The Analysis Of Application Effect Of Non-planar Tooth PDC Bit Drilling Gravel Layer In Kuqa Piedmont

It is one of the key difficulties that extremely thick gravel layer distributed in the shallow and middle layers of the kuqa piedmont area in the Tarim Oilfield restricts the effective exploration and development of rich oil and gas resources in the area.The geological conditions in this area are extremely complicated.The maximum thickness of the gravel layer is more than 5000 m.The vertical and horizontal distribution of the gravel layer is irregular and Its drillability is extremely poor.In the soft to medium hardness homogeneous formation,the conventional PDC bit has very high rate of penetration with long service time,but in the process of drilling the gravel layer,the cutter are subjected to the strong impact of the gravel,which makes quickly the cutter caused breakage such as chipping,fracture and shedding of the diamond layer and then the rate of penetration is rapidly reduced.The conventional PDC bits have a very poor drilling effect in the gravel layer.Based on the mechanism of the conventional PDC bit breaking the gravel layer,the failure modes of the cutters are summarized and the breakage mechanism and the influencing factors of the breakage are studied when the conventional PDC bit drilling the gravel layer.The structural characteristics and mechanism of breaking rock of a triangular pyramidal non-planar cutting tooth are analyzed.Based on the finite element display dynamics simulation software LS-DYNA,the process of cutting rock with non-planar cutters is simulated,and the influence of different working angles on its impact resistance is discussed.A new non-planar tooth PDC bit designed for the optimization of the characteristics of the Kuqa Piedmont gravel layer has achieved good test results in the Boao block is studied.The feasibility of the bit in the gravel layer of the Kuqa Piedmont is analyzed.Through the above research,the non-planar tooth PDC bit is successfully tested in the gravel layer of the kuqa piedmont area,which provides an effective way and method for improving the drilling speed of the extremely thick gravel layer in this area,and broadens the application range of PDC bit.