Study on Point Bar Residual Oil Distribution based on Dense Well Pattern in Sazhong Area

Abstract

Based on the dense well pattern data of PI2a unit of Putaohua oil layer in Sazhong development area of Daqing oilfield as well as modern sediment and outcrop, the paper attempts to determine point bar configuration parameters through a combination of quantitative methods to establish a three-dimensional point bar configuration model. On the basis of this model, the paper proposed a parameter-constrained three-dimensional configuration model of lateral accretion interbeds via spatial translation according to the planar trajectory of interbeds, so as to maximally restore the geological structure and ascertain the anisotropism and residual oil inside point bars. The results show that there are 15 interbeds in the study area with an azimuth of 320° and an obliquity range of 3.5°-13.1°. The interbeds average an interval of 9.5m, and each of them stretches 25m on average. The profile of interbeds is concave, which is slow, steep, slow from the bottom to the top, and the surface takes the shape of crescent. The profile of lateral accretion bodies is characterized by a echelon-like superimposed structure. The interior of point bars shows strong anisotropism due to interbeds, with residual oil being scarce at the bottom, abundant in the middle and extremely abundant at the top. Given the distribution pattern, the paper put forward suggestions for future residual oil potential tapping.