Oil-water Distribution Pattern Of Yan 9 Reservoir In Changqing H Oil Area

With the increasing difficulty of main reservoir development,the exploration and development of non-main reservoir has become the top priority.The main reservoir of Yan’an Group in H oil area of Changqing oil field has water rise and oil fall,large production decline rate,high degree of recovery,and more difficult to use reserves,and the effect of technical solutions to increase production becomes low or even ineffective.In addition to the main reservoir,the Yan’an Formation reservoir in the study area also shows some prospect in the early exploration period.With the enrichment of static and dynamic data in the later stage,it is necessary to conduct systematic research on the oil-water distribution pattern in the Yan’an Formation reservoir to provide a decision basis for compensating the diminishing production of the main reservoir.This paper is guided by theories related to reservoir geology,logging interpretation and analysis,reservoir development and exploitation,combined with the regional geological profile,and makes full use of logging,drilling and recording data to carry out a systematic study of the oil-water distribution law and control factors in the study section.By dividing and comparing the substrata,the stratigraphic variation characteristics of each substratum in Yan 10-Yan 9 were analyzed,and the top surface tectonic map of each substratum was drawn and its characteristics were analyzed.By summarizing the sedimentary micro-phase types and drawing the sedimentary micro-phase map,the planar spreading characteristics of the sedimentary microphases of each sub-layer were analyzed.In addition,Petrel software was used to threedimensionally analyze each reservoir parameter,quantitatively analyze and reasonably predict the inter-well stratigraphic variation characteristics by relevant mathematical methods.Finally,the oil and water distribution pattern of Yan 10-Yan 9 in space was clarified and its controlling factors were comprehensively analyzed.The results of the study show that Yan 10-Yan 9 in the H oil area is divided into four small layers of Yan 102,Yan 101,Yan 92+3 and Yan 91,among which,the thickness of Yan 101,Yan92+3 and Yan91 and stratigraphic changes are more stable,while the thickness of Yan 102 stratigraphic changes are larger.The overall tectonic pattern is high in the east and low in the west,and two low-amplitude nose-like structures are developed.Yan 9 belongs to the curved river phase,and Yan 10 belongs to the braided river phase,and the micro-phase developed in both Yan 10 and Yan 9 are mainly river fill and flood basin.The Yan 10-Yan 9 reservoir has poor physical properties and strong non-homogeneity,and is a low-porosity and low-permeability reservoir.Among them,Yan 101 has the best oil content,with a total oil-bearing area of 6.96km2,while the other three layers are Yan 92+3(5.6 km2),Yan 91(4.55 km2)and Yan 102(2.21km2)in order.Crude oil is mainly distributed in "stripes" and "ellipses" locally in the low amplitude nose formation area located in the river,the thinnest oil layer is 2 m and the thickest oil layer is 15.7 m.The low-amplitude nose-like structure provides favorable pointing for crude oil enrichment and provides good trap conditions,which is the main factor controlling oil and water distribution;secondly,the sedimentary phase controls the distribution of reservoirs and thus affects the distribution of oil and water.