The Study Of Seismic Inversion Of Reservoir And Traps Evaluation In Hulihai Suken Of Qianjiadian Sag, Kailu Basin

Qianjiadian sag which consists of Baolongshan low, Hulihai low, Xiboyingzi low and Yamenyingzi low, is a secondary tectonic element of Kailu basin. And the target formation, cretaceous strata in Hulihai, is the most potential one.Based on the accurate geological model which was build up by seismic interpretation, technologies such as curves recomposition, well constrained inversion,seismic attribute analysis and NN were used in order to predict the vertical and areal distribution of sandstones. Then the article concluded the further understands about work area as follow.Based on the mud log and wire line log data, 3 main indicator strata such as shale and carbonaceous shale in Shahai formation and thick tufficeous strata in lower Jiufotang formation were identified in order to complete correlation, tie and horizon tracking.There is a complex fracture system here thus technology of cohere and dip scanning was used for ensuring existence of faults in different period and different size. About 48 faults were found in such way. And these faults always lay in the directions of NE, NNE, NW and EW. 20 structural traps were identified in eastern mild slope where faults developed dominantly.Seismic inversion was utilized in project to predict the distribution of sandstones in upper Jiufotang formation, especially the oil bearing sandstones found in QC1, Q30 and Q33.Sandstones that had similar impedance character with oil bearing sandstones were interpreted, then 9 prospective sandstones were optimized. According to the isopach and structural map of those 9 sandstones, 3 lithologic traps were identified in central low and slope.According to the percentage of sand in formation which can reveal the sedimentary character, article reviewed the sedimentary facies of work area under sedimentary background of the sag. It is concluded that sedimentary facies here mainly consists of braided river delta and lake facies. The braided river delta went into low from eastern slope in type of‘finger’or‘fan’. Being the main reservoir, sandstones derived from delta front lay around the abyss. Besides, turbidite fan was found in QC1 which located in the southwestern part of work area.