Logging identification and application of lacustrine dolomite in the fourth member of the Shahejie Formation in the Bamianhe area of Dongying Sag
The rock composition and structure of lacustrine dolomite reservoirs are complex and diverse,and the use of logging data is of great significance for identifying dolomite lithology.In order to solve the problems of heavy workload and low recognition accuracy in traditional logging methods,a method of integrating spider web plot intersection plot principal component analysis is proposed to construct a lithology sensitive factor intersection plot and carry out comprehensive identification of lacustrine dolomite lithology.The results indicate that:(1)The fourth member of the Paleogene Shahejie Formation(Sha 4 Formation)in the Bamianhe area of Dongying Sag is mainly composed of granular dolomite,microcrystalline dolomite,mud crystalline dolomite,sandstone,and shale.Among them,granular dolomite,microcrystalline dolomite,and shale are the main rock types.(2)Selecting 6 types of feature parameters to analyze the differences between spider web diagrams and intersection diagrams of different rock types,among which GR and AC can effectively distinguish granular dolomite,and SP has a good distinguishing effect on sandstone.Based on the results of spider web diagrams and intersection diagrams,principal component analysis is applied to standardize the logging parameters,and principal components F1 and F2 with a cumulative variance contribution rate of 90.75％are constructed.A lithology discrimination model is established to comprehensively identify lithology.(3)Through the verification of production capacity and coring wells,the accuracy of lithology identification is as high as 85.4％.It is clear that the granular dolomite is distributed in a strip like pattern in the west along the SW-NE direction,transitioning to microcrystalline dolomite and mud crystal dolomite in the south and north,while irregularly distributed sandstone is dominant in the east.This fusion method can efficiently identify the lithology of dolomite and has strong guiding value for subsequent favorable reservoir evaluation and oil and gas exploration.
lacustrine dolomite reservoirlogging identification of lithologySpiderweb diagram methodprincipal component analysis methodfourth member of Shahejie Formation(Sha 4 Formation)PaleogeneBamianhe areaDongying Sag
万方数据
维普
