Volume fracturing method of deep shale gas multi-scale proppant packing

Abstract

The invention discloses a volume fracturing method of deep shale gas multi-scale proppant packing. The volume fracturing method of deep shale gas multi-scale proppant packing comprises the following steps: (1) evaluating key engineering parameters of shale gas; (2) determining a fracturing fluid system and a proppant; (3) optimizing fracture parameters and fracturing construction parameters; (4) determining the position of a fracturing section shower hole and perforating parameters; (5) carrying out acid pretreatment; (6) carrying out low viscosity quick water low-displacement fracture heightcontrolling fracturing; (7) carrying out ultra low density proppant screen-out fracturing; (8) carrying out multi-scale fracture fracturing packing; and (9) according to a hole volume of each fracturing section, carrying out over-displacing operation according to 110-120%. The volume fracturing method of deep shale gas multi-scale proppant packing, disclosed by the invention, has the advantages that the net pressure is effectively increased by combining processes of optimizing acid treatment to reduce a fracture pressure, carrying out low viscosity quick water low-displacement injection fracture height controlling, screening out in a mixed ultra low density proppant fracture and so on, and through full-process small particle size proppant injection construction, the filling degree of the deep shale gas fracture system of small and micro fracture development is enhanced. Therefore, the effective volume of the fracture is further increased, and the long-time fracture flow conductivity isfurther improved.

Description

technical field [0001] The invention relates to the technical field of shale gas reservoir reconstruction, and more particularly relates to a volume fracturing method for multi-scale proppant filling of deep shale gas. Background technique [0002] At present, the exploration and development of deep shale gas is becoming increasingly urgent. For example, in the Yongchuan and Weiyuan blocks of Sinopec, most of the wells have a vertical depth of more than 3800m, or even more than 4100m. The shale gas fracturing barrier with a vertical depth of 4100m abroad has not yet been broken through. However, the geological characteristics of foreign deep shale gas are very different from those in China, mainly in terms of gas content, brittleness index, and horizontal two-dimensional stress difference coefficient, etc., which are more conducive to realizing complex fracture networks than domestic deep shale gas. It is difficult to learn from the fracturing mode and process parameters of...

AI Technical Summary

Problems solved by technology

These engineering geological parameters lead to the small width of the main fracture formed by fracturing, the fast extension speed in the direction of the fracture length, and the difficulty in continuously increasing the net pressure of the main fracture, and finally it is difficult to open other small-scale fractures, and it is even more difficult to obtain effective proppant filling. It is unavoidable if the production decline is too fast, especially if the production decline is fast, which has seriously restricted the economical and effective development of deep shale gas.

[0004] However, most of the current deep shale gas fracturing modes and process parameters still refer to the practice of medium-shallow shale gas, such as the mixed injection of medium-high viscosity slick water and medium-high viscosity glue, and the design of proppant still adopts medium-shallow shale gas. The 70-140 mesh, 40-70 mesh and 30-50 mesh of the layer, and the proportion of 70-140 mesh proppant is only 10-15%. Sometimes it is forced to cancel the 30-50 mesh proppant because of the difficulty of adding sand

This fracturing method is currently difficult to meet the needs of deep shale gas fracturing, and there have been cases of fracturing sand plugging with 70-140 mesh proppant in the field

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