Characteristics And Origin Of Dolomitic Rocks And Reservoir Controlling Parameters On The Fengcheng Formation From Wuxia Area, Junggar Basin

Recent years exploration practice indicates the exploration prospect of dolomite reservoir of Fengcheng formation in Wu-Xia Area, Junggar basin is extremely optimistic.Although many progresses have been achieved in the research of rock types, types of deposit environment, dolomite genesis and controlled factors of reservoir, much divergence still exists. This paper in inherits the predecessor research results, based on core and flake observation and test data.By means of energy spectrum analysis, flake analysis and X-ray analysis. Combined with geological information, by applying the methods of macroscopic survey and microanalysis, we have investigated in detail of rock types, types of deposit environment, reserving space types and dolomite genesis and controlled factors of reservoir, built up reservoirs forming mode. Based on geologic analysis, the favorable reservoirs of Fengcheng formation can be predicted by comprehensive treatment information of well-log and seismic information. After systematic research, this paper has made the following achievements:Shortite and wegscheiderite was first discovered in Fengcheng formation, the mechanism of formation and distribution of these salt mineral was sort out and their sedimentary models were established; Seismite was first discovered in Fengcheng formation along with sedimentary structures and set up a seismic sequences; Exhalative rock was first discovered in Fengcheng formation along with many microstructures and shows pulsating tectonic movement in Wu-Xia Area; In inherits the predecessor research results, based on rock types, closing conditions of lake, Pale ontological information and geochemistry study, there was a residual oceanic basin during Fengcheng formation period. The dolomites of the Fengcheng Formation are divided into peneprimary dolostone and secondary dolomites. The metasomatic mechanism of secondary dolomites possesses important theory significance. Rock types, distribution characteristics of the cracks and high pressure, salt mineral occurrence play very important role in controlling areas where favorable reservoirs developed.These results have great theoretical meaning to research of genesis of dolomite and possess important petroleum exploration meanings of Fengcheng formation in Wu-Xia Area...