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Method for improving fracture complexity and transformation volume of deep shale gas

A technology for transforming volume and shale gas, which is applied in the direction of production fluid, earthwork drilling, wellbore/well components, etc.

Active Publication Date: 2021-01-22
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Suitable for deep shale gas reservoirs

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0076] In a deep shale reservoir, the KY-2HF well is 3,700 meters deep and can be constructed by the method provided by the present invention.

[0077] Step (1) Parameter evaluation and optimization

[0078] Including: evaluation of key shale parameters, determination of cluster perforation position, optimization of fracture parameter system and optimization of fracturing operation parameters;

[0079] Using the method of W cloth joints, the optimal half-length of cracks is 200-220m, the conductivity is 2-5dc.cm, and the optimized maximum construction displacement is 14m 3 / min, optimized high viscosity fracturing fluid 665m 3 , the amount of low-viscosity slippery water is 1015m 3 , the amount of medium viscous slippery water is 750m 3 .

[0080] Step (2) joint construction of bridge plug and cluster perforation;

[0081] The length of each perforation cluster is 1.5m, the hole density is 16 holes / m, and the hole diameter is 11mm.

[0082] Step (3) acid pretreatment ope...

Embodiment 2

[0104] A deep shale reservoir with a well depth of 3,700 meters can be constructed by the method provided by the present invention.

[0105] Step (1) Parameter evaluation and optimization

[0106] Including: evaluation of key shale parameters, determination of cluster perforation position, optimization of fracture parameter system and optimization of fracturing operation parameters;

[0107] Using the method of W cloth joints, the optimal half-length of cracks is 220-250m, the conductivity is 2-6dc.cm, and the optimized maximum construction displacement is 16m 3 / min, optimized high viscosity fracturing fluid 433m 3 , the amount of low-viscosity slippery water is 975m 3 , the amount of medium viscous slippery water is 700m 3 .

[0108] Step (2) joint construction of bridge plug and cluster perforation;

[0109] The length of each perforation cluster is 1.2m, the hole density is 13 holes / m, and the hole diameter is 9.5mm.

[0110] Step (3) acid pretreatment operation;

...

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Abstract

The invention discloses a method for improving the fracture complexity and transformation volume of deep shale gas. The method comprises the following steps of (1) parameter evaluation and optimization; (2) bridge plug and cluster perforation combined construction; (3) acid pretreatment operation; (4) fast gel breaking of high-viscosity fracturing fluid for main fracture making construction; (5) supercritical carbon dioxide injection construction; (6) construction by low-viscosity slickwater carrying an ultralow-density proppant; (7) variable-viscosity slickwater slug type sand adding construction; (8) construction of high-viscosity glue solution with a high sand-to-liquid ratio; and (9) displacement operation. The method has the advantages that on the basis of conventional reservoir evaluation, high-viscosity glue solution is used for main fracture making construction; and the characteristic of ultra-low viscosity of supercritical carbon dioxide is utilized, so that the supercriticalcarbon dioxide easily enters various small-scale fracture systems, the fracturing pressure and the extension pressure of multi-scale fractures are greatly reduced, and the fracture complexity is promoted to be greatly improved.

Description

technical field [0001] The invention relates to the technical field of petroleum exploitation, in particular to a method for increasing the complexity of fractures and the reformed volume of deep shale gas. Background technique [0002] At present, there are still many problems in volumetric fracturing of deep shale gas. In fracturing operation, the main performance is high construction pressure, low sand-to-liquid ratio, small sand addition, and even early sand plugging; after fracturing, single well production is low , rapid decline, no economic mining value. The main reasons for this result are that the fractures are single in shape, not complex enough, the main fractures have low conductivity and rapid decline, and the development of branch fractures and micro-fractures is low, let alone the conductivity. Therefore, the volume of fracture stimulation is small, and as the conductivity decreases or even fails, the above-mentioned fracture stimulation volume is further red...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B43/267G06F30/20
CPCE21B43/26E21B43/267
Inventor 蒋廷学周珺路保平卞晓冰吴峙颖苏瑗李奎为
Owner CHINA PETROLEUM & CHEM CORP