Study on Hydrocarbon Accumulation Models in Denglouku-Yongan Area of Songliao Basin

Basing on the understanding about the tectonic and sedimentation evolution characteristics in Denglouku-Yongan area of Songliao Basin, study on hydrocarbon accumulation model has been conducted on the basis of coring, logging and seismic data, with focus on hydrocarbon migration ways and spatial combination of source rocks, reservoirs and cap rocks. In addition, the main controlling factors on hydrocarbon accumulation have been analyzed. The study results indicated that the stratigraphy in this area are characterized by double faulted sag structure, developed during rifting stage and depression stage in work area. During rifling stage, there are two hydrocarbon accumulation modes, including primary oil and gas reservoir formation and secondary oil and gas reservoir formation. During depression stage, secondary oil and gas reservoir formation and mixed oil and gas reservoir formation pattern are dominated in this area. On the basis of spatial combination of source rocks, reservoirs and cap rocks, there are three kinds of oil and gas reservoir formation models, including upper generation and lower reserving, upper reserving and lower generation, and generation and reserving in situ. The main controlling factors for so many different kinds of oil and gas reservoir formation models in this area are mainly large scale faults extending into basement, the inherited faulted structures, reversed structures, and the particular sedimentary environments.