Comprehensive analysis of the Jurassic clastic reservoir rocks in the Qiangtang Basin,northern Xizang

The Jurassic clastic reservoir rocks in the Qiangtang Basin,northern Xizang are examined with the aid of the method of comprehensive analysis.Firstly,eight main parameters which have greater influence on the reservoir rocks are selected and the single factor evaluation is made.The selected parameters include qualitative parameters such as lithology,diagenesis and pore space types,and quantitative parameters such as reservoir thickness,pore space structure,porosity and permeability.Then weighting coefficients of individual parameters for reservoir evaluation are given according to their influence on reservoir rocks.Finally the scores for each section in the basin are calculated by using the method of comprehensive analysis.The results of comprehensive evaluation show that the best reservoir rocks occur in the eastern and middle parts of the North Qiangtang depression and the northern margin of the central uplift.The better reservoir rocks are in the western part of the North Qiangtang depression and the poor reservoir rocks are in the South Qiangtang depression.