Characterization On Sand Body And Distribution Of Remaining Oil In X₅² Formation Of Kekeya Condensate Gas Field

It has been more than 30 years since the exploration and development of Kekeya Condensate Gas Field.The development becomes more and more difficult in the middle and late stages of the oil field.In order to further stabilize the production capacity of the gas field,it is imperative for the old area to tap potential.The development has been reduced in the main production layer of the Xihefu Formation of the Kekeya Gas Field except X52 Section.Thus,this research focuses on the characterization of X52 sand body and its distribution characteristics of remaining oil.Based on the cyclic correlation method and high-resolution sequence stratigraphy,the reservoir was finely divided in the study area,single sand layer and interlayer were identified,and a three-dimensional geological model of X52 Formation was established to analyze the distribution characteristics of the remaining oil.X52 formation is a set of clastic stratum,mainly composed of fine sandstone,siltstone and mudstone interbeds suggested by the core observation.The X52 oil group is divided into 6 small layers(X52-1,X52-2,X52-3,X52-4,X52-5,X52-6).Each small layer is mainly characterized by positive rhythm.Among them,the X52-1,X52-3,and X52-5 layers are mainly mudstone interlayers,and the X52-2,X52-4,and X52-6 layers are the main sand layers.The division of single sandstone layer is based on the combination of thin layers of mudstone sandwich and the cyclic conversion interface.The X52 oil group was subdivided into 14 single layers,and the main production layer X52-2,X52-4,X52-6 is divided into 11 single sand layers.The types of interlayers in this area are classified into mudstone interlayers and physical interlayers(argillaceous siltstone interlayers).The section of the interlayer was established longitudinally,and the X52 oil group develops five compartments from the bottom to the top,which are between the X51 and X52 oil groups,within the 52 oil group,between the X52-2 and X52-3 oil groups,between the X52-4 and X52-5 oil groups,and between the X52-6 and X6 oil groups.In the later stages of development,based on the conditions of high water content,scattered distribution and complex types of remaining oil,the paper summarizes that there are four characteristics of remaining oil distribution from below perspectives:(1)In the high part of the structure,the remaining oil is high in abundance;(2)the degree of development of the interlayer affects the remaining oil and gas distribution;(3)the remaining oil is controlled by the difference between layers;(4)the remaining oil enrichment zone could be formed by the imperfect well pattern.