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Selective cluster-by-cluster fracturing technology for horizontal wells in shale gas reservoirs

A technology for shale gas reservoirs and horizontal wells, which is applied to wellbore/well components, production fluids, and earth-moving drilling, etc. It can solve the problems of affecting the number of fracturing stages, difficult to achieve targeted stimulation, etc., and achieve flexible perforation positions. Effect

Active Publication Date: 2020-08-21
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, for shale gas reservoirs with strong inter-stage heterogeneity, it is difficult to achieve targeted stimulation; at the same time, because the current staged technology is to perform staged fracturing in the order from point B to point A in the horizontal well section, In the case of casing deformation, we can only abandon some intervals or it is difficult to achieve the purpose of staged stimulation. As of the end of 2016, the statistical results of Weiyuan Changning shale gas horizontal wells show that the cumulative length of casing deformation is about 13700m, which affects the number of fracturing stages. reach 176 segments

Method used

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  • Selective cluster-by-cluster fracturing technology for horizontal wells in shale gas reservoirs
  • Selective cluster-by-cluster fracturing technology for horizontal wells in shale gas reservoirs
  • Selective cluster-by-cluster fracturing technology for horizontal wells in shale gas reservoirs

Examples

Experimental program
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Effect test

Embodiment 1

[0033] A selective cluster-by-cluster fracturing process for horizontal wells in shale gas reservoirs, including: dividing the horizontal well section into several clusters, performing 1 to 4 clusters of sandblasting and perforating each time through coiled tubing, and then performing main fracturing, cluster-by-cluster multiple times The fracturing of horizontal wells was completed; in the later stage of the main fracturing, sand plugs were used to seal the fracture openings and the clusters were transferred. In the first cluster, coiled tubing and casing annulus were used for main fracturing or bare casing fracturing. 4 clusters use coiled tubing to lift out of the wellhead for bare casing main fracturing, and the entire wellbore maintains a full diameter during the fracturing process.

[0034] Described method specifically comprises the steps:

[0035] (1) According to the construction requirements, ground preparation work is carried out, the coiled tubing is used to wash t...

Embodiment 2

[0049] Process flow of the present invention such as figure 1 as shown, figure 1 Among them, i=1, 2... is the number of horizontal well section stimulation; n i =1, 2... is the number of construction clusters for the i-th transformation. The process of the present invention will be further described below.

[0050] Firstly, ground preparation is carried out according to the construction requirements, the coiled tubing is used to clean the well, the highest safe pump pressure is set (the safe pump pressure is generally 10~20MPa higher than the construction pressure), and the main fracturing preparation is carried out.

[0051] If the main fracturing is single-cluster fracturing, the coiled tubing with flushing head and sandblasting perforating tool is lowered, the depth is adjusted, and the first fracturing cluster is performed at the designated position of the horizontal well through the coiled tubing combined with sandblasting and perforating tools. Perform sandblasting an...

Embodiment 3

[0056] Well YSN-1 was drilled in the Silurian Longmaxi Formation, and was completed with 139.7mm reservoir casing. The drilling depth of the well is 4210m, the vertical depth is 2539.72m, the maximum well deviation is 84.25°, the entry point is at 2510m, the exit point is at 4210m, and the horizontal section is 1700m long. Well YSN-1 encountered reservoirs with good physical properties, with an average effective porosity of 3.8%, an average TOC of 3.7%, and an average total gas content of 4.3m 3 / t, the reservoir brittleness index in the horizontal section is medium. The triaxial stress of the reservoir is characterized by strike-slip faults, the difference between the maximum and minimum horizontal principal stress is large (greater than 15 MPa), the reservoir is heterogeneous, natural fractures are less developed, and the east side of the wellbore is close to the fault. The well design applies the present invention to 72 clusters of fracturing operations.

[0057] (1) The ...

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Abstract

The invention discloses a shale gas reservoir horizontal well selective cluster-by-cluster fracturing technology. The technology comprises the steps that a horizontal well section is divided into a plurality of clusters, and 1-4 clusters of jet perforation primary fracturing and multiple times of cluster-by-cluster fracturing are conducted through a continuous oil pipe each time to complete fracturing transformation of the horizontal well; in the later stage of primary fracturing, a sand plug is used for blocking a seam to carry out cluster switching, the first construction cluster uses the continuous oil pipe and a casing annulus to conduct primary fracturing or light bushing fracturing, the second to fourth construction clusters lift the continuous oil pipe out of a pithead for light bushing primary fracturing, and full bore of a whole shaft is kept in the fracturing process. Clustering and cluster switching are achieved through oil pipe multi-cluster jet perforation and seam manualplugging in the later stage of primary fracturing, mechanical packers are not needed, and selective cluster-by-cluster fracturing can be implemented in the horizontal well in any sequence at any position; the full bore of the shaft is kept all the time in the whole construction process and after construction, so that transformation size optimizing control over the shale gas horizontal well is achieved.

Description

technical field [0001] The invention relates to a method for fracturing horizontal wells in shale gas reservoirs, in particular to a selective cluster-by-cluster fracturing process for horizontal wells in shale gas reservoirs. Background technique [0002] At present, composite bridge plug staged volume fracturing technology is commonly used in the fracturing stimulation of shale gas horizontal well reservoirs in the Sichuan Basin. Complexity, overall achieved a good transformation effect. However, for shale gas reservoirs with strong inter-stage heterogeneity, it is difficult to achieve targeted stimulation; at the same time, because the current staged technology is to perform staged fracturing in the order from point B to point A in the horizontal well section, In the case of casing deformation, we can only abandon some intervals or it is difficult to achieve the purpose of staged stimulation. As of the end of 2016, the statistical results of Weiyuan Changning shale gas h...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/26E21B43/114
CPCE21B43/114E21B43/26
Inventor 朱炬辉何封张俊成石孝志肖剑峰杨海李军龙雍和毅刘桓宋丹
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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