Horizontal well layer blast crack body modeling method

Abstract

The invention discloses a horizontal well layer blast crack body modeling method based on unit elimination technology in a finite element analysis method; a plane stress-displacement relation equation and a maximum tension stress brittleness fracture quasi side equation in a linear elastic fracture mechanics theory are applied so as to build up a simulation horizontal well layer blast crack body mathematical model; the modeling method comprises the following steps: horizontal well shaft instantaneous blast load characteristic rule description; model application scope selection; initial crustal stress balance; far field boundary condition setting; unit type and size selection and determination; stress wave propagation damping influence in rocks. The mathematic model can use a blast impact module of an existing finite element calculating tool to solve, and solved value simulation result can vividly and directly reflect geometry form and geometry dimension of a crack body generated by horizontal well layer blast, thus providing objective theory basis for analyzing layer blast pressing crack effect influences by different parameters.

Description

technical field [0001] The invention relates to unconventional oil and gas reservoir transformation technologies such as shale gas and tight sandstone gas in the field of oil and gas field development, in particular to a method for modeling explosion fractures in horizontal well layers for researching and analyzing reservoir crack initiation networks. Background technique [0002] For a long time, in the development of unconventional oil and gas reservoirs such as shale gas and tight sandstone gas, the staged fracturing technology of open-hole horizontal wells without strings is mostly used to create formation fracture networks to increase the oil and gas production capacity of the reservoirs. This hydraulic fracturing technology has disadvantages such as uneven fracture network and limited stimulation capacity of a single well. Therefore, relevant technicians have proposed an intralayer explosion technology, in which liquid explosives are squeezed into hydraulic fractures o...

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Problems solved by technology

Most of the domestic and foreign research on intralayer explosion technology focuses on liquid explosive formulations and performance evaluation tests, ignition and transmission methods, small-scale intralayer explosion experimental devices, and the development of rock cracking simulation devices. There is a lack of cracks formed by intralayer explosions. Therefore, it is impossible to systematically grasp the law of fracture bodies formed by explosions in horizontal wellbore layers, and it is also impossible to guide and plan the construction design of explosive fracturing in layers.

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