The In-situ Stress Evaluation In Low Permeability Reservoir And Its Effects On Hydraulic Fracturing

In-situ stress is the basic data of petroleum engineering and production program. Theresearch of in-situ stress in researching region, and the changing of reservoir in-situ stressplay a very important guiding role for deeply understanding low permeability reservoirmechanical characteristics, complex reservoir percolation mechanism and the dynamic ofreservoir development and so on.In the thesis, based on the low permeability reservoir geology, well logging interpretation,stress monitoring of Shengli, the methods of the field data processing and finite element areused to analyze comprehensively the part of single well in block and the field distributioncharacteristics to grasp the size of the block in-situ stress, the rule of the direction variation,which can provide the foundation for fracture, well network deployment, injection and systemoptimization development and programs adjustment.In this paper, the following researches are done:First of all, based on the optimization inversion method of the multi-well point, the stressfield numerical simulation study is carried out, and a study block of in-situ stressnumericalsimulation of the geological model is established, fracturing situ stress numerical analysis androck mechanics parameters measured are done, using the measuredsitu stress direction andvalues as constraints to carry out the numerical simulation of the block of in-situ stressfieldinversion study in order to gain the rule of the distribution of stress field, which provides thebasis for the deployment and adjustment of the lower part of the well network.Secondly, the analysis of the low penetration of the sensitive reservoir stress sensitivityare carried out based on core experiments and established core porosity-permeabilityevaluation equation.Thirdly, the reservoir stress sensitivity, non-Darcy flow and other factors are consideredbased on medium deformation-seepage coupling theory to build the overall low permeabilityreservoir fracturing well group stress field analysis model and develop corresponding finiteelement numerical simulation.At last, the impact of the pressure changes is calculated in capacity to determine the favorable opportunity of water injection. At the same time, the study has shown that thedifferences in the capacity have influence through reducing elastic energy production andwater injection maintaining reservoir energy production.