Fracturing method for increasing full-scale crack supporting volume of deep shale gas

Abstract

The invention discloses a fracturing method for increasing the full-scale crack supporting volume of deep shale gas. The method comprises the steps of (1) key reservoir parameter evaluation, (2) geological engineering filling point selection, (3) crack parameter and fracturing construction parameter optimization, (4) acid slick water and glue solution formula optimization, (5) perforation operation, (6) acid pretreatment operation, (7) low-viscosity acid slick water injection construction, (8) small-particle-size propping agent injection, (9) variable-viscosity slick water and variable-viscosity ground cross-linked acid injection, and (10) propping agent corresponding injection corresponding to the step (9). The method can be realized in the deep shale gas reservoir fracturing process. Cracks of various scales are opened, communication and full expansion of the cracks of various scales are accelerated, the volumes of the supporting cracks of all levels are increased, the volume decreasing rate of the supporting cracks is reduced, maximization of the multi-scale crack making volume, the supporting efficiency and the supporting volume is achieved, and therefore the drainage area is enlarged, the single well yield is increased, and the stable production period is prolonged.

Description

technical field [0001] The invention relates to the technical field of shale fracturing, and more specifically relates to a fracturing method for increasing the support volume of full-scale fractures in deep shale gas. Background technique [0002] At present, the main technology used in deep shale gas fracturing is basically the technology of medium and shallow layers. Basically, a large proportion of single-viscosity slick water system and a small proportion of single-viscosity glue system are still used; proppant still adopts a small proportion of 70-140 mesh powder ceramic proppant and a large proportion of 40-70 mesh ceramsite proppant And a small proportion of 30-50 mesh ceramsite proppant, sometimes cancel 30-50 mesh ceramsite to prevent sand plugging during construction. [0003] The single-viscosity slick water and single-viscosity glue used in the above process, no matter whether their viscosity is consistent with the viscosity of the single liquid used in the med...

AI Technical Summary

Problems solved by technology

In addition, due to unreasonable optimization of proppant particle size and ratio, proppant may interfere with each other in a single main fracture, thus reducing the conductivity of the main fracture

In addition, when the proportion of small-scale fractures is small or the proportion of small-size proppant is inappropriate, small-scale fractures will close rapidly with the decrease of bottomhole flowing pressure during the production process, resulting in a rapid decline in production after fracturing

[0004] At present, stable production after gas pressure in deep shale is not ideal. In addition to geological factors, it is an indisputable fact that the support volume of fractures of various scales is insufficient and the support volume decreases rapidly.

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