Analysis of Shale Oil Productivity Difference in an 83 and Xi 233 Well Blocks in Ordos Basin

Abstract

The An 83 well block and the Xi 233 well block are both shale oil blocks in the Changqing Oilfield. The main producing layer is the Chang 7 reservoir, with strong heterogeneity and no obvious oil-water interface. Both are typical low porosity, Low permeability-extra low permeability reservoirs. The An 83 block and the Xi 233 block adopt the same volume modification method for production, but the output data of the two are quite different. The output of the Xi 233 block is significantly better than the An 83 block, and the water content is also lower. Finding out the reasons for the production differences and proposing a targeted shale oil reservoir volume modification model is the key to increasing the production of Block An 83. On the basis of the analysis of production influencing factors, it combines geological factors such as gamma, interval transit time, porosity, saturation, etc., geomechanical factors such as Young’s modulus, Poisson’s ratio, horizontal stress, and Engineering factors such as displacement, liquid volume, sand ratio, etc. Using Pearson and Spearman correlation analysis methods to clarify the main controlling factors of output and capacity, on this basis, complete the research on the output difference of the two blocks. The final results show that the physical properties of the two blocks are the same, the water content is quite different, and the geomechanical basis is different. It is necessary to formulate targeted reservoir transformation and production methods based on the pore throat structure, relative permeability and geomechanical distribution characteristics of Block An 83.