GENESIS AND PETROPHYSICAL IDENTIFICATION OF RELATIVE HIGH PERMEABILITY OF SANDBODY IN SULIGE GAS FIELD, ORDOS BASIN

The key problem for developing the Sulige gas field with high efficiency is the identification of the relatively high permeability of sandbodies in low efficient gas reservoirs.In Sulige gas field,with the characteristics of typical coal measure strata,many primary pores have disappeared due to severe diagenesis.As a result,the relatively high permeable sandbodies are mainly developed in coarse sandstone facies with secondary pores.It is known that different log curves,such as density log and acoustic log,reflect different pore structure and lithofacies.Based on this,an interpretation model of secondary porosity index for the reservoir is established.After the calibration with the core lithology of key wells,the sensitive logs to lithology,such as GR,PE,and DEN are used to identify lithofacies by utilizing cluster analysis.The results show that the relatively high permeable sandbodies identified by this log interpretation model of secondary pores and lithofacies are consistent with core analysis and production capacity tests of gas wells.