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, after the cement slurry injection is in place and the pump is stopped, the feeding drilling tool needs to be lifted away from the cement plug surface. The outer diameter of the sand control cap at the front end of the feeding tool is relatively large. It has not been possible to find a practical solution to complete the tripping cycle operation without inducing gas channeling.
The sending pipe string of the cementing liner is different from the drilling string. In order to ensure the diameter of the rubber plug, a check valve cannot be connected to the sending pipe string, so the pressure controlled tripping method of the drilling process is not suitable for the liner cementing Drilling operation after bumping

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  • Method to prevent gas channeling after liner cementing of high pressure gas well
  • Method to prevent gas channeling after liner cementing of high pressure gas well

Examples

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Effect test

Embodiment 1

[0040] A method for preventing gas channeling after liner cementing of a high-pressure gas well, which mainly includes: in the mud replacement stage of liner cementing, replacing heavy drilling fluid in the middle of the drilling tool to establish casing pressure in the next tripping stage; After the slurry replacement operation is completed, with the help of the casing pressure established by the heavy drilling fluid sent into the drilling tool, the surface back pressure pump and the throttle valve group work together to maintain the liquid level of the drilling tool water eye and achieve constant casing pressure tripping; Drill to the designed well depth, implement different ground return times for different annulus slurry columns at different stages of heavy drilling fluid in the drill tool, heavy drilling fluid exiting the pipe shoe, all the heavy drilling fluid reaching the annulus, and the heavy drilling fluid circulating out of the wellhead. Pressure compensation, so tha...

Embodiment 2

[0042] A method for preventing gas channeling after liner cementing of a high-pressure gas well, specifically comprising the following steps:

[0043] a. Test liner cementing operation pressure equivalent density ECD max ;

[0044] b. Circulating to reduce the drilling fluid density, and testing the equivalent gas density ECD of the liner cementing operation min ;

[0045] c. Control the pressure equivalent of the leakage layer at ECD min ~ECD max Inject cement slurry within the safety window;

[0046] d. After the replacement slurry is in place, it is sent into the drilling tool to the safety interface and circulated for waiting;

[0047] e. Turn on the pump to circulate the well.

[0048] In the step a, after the drilling is completed, the drilling tool is lowered to the bottom of the well, and after the aftereffect is removed by circulation, a pressure test is carried out.

[0049] The specific method of step a is: gradually increase the displacement, and through the a...

Embodiment 3

[0064] Attached below figure 1 and figure 2 The present invention is described in detail:

[0065] A high-pressure gas well in the western Sichuan area was subjected to 177.8mm liner suspension cementing operation, and the designed amount of cement slurry was injected for slurry replacement. Send into the drilling tool well section 0 ~ 3725.79m, the replaced mud contains 2.03g / cm 3 Original drilling fluid and 2.36g / cm 3 Weighted drilling fluid, where the weighted drilling fluid is sent into the drilling tool for a well section of 1800-2900m. After the slurry replacement is in place, turn off the rotary control head to pull out the drill, and the initial casing pressure is 4.9Mpa. During tripping, the back pressure pump continues to supplement the pressure in the annular space, the throttle valve group responds dynamically, and the liquid level in the hole of the drilling tool is unknown, and the casing pressure is always controlled at 4.9±0.1Mpa to achieve a constant casi...

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Abstract

The invention discloses a method for preventing gas channeling after liner cementing of a high-pressure gas well. Casing pressure: After the slurry replacement operation is completed, with the help of the casing pressure established by the heavy drilling fluid sent into the drilling tool, the surface back pressure pump and the throttle valve group work together to maintain the liquid level of the drilling tool water eye and achieve a constant casing pressure. Drilling; tripping out to the design well depth, implement different annulus slurry column time at different stages of heavy drilling fluid in the drill tool, heavy drilling fluid exiting the pipe shoe, all the heavy drilling fluid reaching the annulus, and the heavy drilling fluid circulating out of the wellhead. Ground back pressure compensation, so that the high-pressure air layer is stable without pressure leakage. The invention aims at the fine pressure control of the annulus after the completion of the cementing injection of the cement slurry, realizes the full pressure control of the liner cementing without short boards, and eliminates the loss of weight caused by the drilling suction and gelation during the stationary period of the annulus cement slurry column after the cementing gas channeling phenomenon.

Description

technical field [0001] The invention relates to a method for preventing gas channeling after cementing of a liner pipe of a high-pressure gas well, which is used for the cementing liner operation of oil and gas exploration and development, and belongs to the technical field of oil and gas field cementing engineering. Background technique [0002] The Sichuan-Chongqing area is a basin area with complex geological structures, large horizontal differences in strata, many vertical oil and gas water leakage shows, and many pressure layers, especially in the Lower Permian and below deep reservoirs in the western Sichuan exploration area, where the vertically complex pressure layers It makes it difficult for the casing of each layer to effectively isolate different formation pressures in sections, resulting in the coexistence of multiple complex engineering conditions such as blowout, leakage, sticking, collapse, and high-pressure brine in the same well section. Drilling encounters...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B33/13E21B21/00
CPCE21B21/00E21B33/13
Inventor 鲜明余才焌冯予淇吴朗聂世均刘洋曾凡坤刘世彬杨向宇赵启阳
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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