Sub-layer Correlation And Reservoir Characteristics Of Fuyu Oil Layer In Haituozi Area

Haituozi, located in the western frontal zone of South Songliao Basin, is an area where a lot of discoveries of oil and gas have been made by Jilin Oilfield in recent years. But the focus of the Fuyu oil layer of Haituozi Area is not yet in depth anatomy, and the law of oil and gas accumulation is not clear so far. Using the theory and technology of high-resolution sequence stratigraphy, the paper carries out the division of high-resolution sequence stratigraphy of Fuyu oil layer in Haituozi area. Based on these researches, sub-layer correlation and sedimentary microfacies are studied and the conditions of hydrocarbon accumulation are analyzed. Doing all these is in order to provide a geological basis for further exploration and reservoir development.Through core observation, analyzing well log stacking patterns change, identifying the turnaround surface of base-level cycles, three and a half short-term base-level cycles (the 5th order sequence) are divided in Fuyu oil layer. Moreover, as short-term base-level cycle a unit, high-resolution sequence stratigraphy framework is constructed and characters of sequences are analyzed in the sequence framework.Under the control of high-resolution sequence stratigraphic framework, fine sub-layer correlation is studied, and 12 genetic stratigraphic sub-layers are divided in Fuyu oil layer by considering the relationship of sedimentary microfacies characteristics and base-level changes, identifing"the maximum flooding surface"and determing the reservoir fluid consistency.A variety of sedimentary microfacies types are identified by the research of core, electrofacies and seismic attributes. The fluvial-floodplain sediments with the main microfacies of river channel, interchannel, crevasse channel, crevasse splay and flood plains are developed in the lower part of Fuyu oil layer. The delta front, offshore-shallow lake sediments with the main microfacies of distributary channel, mouth bar, sand sheet and offshore-shallow lake mud are developed in the upper part of Fuyu oil layer. The semi-deep lake and turbidite fan sediments with the main microfacies of semi-deep lake mud, turbidite channel and turbidite sheet are developed at the top of Fuyu oil layer.Through the sand rate statistics and preparation of sedimentary microfacies distribution maps, the sedimentary microfacies distribution in each sub-layer and vertical evolution law are cleared. The river model of the lower part of Fuyu oil layer are established.Through researching the reservoir sand body, the geological conditions of oil and gas accumulation and the test oil production data in this area, the reservoir types are analyzed, and these mainly contain fault reservoir, fault-lithologic reservoir, lithologic reservoir and structural stratigraphic reservoir. The main river channels, crevasse channels and a small number of crevasse splays at the lower, the underwater distributary channel at the upper and the turbidite body at the top part of Fuyu oil layer are good oil reservoir. The reservoirs are developed under the control of the combined effects of fault, sand body distribution and structure, and three wells are proposed based on this study.