| The Chang 6 reservoir in the An 201 area of the Hujianshan oilfield is located in the middle of the northern Shanbei slope in the Ordos Basin.It began expanding production gradually in 2009.The main production layer is chang 61,which the average thickness is 16.9 m,the average porosity is 13.4%,the average permeability is 0.79×10-3um2,the producible geological resources is 1225.96×104 t.Original well adopts a 480×150m reverse rhombus nine-spot well pattern,facing the problem that corner well is flooded easily but lateral well is no effectively producted.From 2015 to 2016,the encryption adjustment experiments has been performed in three difference well patterns.At present,single well production capacity is 1.18 t/d,comprehensive water content is 40.7%,speed of geologic production is 0.53%and production degree of geological reserves is 4.38%.The oil layer of the reservoir is thick,however,facing many problems such as well developed bedding structured and natural fracture,serious contradiction between corner well and lateral well,degree of water drive is only 56.3%and infilled adjustment floping down heavily.Based on core observation,it is therefore necessary to analyze the influence of reservoir characteristics on reservoir development,sum up the law of reservoir development,evaluate the rationality of technical policies for reservoir development and formulate the next step of rational development of technology policies to resolve contradictions in the development process.The main achievements of this paper are as follows:1.The chang61 layer of the study area are divided into 8 single sand bodies,namely,chang 611-1,chang 61-2,chang 611-3,chang 611-4,chang 612-1,chang 612-2,chang 612-3 and chang 612-4.The main prodection layer is chang611-4,chang612-1.2.The study area belongs to the subfacies of the delta plain,mainly including distributary channels,distributary bay.The natural dike,breach fan and swamp microfacies are not developed.The width of the single-stage channel which the direction of material source has good connectivity is within 100 meters.3.The natural fractures,seam fracturing azimuth and the main stress on the production reservoir is all in the direction of NE72°,accounting for the water flooding among wells in the study area.4.The lateral displacement effect of primary well net is worked as expected,and the leading edge of water drive is only 40m;According to the development rules and predictions of different well networks,the first method of encrypted well network is the optimal well network adj ustment.5.The reasonable water injection intensity of basic well network,encryption method 1,encryption method 2 and encryption method 3 is about 2.61,3.53,2.97,2.43m3/d.m,and the reasonable water injection pressure is about 2.59?2.92,2.49?2.82,2.49?2.82,2.69?3.02MPa.The reasonable extraction rate is about 0.82,2.94,2.35 and 4.48%respectively. |
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