Research progress and development tendency of polymer drilling fluid technology for unconventional gas drilling

Unconventional gas includes tight sandstone gas, shale coalbed methane, and natural hydrate. With huge reserves, unconventional has become the most important resource successor after end of “Easy Oil era.” The drilling fluid is an indispensable wellbore working for with multiple functions. polymer (PDF) common, longest developed, diverse type. advantages easily controlled rheology, convenient on-site performance maintenance, specifically low cost weak environment pollution, PDF gradually replacing oil-based as first choice drilling. invention non-disperse low-solid-content in 1960s shows that technology entered stage scientific development, until now, its development generally experienced five stages: beginning, developing, improving, re-developing, re-improving. Dozens additives systems have been invented applied, which solved severe problems, greatly improved efficiency, promoted exploration difficult oil resources. This paper reviews research progress according to timeline by introducing composition, feature, advantages, disadvantages some representative systems, emphatically function mechanism stabilizing wellbores, lubricating tools, protecting reservoirs biomimetic wellbore-strengthening amphiphobic high-efficiency Then, combining future global demands, especially China’s strategic needs tendency critically illustrated several potential directions including intelligent PDF, ecological hydrate deep layer