Study On Mechanism And Parameter Optimization Of Asynchronous Injection And Production In G693 Horizontal Well

In the late stage of low permeability oilfield development,asynchronous injection-production development is one of the important methods to improve oil recovery,which has been widely used in some oilfields and achieved good results.However,the mechanism of asynchronous injection-production technology is unclear and needs further study.Although the combined development of vertical well and horizontal well in Block G693of Daqing Oilfield has achieved high production in stage,the effect of conventional unstable water injection and periodic water injection is not obvious in the late development period,and the deployment is difficult,and the contradiction between maintaining formation pressure and controlling water cut is prominent.Therefore,an unconventional water injection method,asynchronous injection and production,is proposed to fully develop the block in order to improve oil recovery and resource development.Taking G693 block as the research object,the fault model,plane model,tectonic model,sedimentary facies model and attribute model were established by using Petrel software based on geological data of the study area and well location information of 36 Wells,and the model was coarsed on the basis of retaining the model framework and flow response.The 3d geological model was imported into the numerical simulation software,and the historical fitting of the whole area and single well was completed by combining the basic reservoir parameters and production well history.Through the fitting,the fitting error of accumulative oil in the whole area was 1.66%,the fitting error of water content was 2.15%,and the fitting rate of single well was 95.4%,meeting the fitting requirements.Then,the numerical simulation technology is used to compare the synchronous injection-production technology and asynchronous injection-production technology to predict the production effect after five years.It shows that asynchronous injection-production has the advantages of large fluctuation of pressure field,wide range of saturation field,high recovery degree and slow rise of water content.Finally,comprehensive adjustment of asynchronous injection-production measures and optimization of injection-production parameters are studied.The results show that the optimal timing of asynchronous injection-production transfer in block G693 is 30%water content.For G693 channel and main sand body type,water injection intensity is 25m~3,injection-production ratio is 1.2,injection-production cycle is 30 days for injection and 30days for recovery,and soaking cycle is 30 days.Waterflood intensity of channel-to-channel sand body type is 30m~3,injection-production ratio is 1,injection-production period is 30 days for injection and 120 days for production,and the soaking period is 30 days.By applying the optimization results of water injection parameters to the actual model horizontal block,and predicting the development index results after 20 years,the recovery degree of 22 oil Wells in this block increases from 32.60%to 34.90%,an increase of 2.3%.The application of asynchronous injection-production technology in the low permeability oil field with horizontal combination provides a new idea for further tapping remaining oil potential,which has a reference significance for improving the development effect of low permeability oil field.