A method for on-site judgment of T-shaped fracture formation risk and corresponding fracturing technology

Abstract

A method for on-site discrimination of T-shaped fracture formation risks and a corresponding fracturing process belong to the technical field of hydraulic fracturing in oil and gas fields. A method for on-site discrimination of T-shaped fracture formation risks, comprising the following steps: (1) the first perforation adopts a single-stage perforation method, and the perforation length is 1-3m; (2) small-scale fracturing tests and pressure drop analysis are carried out, The pressure drop test time is more than 1.5-2.0 times of the small-scale fracturing construction time; (3) Calculate the pump stop pressure gradient and fracturing fluid loss coefficient; (4) If the pump stop pressure gradient is greater than 0.023MPa / m, and the fracturing If the fluid loss coefficient is 1-2 orders of magnitude higher than the matrix fluid loss coefficient, the risk of T-shaped seam formation is high. For mines with a high risk of T-shaped fractures, it is important to improve the productivity of shale gas wells by optimizing perforation methods and fracturing parameters to improve fracture creation efficiency, form vertical fractures as much as possible, and avoid forming a large number of horizontal fractures and T-shaped fractures. significance.

Description

technical field [0001] The invention belongs to the technical field of hydraulic fracturing in oil and gas fields, and mainly relates to a method for on-site discrimination of T-shaped fracture formation risks and a corresponding fracturing process. Background technique [0002] In the past decade, hydraulic fracturing technology has become a key technology for shale oil and gas development, and experts and scholars have paid more and more attention to the research on shale oil and gas fracturing technology and fracture morphology. The connection between hydraulic fracturing fractures and weak bedding planes will form special fracture extension and distribution, which will affect the vertical expansion of fractures, and extend horizontally after encountering bedding planes, forming T-shaped fractures or inverse fractures. T-seam. The existence of T-shaped fractures reduces the effective height of hydraulic fracturing fractures. The fractures have complex shapes, large fluid...

AI Technical Summary

Problems solved by technology

The existence of T-shaped fractures reduces the effective height of hydraulic fracturing fractures. The fractures have complex shapes, large fluid loss, and narrow fracture widths. Conventional perforation methods and sanding processes have poor adaptability, which has a significant adverse effect on the productivity of horizontal wells.

At present, there is a lack of methods at home and abroad to judge whether T-shaped fractures are easy to form during on-site construction, and there is also a lack of research on corresponding fracturing techniques