A new cross plot for identifying low resistivity reservoirs and its application

A low resistivity reservoir identification method of thickness-resistivity cross plot was presented on the basis of the recognition of the effect of sand thickness on the low resistivity reservoirs of North Jiangsu Basin.First according to the distribution of thickness and resistivity,thickness-resistivity cross plot,by which envelope of oil layer and water layer can be determined,was made,and the thickness and the upper and lower limit of resistivity of the low resistivity reservoirs were provided.Then combined the artificial nerve network method,further discrimination was taken to the oil layer,water layer and dry layer of the low resistivity reservoir.By this method,the low resistivity reservoir was discriminated in member 3 of Funing formation in the 7th fault block of Shanian Oilfiled in North Jiangsu Basin.The results show that the ability of identifying the low resistivity reservoir was improved effectively and the coincidence rate of log interpretation was enhanced.By the identification method,another 12 low resistivity oil layers were found in member 3 of Funing formation in the 7th fault block of Shanian Oilfield of North Jiangsu Basin.This shows that the identification method can obviously enhance the economic benefit of Jiangsu Oilfield.