Publications

A new hole cleaning process applied in Venezuela’s PDVSA Heavy Oil Drilling Project, in the Orinoco Belt, saved 3 rig days and reduced stuck-pipe and avoided damage to the MWD/LWD Bottom Hole Assembly (BHA) and drill bit. A long sought solution for effective hole cleaning was validated. Applied the first time, this concept provides a novel integrated solution for hole cleaning, is transferrable to other Well Construction projects, reducing project costs, lost-in-hole BHAs and significantly reduces flat drilling time & invisible lost time. Hole cleaning is the main challenge of any deviated drilling operation, with problems in cuttings and cuttings beds removal. Even optimized mud flow rates, with reciprocal and rotational pipe movements physically cannot completely remove cutting beds. The solution constitutes to incorporate a scraper into the drill string, applied together with an engineered hole cleaning process. With no access to dedicated casing cleaning tools, the 9 5/8" casing was cleaned from cuttings by back-reaming inside the casing with the BHA drill string, requiring minimum 2-3 runs and 2 days, and causing excessive wear on casing, BHA and PDC bit. After drilling the 8 ½” section, the concept was to place a scraper assembly into the drill string, allowing only minimum POOH of DP stands as part of the scheduled openhole wiper trip activity, followed by RIH back to TD – and as such completing the openhole wiper trip. The tested solution eliminated all back-reaming inside casing and ensured a full 360° casing contact cleaning prior to RIH the liner, guaranteeing the casing is free of cuttings and also eliminating any additional “Round Nose Mill” trips. The scraper never moved outside the casing. This first application of RIH a Scraper as part of the drill string gave outstanding results with 3 days been saved and a smooth RIH of the liner.