Pengzhou 5-4D Drilling Fluid Technology

Abstract

Pengzhou 5-4D well is a three-spud directional well deployed by Southwest Oil and Gas company in yadehe structure, Longmenshan Piedmont structural belt, West Sichuan depression, Sichuan Basin. The designed vertical depth is 7545m, the designed maximum well deviation is 89.59°, the actual completed drilling depth is 7150m, and the completed drilling deviation is 91.58°. The strata encountered by the well are Penglaizhen formation, Suining formation, Shaximiao formation, Qianfoya formation, Xujiahe formation, Xiaotangzi formation, Maantang formation and Leikoupo formation. Potassium polysulfonate drilling fluid is used for the first and second spuds of the well, and oil-based drilling fluid is used for the third spud. During the second spud in, Ma’antang formation collapsed and fell seriously, making tripping difficult. After sidetracking, by adjusting the treatment idea of drilling fluid, making rational use of pre hydrated bentonite slurry, using asphalt with different softening points and nano plugging materials, the problem of collapse and falling blocks was well solved, and the operations such as tripping, electrical logging and casing running were safe and smooth. The white oil-based drilling fluid system is used in the third spud in a pioneering manner, and the construction is smooth without downhole complexity, which provides valuable experience for the construction of marine formation drilling fluid in Pengzhou block in the next step.