The Sedimentary Characteristics Of The Xujiahe Formation And The Prediction Of Favorable Reservoir Facies Belts In The Guanyin Formation In Southern Anhui Province

Guan Yin Chang structure geographically is located around Guan Yin town, Yibin city of southwest Sichuan. Regionally it is in the southwest part of Zi Liu Jing depression along the gentle slope in southwest Sichuan basin. To the south is Da Ta Chang structure, to the west is Ma Liu Chang structure, to the east is Kong Tan structure with anticlines located between. The target formation of well Yin 36# is Xu Jia He formation, full hole coring has been carried out in Xu Jia He formation,38 cores have been cut, total footage 523.02m, core length 498.29m and the recovery rate 95.27%, which laid solid foundation for core facies study. Xu Jia He formation is divided into Xul, Xu2, Xu3, Xu4, Xu5, Xu6 from the bottom up,and Xu6 is divided into Xu61,Xu62 and Xu63 Subsegment.The shales contain thin sandstones or coal are widely distributed throughout Xul, Xu3, Xu5 and Xu62.The sandstones contain thin shales are widely distributed throughout Xu2, Xu4, Xu61 and Xu63. Xu Jia He formation is distributed stable in horizontal.By studying coring data and wireline logging data, combined with drilling, mud logging and regional tectonic data, it found that Xu Jia He formation in Guan Yin Chang structure is deposited in delta-lacustrine sedimentary facies with delta front facies, prodelta facies, shallow lake and shore lacustrine subfacies developed. Generally Xu2, Xu4,Xu61 and Xu63 are deposited in subfacies of delta front. Underwater diversion channel and channel mouth bar are favorable sedimentary microfacies. The reservoirs are generally low porosity and permeability,are mainly porous reservoirs.The reservoir space is mainly secondary interstices and microfractures. Many sets of sandstones are Stacked in vertically,and widely distributed in horizontal.All these provide basic geologic data for the oil and gas exploration of Xu Jia He formation in Guan Yin Chang area.