Study On The Influence Of Dynamic Fracture On Formation Pressure Distribution

In the process of long-term water injection,the low permeability fractured reservoirs are closed and filled with natural fractures that are excited and resurrected.The presence of natural fractures affects the formation pressure distribution and is not conducive to adjusting the well drilling safety.In view of this problem,it is be studied the distribution of pressure distribution in the injection wells,the well pressure and the pressure distribution of the overflow pressure injection wells,taking into account the influence of the natural fractures on the seepage capacity of the single natural fractures under different mechanical conditions.It is studied stress sensitivity inflects the permeability change of no cracks ’s rock matrix and close crack rock under the condition of reservoir.After the natural fractures of the reservoir are opened,considering the influence of the slit height and the crack opening length of the natural cracks,the relationship model between the seam pressure and the slit width is established based on the calculation model of the slit width.Based on the model of flowing cubic law,the relationship between fracture permeability and formation pressure considering the seam height and crack opening length of natural fractures is obtained.Then,the fractal geometry is used to describe the distribution of natural fractures in reservoirs.Based on the equivalent stacking method of natural fractures,the relationship between the permeability of the reservoirs and the permeability of the reservoirs is obtained.The pressure distribution in the formation pressure of the low permeability fractured reservoirs is calculated and analyzed by considering the fluid-solid coupling effect.The results show that the permeability of fractures is affected by reservoir formation pressure,ground stress,natural fracture occurrence,opening and closing state and crack shape;The natural fractures near the injection wells are affected by the water injection of the injection wells.The high permeability of the open natural fractures is less than the opening pressure.The pressure transfer rate is poor,which is the average formation pressure of the wellbore wells and the formation pressure;The closure of the injection wells overflows and the natural fractures close to the wellbore wells prevent the formation fluids from flowing into the injection wells and reduce the efficiency of the formation pressure at the far side of the injection wells.The overflow pressure of the injection well does not take into account the effect of the opening and closing of the natural fracture,which leads to the low pressure of the formation to be adjusted.For the overflow of the injection wells to be drilled to adjust the formation pressure forecasting,it is necessary to consider the natural fractures to open and close the formation pressure distribution to adjust the drilling well design guidance.The study is conducive to explicate the development of low permeability fractured reservoirs,affected by oil field development and regulation of formation pressure distribution.Which provides the theoretical basis for the prediction of formation pressure of well drilling and cementing in low permeability fractured reservoir.