The Study On The Rules Of Remaining Oil Distribution Of K₁s In Lianmuqin Oilfield In Tuha Basin

Since the development of Lianmuqin Oilfield,the oil production has gradually increased in the first stage under the influence of edge and bottom water energy;in the second stage,the production has decreased due to the increase of water cut;in the third stage,the production has remained stable through enhanced fluid production by oil wells;in recent years,the bottom water of reservoirs has been rising,the water cut of oil wells has increased rapidly,and the oil field has entered a high water cut stage,and the oil production has declined rapidly.Under the current production measures,it is more difficult to stabilize production.It is urgent to analyze seismic,logging and production performance data,implement residual oil distribution,summarize the main factors controlling residual oil enrichment at different locations,and provide geological basis for formulating targeted residual oil potential tapping schemes.Through comparing and dividing the small layers,it is determined that the I sand composition is 1 and 2 small layers,and the transverse distribution is stable.Based on the interpretation of seismic data,it is determined that the structure is anticline,and the North-South faults are developed in the center.Based on core,grain size and log data,single well facies and connected well facies analysis are carried out,and the plane distribution of sedimentary microfacies is determined by combining source direction and sand body distribution characteristics.The braided river delta front sedimentary subfacies are developed in the study area,and the microfacies are subdivided into underwater distributary channel and underwater distributary channel lateral margin.Based on the related data of lithology,physical property,electrical property and oil-bearing property,the four properties of reservoir are studied,and the relevant parameters of effective reservoir of K₁s formation are determined as follows:siltstone is the lowest requirement of lithology;oil-bearing property needs to reach oil trace level;electrical property standard is acoustic time difference greater than 276us/m,deep lateral resistivity greater than 12 ohm·m;porosity in physical characteristics needs to be greater than 19.0%,permeability needs to be greater than 20x10^-3um²,shale content should be less than 8.0%.Based on the pore-permeability interpretation model,the horizontal distribution of pore-permeability is analyzed,and the coefficient of variation,the coefficient of penetration and the range of infiltration are calculated to be 0.79,2.72 and 47,respectively,to determine the strong horizontal heterogeneity of the reservoir,and the horizontal distribution of the thickness of the barrier is analyzed to determine the interlayer heterogeneity of the reservoir.According to the dynamic data of oilfield development,the oil-water interface,water flooding degree of single well and remaining oil saturation are analyzed,and the enrichment area of remaining oil is determined.Combining with geological factors,the distribution law of remaining oil is determined:under the combined action of anticline structure and positive sedimentary rhythm,the lower part of I sand group has been completely flooded during water flooding,and the remaining oil enrichment degree of the top small layer of sand group is higher than that of the bottom two small layers;the main controlling geological factors of the high remaining oil enrichment area are determined in plane,Lian 204 well area is the main fault-controlled type and Lian 201 well is the main fault-controlled type.Area is the main control type of sedimentary microfacies,well Lian 212 is the main control type of reservoir interlayer heterogeneity,and well Lian 214 is the main control type of reservoir plane heterogeneity.