A fracturing method for deep shale gas "v" pressure curve

Abstract

The invention discloses a fracturing method for a "V"-shaped pressure curve of deep shale gas. Including: (1) evaluation of key reservoir parameters; (2) optimization of fracture parameters and fracturing construction parameters; (3) determination of perforation location and perforation operation; (4) acid pretreatment; Joint construction with low-viscosity slick water; (6) construction of low-viscosity slick water plus powdered pottery with different sand-to-liquid ratios; (7) medium-viscosity slick water plus medium-sized proppants with different sand-to-liquid ratios; (8) high-viscosity slick water The large particle size of the glue carries the proppant construction; (9) Displacing operation. The method of the present invention enhances the complexity of deep shale gas fracturing fractures, improves the filling rate of fracture systems of different scales such as near well, far well, main fractures and micro fractures, and improves the effective volume of deep shale gas stimulation, The effect of increasing production and stabilizing production after pressing has been improved.

Description

technical field [0001] The invention relates to the field of oil and gas exploitation, in particular to a fracturing method for a "V"-shaped pressure curve of deep shale gas. Background technique [0002] With the deepening of shale gas exploration and development, shale gas with a vertical depth of more than 3500 m has basically been commercially developed, but the importance of deep shale gas with a vertical depth of more than 3500 m has become increasingly prominent. Only in the Sichuan Basin, deep shale gas The amount of natural gas resources is more than one trillion cubic meters. At present, the production of deep shale is low after gas pressure, and the decline is fast, so it is difficult to obtain economic development value. From a technical point of view, the difficulties of deep shale gas fracturing are mainly as follows: [0003] 1) With the increase of burial depth, the three-dimensional stress increases. Among them, the increase of the two-dimensional horizont...

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Problems solved by technology

[0003] 1) With the increase of burial depth, the three-dimensional stress increases. Among them, the increase of the two-dimensional horizontal stress difference increases the difficulty of fracture steering and reduces the complexity of fractures; the increase of vertical stress makes horizontal bedding fractures or It is more difficult to open and extend the grain seam, which reduces the lateral spread of the main fracture;

[0004] 2) The increase of temperature and pressure enhances the plasticity of the rock. Therefore, the crack initiation and extension pressure increase, and the embedding depth of the proppant also increases, which reduces the fracture conductivity;

[0005] 3) As the effective closure stress increases, the proppant fragmentation rate increases, which further reduces the conductivity of the fracture;

[0007] In view of the above limitations, deep shale gas fracturing technology has been developed into a multi-stage variable parameter fracturing technology, including variable viscosity, variable displacement, variable proppant particle size, etc., but the lack of implementation control technology makes it difficult to operate on site. Completely follow the design, so it is difficult to achieve the designed stimulation effect, which is not conducive to improving the complexity of deep shale gas fractures and maximizing the effective stimulation volume

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