TECHNICAL WAYS TO IMPROVE THE RATE WHEN DRILLING DEEP AND ULTRA-DEEP WELLS IN SICHUAN BASIN

The geologic conditions in Sichuan area are very complicated, and so the drilling of deep and ultra-deep wells has disadvantages of low rate, demanding completion requirements, and high exploration and development costs. The low rate when drilling deep formations has severely limited the progress developing deep reservoir formations. Whereby herein the major technical challenges impeding the improvement of deep or ultra-deep well drilling in complicated Sichuan geologic conditions have been analyzed, and new measures to be adopted to improve the deep and ultra-deep drilling rate in Sichuan have been proposed based on the successful experiences on Well Longgang-1 and the current status quo of drilling technology at home and abroad. The measures include adopting gas drilling in shallow Shaximiao-Xujiahe formations, adopting composite drilling (PDM + rotary drilling + PDC bit) in medium-deep Leikoupo-Changxing formations, integration of new technologies and proven technologies, and optimization of casing program design, drilling equipment packaging, etc.