ROP Improvement Techniques Applied in Well Yangtan 1 when Drilling into a Deep Buried Hill

During the drilling of Well Yangtan 1 in a deep buried hill, some technical difficulties were encountered, such as poor drillability, abnormal-pressure, sidewall instability and well deviation. In order to solve these problems, studies were conducted on ROP improvement to increase drilling speed and accelerate exploration process. Based on the stratigraphic characteristics and technical difficulties, a series of ROP improvement techniques were comprehensively developed, including casing program optimization, well location shift and directional whipstocking, PDC bit design and selection specially for deep Paleogene, easy pressure control drilling, and polyamine potassium chloride drilling fluid. After this system was applied in the field, the drilling target was reached smoothly, with average hole diameter enlargement rate 1.8% in the third section of drilling. And compared with the adjacent wells, there was noticeable improvement in drilling speed, with efficiency reduction from 5.4% to 0, average ROP increase by 39.86%, drilling cycle reduction by 40.20%, and hole construction cycle reduction by 44.19%. It indicated that ROP improvement techniques used in Well Yangtan 1 in deep buried hill were effective to achieve optimal and fast drilling in deep buried hills in the Raoyang Sag and worthy of wide applications.