Carbonate reservoir classification and gas reservoir identification in lower Palaeozoic of Ordos basin

Based on logging data analysis of electric imaging,the carbonate reservoirs in Ordos basin can be divided into karst holes,cracks,solution pores-fracture and cave,the cavefractured-vuggy 5 classes reservoir,and the summarization on the conventional logging response characteristics of the five kinds of reservoirs have been made.The analysis results indicate the gas-bearing characteristic of solution pores and solution pores-fractured- vuggy reservoir hydrocarbon content is the best.Aiming at the difficulty of gas reservoir identification in complex carbonate reservoir pore structure,four kinds of identification methods have been provided.The application effects indicate the identification ability of the single factor gas logging crossplot parameters is limited,while the composite parameters crossplot can accurately identify the atmosphere,and therefore,it is of further popularization and application.