Mechanical Analysis And Design Of Coring BHA In Long Horizontal Segment

The old field have lots of remaining oil, coring by horizontal wells is very important for the effective analysis of remaining oil distribution and the follow-up exploitation of oil fields. In this paper, three-dimensional finite element model has been established for the deformation analysis of the coring the bottom hole assembly (BHA). With the application of ANSYS software, large deformation and non-linear contact theory, the deformation analysis of the coring BHA at different profile has been analyzed, the length of coring tool was optimized for different curvature and this is a new research method for the throughout of coring BHA; Considered the conditong of BHA at coring, the model for the deformation analysis of the coring drill has been established at the base of many factors,such as bending equivalent stiffness of coring tools, the weight of full and empty cylinde, the gap and the contact state between drilling tools and the wall. At the same time, for the free contact and friction at different depth and different direction of the circumference, the " gap element of multi-contact and friction" and spatial beam element are applied to analyze with finite element for nonlinear mechanical problems for BHA .The contact state of BHA with the wall and the forces and the deformation of drilling bit is acquired. With the software"mechanical analysis and design for coring BHA at long horizontal segment, combined the oblique method of drilling tools an based on mechanical analysis of coreing BHA and the rusults of the whipstocking performance of the tools, 4 species of BHA have been designed and they are suitable for composite wheel and screw-driven coring operation to maintain angle , a slight decrease by single,the angle build by one stabilizer or two,the angle build by two stabilizers. The effects of the hole size, stabilizer outside diameter and other factors of whipstocking for drilling performance of the law is Calculated. Three kinds of BHA have been applied in xing 6-1 - ping 35 well, applying a total of 58 coring tube, the total footage coring 339.31m, the coring length 336.41m, the total harvest rate of 99.15 percent, the prediction accuracy rate of these coreing BHA in the horizontal well trajectory is 92.88 percent and this result fully meets the technical requirements of well path control when coring long length rock core in horizontal segment. It provides a reliable method of theoretical analysis and practical BHA for the BHA design when continued coreing long length rock core in horizontal segment.