Study on the Applicability of a New Type of Bit in Ordovician - Cambrian Dolomite Formation of Tarim Basin

Abstract

Abstract The Ordovician-Cambrian reservoirs in Tarim basin are characterized by complex geological structure, deep reservoir, and thick dolomite strata in the middle and deep formation. The dolomite formation is characterized by large content of chert, high dense lithology, high uniaxial compressive strength, prominent impact and heterogeneity of the formation, it was difficult for conventional drill bits to form stable effective cutting depth and prone to vortex damage, which leads to short drill footage, low ROP and long drilling cycle, it seriously restricted the efficient exploration and development of Cambrian subsalt reservoirs in this block. Therefore, experimental analysis of rock mechanics in the Cambrian dolomite formation was carried out to quantitatively evaluate the rock mechanics properties in this area. A new type of PDC bit was designed to improve the impact resistance and eddy resistance of single teeth, and the impact fatigue test was carried out and successfully applied in the field. The research results show that compared with the adjacent wells in the same interval and lithology, the footage is increased by 39%, and the ROP is increased by 84%, which has achieved obvious acceleration effect, providing technical reference and support for the efficient exploration and development of Cambrian pre-salt reservoirs in the Tarim Basin.