Hydrocarbon Accumulation Laws Research In Wutonggou Formation Of Dongdaohaizi Depression

Junggar basin is located in the north of xinjiang uygur autonomous region,which is one of the petroliferous basins with large-scale folds in the western of China.Dongdaohaizi sag is located in the central depression,which has multiple sets of reservoir-cap combination,at present,the Permian Wutonggou formation shows a good exploration prospect.The purpose of this research is to understand the geological conditions and optimize favorable target of Dongdaohaizi sag Permian Wutonggou formation,which can reduce exploration and development risk.This paper focuses on the tectonic background of Dongdaohaizi sag,although its oil and gas exploration is rather complex.Conducting Seismic interpretation with 3D seismic data.to study on Permian seismic geologic formation statistics.Then summed up the main structure of two concave and one convex.By guidance of the frame analysis and the petroleum accumulation theory research,combined with the previous studies on the characteristics of hydrocarbon source rocks,drilling,and testing in the study area and adjacent areas,based on the analysis of tectonic pattern and hydrocarbon accumulation law of Permian Wutonggou in the study area,to interpretate and describe for the structures and lithology of studied area clearly.analyse and summarise the formation characteristics of the study area in many ways,including structure characters,fracture feature,reservoir physical properties.Through log interpretation technology,can conduct the identification of oil and water layers then to guide the reservoir analysis and research.Finally,Analysis and research on the reservoir forming conditions,the hydrocarbon accumulation process,the reservoir controlling factors and the distribution rules of oil reservoir.In addition,predict and explore the oil and gas migration and accumulation of wutonggou formation,Summarizes the hydrocarbon accumulation model.predict geologic characteristic of the formation lithology reservoir and distribution enriching methods,in order to point out the step prospecting direction and advantageous area.The study shows that:(1)fracture lateral sealing effect of hydrocarbon migration makes integrated oil and gas rich by the more concentrated block reservoirs.When Yanshan II screen,the NS-trending fault of Dongdaohaizi sag control the oil and gas distribution of Permian Wutonggou formation.Oil and gas mainly distributed in the high place of the structure of DiNan 1 well west fracture.The DiNan 1 well west fracture and nearly east-west fracture constitute the master oil control framework of Dongdaohaizi sag.At present the well control level is low,cannot accurately depict the control effects of fracture,but the fracture of the lateral sealing block accumulation factors have been confirmed.(2)According to the combination of fracture and sand body,the fault runs through the sand body and communicates with oil source,then it becomes easy to hide.It has been proved Dongdaohaizi sag exist two nearly east-west fracture,DiNan8 well north fracture and DiNan1 well south fracture.Fracture communication oil source,provide an effective channel,the well which near the fracture test result is better.In contrast,no fracture communication,the hydrocarbon accumulation is difficult to access.According to describe the combination of fault and sand body,We conclude that sand body with fracture oil is easy to communication.(3)Tectonic gentle slope belt is easy to form favorable top sealing conditions and lateral sealing conditions,oil and gas relatively easy accumulation,tectonic gentle slope belt and the sand body formation and distribution are closely related,of which the position of the nose is most favorable.The relationship between hydrocarbon accumulation and Fault,deposition,slope breaks,the feature of lithologic traps are studied further,with the study of lithologic reservoir of Dongdaohaizi sag in Permian as the focus.Through research the reservoir accumulation conditions,the lithologic reservoir mode of Permian Wutonggou formation is set up,it can better guiding the next exploration target selection,reduce exploration and development risk.