Study On The Perforation Parameters Optimization Of Volume Fracturing Wells

Volume fracturing is widely used in tight oil and shale gas development, which hasdrainage capacity, high pressure, small particle size, and small sand ratio characteristics. Dueto a sharply internal pressure rise in perforated casing in the process of high pump volumefracturing, the casing damage is frequent. The production process is often caused by thereservoir sand, resulting in the production accident. The qualitative analysis shows what isrelated to the fracturing displacement and the perforating parameter.This paper using Pro/E software to establish a three-dimensional model of the casing,imported it into finite element analysis software, then chose SOLID45unit freely meshingand imposed fixed constraints at both ends, loaded on the casing according to set conditions,maintained the two parameters of phase angle, aperture, hole density unchanged, analyzed theinfluence of the other parameters on the casing residual stress, acquired an array ofperforation parameter combinations. A three-dimensional finite element perforated casingmodel was established to analyze the strength of the security forces under the internal andexternal pressure and axial interaction, according to the fourth strength theory calculated theperforated casing’s equivalent stress, determined perforation parameter combinations underthe lower pump pressure. The analysis of strength security of the perforated casing was basedon fracture mechanics, compared the theory results to the finite element calculation, checkingstrength security of the perforated casing. The productivity analysis of different perforatedparameter combinations was on the basis of low permeability shale reservoirs productivityformula, through the study got that preferred perforation parameter with making casing safe,lower pump pressure, higher productivity.Study shows that perforation parameters have different degrees of influence on theremainder of the compressive strength of perforated casing, where the phase angle of its moresignificant impact. The perforated casing collapse does not occur during the process ofvolume fracturing by analyzing the stress distribution of the perforated casing model. Firstly,calculates the productivity ratio and internal resistance reduction of different combination ofall possible hole density, phase angle and perforated shells, then makes sure the internalresistance reduction no more than15%to choose better combinations that have preferred productivity.