Study On Secondary Encryption Scheme Of CXCY Block In Low Permeability Reservoir

The CXCY block of Daqing Chaoyanggou Oilfield is a low-permeability fractured reservoir,which was put into operation in 1988.After more than 30 years of water flooding development,the injection-production well pattern has been adjusted from 300m×300m reverse nine-point base well pattern to one infilled well pattern,and good results have been achieved.With the extension of development time,the block has entered the stage of high water cut,water cut rising speed and production decline rate is accelerated,the low degree of sand control,the reservoir using inequality,strong heterogeneity,well spacing density is low,and blocks of enrichment of remaining oil,still has a large potential of the infilled adjustment of the whole,and is developing into the middle important measures to improve the development effect,is also the most direct and effective use of residual oil and enhance oil recovery.Aiming at the problems of poor oil reservoir utilization and low water drive recovery after primary infilling in low permeability fracture block,this paper carried out research on optimal design of secondary infilling well pattern in CXCY block.First of all,the application of Petrel geological modeling software,set up in accordance with CXCY block geological characteristics of phased fine geological model of attribute parameters such as porosity,permeability,saturation and sedimentary characteristics have good consistency,using the Eclipse software to coarsening of geological model,the equivalent simulation start-up pressure gradient,fracture parameter correction fitting block for low permeable fracture reservoir water flooding history matching,the fitting error is within 3%;And then studied CXCY block current and water drive reservoir,at the end of that a longitudinal plane sand body characteristics of remaining oil distribution,to determine the remaining oil types to plane interference,high water flooded layer rhythm at the top of the model is given priority to,more than 44% of the total remaining geological reserves,conventional oil Wells and water injection parameter adjustment is difficult to effectively use,the need for secondary encryption;Finally should be designed three kinds of encryption methods and three kinds of oil Wells Wells encryption,a total of nine secondary well pattern deployment method,numerical simulation respectively to predict the moisture content of each scheme of water flooding for 10 years,oil production rate and annual oil production and recovery degree development index changes,combined with economic evaluation,to determine the optimal solution for oil well not offset + Wells all encryption + old well the whole focus of secondary well pattern encryption scheme,forecast to improve oil recovery by 5.87%.After the secondary well pattern encryption in the CXCY block was completed,the daily fluid production in the whole area increased from 53.5t to 97.3t,the daily oil production increased from 8.3t to 23.3t,the water cut in the well area decreased from 84.5% to 76.1%,and the recovery rate increased from 0.14% to 0.54%.All these have achieved good development and economic benefits.