Genesis Analysis And Evaluation Method Of Low Resistivity Oil Reservoir In Qikou Sag

Compared with the conventional reservoir,the low resistivity reservoir has strong secrecy and is difficult to distinguish on the logging curve,but it is found that its reserves and production can not be underestimated in the long-term practice.Because the regularity of reservoir in Qikou sag is not obvious,the formation structure is very complex,the lateral thickness changes greatly,and the oil-bearing property and lateral change of oil and gas reservoir are not clear.The genetic background of low resistivity reservoirs is also different.Multi genetic low resistivity reservoirs are widely developed.The identification and evaluation system of low resistivity reservoirs in this area still needs to be improved.This paper studies the distribution law of a large number of low resistivity reservoirs in Qikou Sag,and studies all layers in the work area by means of laboratory core analysis.It is concluded that there are four main causes of low resistivity reservoirs in Qikou Sag,namely clay additional conductivity,mud invasion,high irreducible water saturation and variable formation water salinity.According to the origin of reservoir,this paper puts forward a variety of identification technologies,including sedimentary rhythm correction technology,wavelet variable scale energy spectrum analysis technology,variable T2 cut-off nuclear magnetic resonance logging technology,automatic discrimination technology of interpretation chart,evaluation technology of fluid properties in brine mud environment based on logging logging information fusion and oil and gas reservoir identification technology based on big data cluster analysis.In addition,a quantitative evaluation technology suitable for the work area is also found.It has achieved good application results in the study area and improved the accuracy of logging evaluation.