Dominant sand body distribution and geologic sinificance of Chang8_1 formation of ML area

Aimed at the problem that the sand body of Chang81formation in the ML area has inferior lateral continuity,various changes in vertical,and its extended direction is predicted difficultly,Chang81formation is divided into three small units and the dominant sand body that is the biggest continuous thickness and high extent of well logging curves in the small unit is chose as the research target to predict the planar distribution subtly in order to enhance the veracity by decreasing the shortages that the accumulative thickness of sandbody can increase effective thickness and that different sandbodys connection can expand distribution area.The result indicates that there are nine branches of sand strips,with the two from the west provenance as the same time the others from the west-south provenance,and the simple sand strip is about 1~2km wide,while the width of the converging area is 4~5km and the average thickness of main sandbody is 7~9km,and every strip is different extent and dimension in different periods and the zone whose sand thickness is beyond 4meter is advantageous area,of which Chang831is the most biggest.The result offers the proof of the west provenance and confirm the reservoir size and the deploying purpose formation is aimed directly at the dominant sand body to decrease the risk.