Geological Characteristics And Favourable Target Prediction Of Es₂¹⁰ Formation In Shishen 100 Area

The main development layers of the Shinan oil field are in the middle of the third member of Shahejie formation. In the course of drilling, varying degrees of indication of oil and gas were found in the tenth sand group in the second member of Shahejie formation. In the process of comprehensive regulation of old oil region, several wells found oil layers in the tenth sand group in the second member of Shahejie formation, indicating the impotence of this layer on rolling exploration and development. However, this layer is not the main development layer, so there are still many problems in the study of sedimentary laws and reservoir characteristics, which restraint the rolling exploration of the tenth sand group. Therefore, this paper studied the geologic characteristics of the study area, and proposed proposition for the next step of rolling exploration.In view of the geologic characteristics of the study area, this paper studied the sedimentary facies of different wells on the bases of fine stragraphic division and correlation. This paper also studied the tectonic characteristics by means of fault interpretation and horizon interpretation on the bases of the seismic geology horizon calibrating. Finally, the paper studied the reservoir characteristics, and classified the reservoir to three types, meanwhile, considering the reservoir distribution and hydrocarbon accumulation patterns of the study area, this paper also evaluate this study area considering different sublayers and different regions, pulling out five favorable target wells.Shishen 100 area is a large scale orward direction nose-structure, which dipped to the southwest and upheave to the northeast. The tenth sand group on the second member of Shahejie formation can be divided into ten sub-layers, and the sedimentary environment was delta, which was mainly consisted of delta front subfacies and prodelta subfacies. The reservoir in this area is low-porosity and permeability rock, with the mean porosity 8.726% and the mean permeability 4.89×10-3μm2.Comprehensive several factors affecting reservoir, the study classified the ten sub-layers into three types:5~8 sub-layers are type I, while 4 and 10 sub-layers are type II,and 1~3 and 9 sub-layers are type III. This classification coincided well with the production data of the oil field. The type of oil and gas reservoirs are lithologic, structural-lithologic composite oil reservoirs in this area, and the oil reservoirs did not have unified oil/water boundary. Sand body, fault, structural setting and sedimentary facies have great influence on hydrocarbon reservoir-forming and distribution. Based on the comprehensive reservoir evaluation, this study proposed five favorable target wells.