Formation Pressure Prediction For Infill Well In Faulted Reservoir

The pressure distribution is very complicated in faulted reservoir.With the continuous development,the original pressure system was varied.Affected by faults,there are significant differences in fluid distribution and pressure distribution in reservoir,and complex situations such as kicks and leakages are prone to occur during the infill well drilling and completion operations.For example,when drilling into high-pressure reservoirs,reservoir fluids can easily invade the mud,resulting in accidents such as kicks and blowouts,affecting drilling efficiency and drilling quality.When drilling in low-pressure reservoirs,drill fluids are prone to invade the reservoir,which can damage the formation and affect well productivity.Sometimes even kicks and leaks occur alternately.Therefore,it is necessary to research the distribution of formation pressure and pressure control measures in faulted reservoir,so as to ensure the safety and efficiency of drilling well in faulted reservoir.This paper takes Penglai Oilfield as a target oilfield.On the basis of geological description and analysis,this paper studied the distribution of fluid and pressure in the reservoir under water flooding regime through numerical simulation and physical model experiments.The influencing factors of fluid and pressure distribution in the formation are clearly defined,and the effects such as faults,permeability differentials,interval between layers,and separate flood on the pressure distribution of the infill wells are evaluated.On the basis of seepage theory and fluid mechanics,and considering the influence of faults and the relationship between infill wells and surrounding wells,a prediction method for the maximum pressure in the infill well of complex faulted reservoirs was established.The faults changes the local water flooding regime.The distances to the fault,formation heterogeneity(planar and vertical)and separate flood are the main factors affecting the pressure of the infill wells.When the IWR is changing,the influence is marked in the early days,and the influence in the later period is smaller.The distance between wells and interval spacing also has an impact on the infill well pressure.The difference between the maximum pressure predicted by this method and the numerical simulation result is less than 10%,and it can be used to determine the injection wells that need to be adjusted when drilling,which has certain guiding significance for the design of drilling well completion plans.