Abstract:

It is an important problem of horizontal well geo-steering drilling to determine the up and down direction of bit marching and the position of the bit in the target formation. This paper introduced a practical method to solve the problem by using MWD and LWD information. Based on the geo-steering geometry theory, in terms of the relation between the formation dip angle and the angle of horizontal line to the line of two adjacent points on wellbore trace, This method can judge the bit up-down direction and determine the position by the distance of the bit from the top surface of target formation and comparing the logging curves with conventional cable logging curves from adjacent wells. This approach was applied to the practical drilling in three Horizontal wells, and then the geo-steering drilling ability was obviously improved and the result of following the tracks of geology target layer while drilling was obtained.

Key words: horizontal well drilling, target oil-gas formation, up-down drilling, measure and logging while drilling, geo-steering