Discussion on a New Calculation Method for Missing True Formation Thickness - A Case Study from YM32 Area in Northern Tarim Basin

Abstract

The true formation thickness missed in the geologic borehole has important sense for understanding the strata of borehole and position of target layer. Nevertheless, there had not been enough effective technologies and calculation methods to calculate the missing true formation thickness at present. To solve this problem, this paper focuses on mathematical formula combining with the actual geological conditions, collects various useful geologic data and parameters, such as stratigraphic dip, dip direction, distance from drilling well to formation’s pinchout boundary along the dip direction and difference in height between drilling well and pinchout boundary, sets a reasonable calculation method, derives a complete set of new expression to calculate the missing true formation thicknesses. The typical region, YM32 Area in Tarim Basin, was taken as the case study to prove the accuracy and practicability of the calculation method. The result was inspected by the actual data of neighbor boreholes.