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Shale gas horizontal well segmented repeated fracturing method

A technology for repeated fracturing and horizontal wells, applied in the field of oil drilling, can solve the problems of insignificant improvement of the complexity of far-well fractures, poor flow follow-up of temporary plugging balls, and narrow fracture width, etc., to improve the construction effect and method. Clarity and the effect of increasing the volume of the transformation

Active Publication Date: 2021-02-02
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, because the density of the temporary plugging ball is much higher than that of the carrier fluid, and the A target point of the horizontal wellbore is generally higher than the B target point, the flow followability of the temporary plugging ball is poor. The current flow simulation results of the temporary plugging ball also prove that absolutely Most of the temporary blocking balls (generally around 80%) have blocked the cracks near the B target
At the same time, due to the large fluid loss, the fracture width of refracturing is relatively narrow, and the temporary plugging agent is easy to plug in the fractures near the wellbore during the flow process, which has little significance in improving the complexity of fractures far away from the wellbore

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] Well A has a vertical depth of 2146m, a horizontal section length of 1560m, and 15 stages of initial fracturing. By the method provided by the present invention, the steps are as follows:

[0067] (1) Perform repeated fracturing and segmentation for the horizontal wellbore that has undergone initial fracturing. The five stages of the initial fracturing stage are divided into three stages as a large stage of refracturing. From target point B to target point A are the first, second and third stages of repeated fracturing. Taking the construction of the first large section as an example, the construction process is explained.

[0068] (2) Prepare liquid temporary plugging agent to block the second and third sections. Polymers with low-harm characteristics are preferred. After formula adjustment, each liquid system has different delayed crosslinking time and gel breaking time. The viscosity of liquid temporary plugging agent in each section is required to be 200mPa.s. ...

Embodiment 2

[0083] Well B has a vertical depth of 2238m, a horizontal section length of 1850m, and 20 stages of initial fracturing. By the method provided by the present invention, the steps are as follows:

[0084] (1) Perform repeated fracturing and segmentation for the horizontal wellbore that has undergone initial fracturing. The five stages of the initial fracturing stage are divided into four stages as a large stage of refracturing. From target point B to target point A are the first, second, third and fourth stages of repeated fracturing. Taking the construction of the first large section as an example, the construction process is explained.

[0085] (2) Prepare liquid temporary plugging agent to block the second, third and fourth sections. Polymers with low-harm characteristics are preferred. After formula adjustment, each liquid system has different delayed crosslinking time and gel breaking time. The viscosity of liquid temporary plugging agent in each section is required to...

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Abstract

The invention discloses a shale gas horizontal well segmented repeated fracturing method. The shale gas horizontal well segmented repeated fracturing method comprises the following steps that (1) repeated fracturing segmentation is conducted on a horizontal wellbore subjected to primary fracturing; (2) a liquid temporary plugging agent is prepared; (3) medium-viscosity slickwater is injected for construction; (4) the liquid temporary plugging agent is injected for construction; (5) the liquid temporary plugging agent is displaced for construction; (6) a pump is stopped for 1-2 minutes; (7) fracturing construction is conducted; (8) the step (7) is repeated for 1-2 times; and (9) other large repeated fracturing segments are constructed. According to the shale gas horizontal well segmented repeated fracturing method, repeated fracturing construction can be effectively guided, the transformation size is greatly increased, the construction effect is obviously improved, and therefore the maximum economic benefits are obtained.

Description

technical field [0001] The invention relates to the technical field of petroleum drilling, and more particularly relates to a method for staged repeated fracturing of a shale gas horizontal well. Background technique [0002] It has been five years since the domestic shale gas horizontal well staged fracturing achieved a commercial breakthrough in 2012. Many wells experienced a rapid drop in wellhead pressure after fracturing, and some wells have approached the inlet pressure of surface gathering and transportation stations. Production fell rapidly. Therefore, staged refracturing of shale gas horizontal wells has been urgently put on the work schedule. Compared with the first fracturing, the staged refracturing of shale gas horizontal wells mainly has the following problems: 1) There is a lack of effective staged methods. Due to the large number of perforated holes left in the wellbore after the first fracturing, the conventional bridge plug and hydraulic injection methods...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B33/13
CPCE21B43/26E21B33/13
Inventor 蒋廷学肖博李双明王海涛卞晓冰卫然苏瑗左罗仲冠宇
Owner CHINA PETROLEUM & CHEM CORP