In today’s low oil price environment, offshore operators, like their onshore counterparts, are looking to extend the profitable life of mature fields. Often, this requires drilling through salt, unstable coal and shale layers, tar zones, depleted zones, and formations with variable flows and pressures—and doing it safely, efficiently and economically. For many years operators were forced to compromise ideal well placement to avoid these troublesome formations, leaving millions of barrels of oil in the ground. More recently, techniques such as managed pressure drilling (MPD), casing while drilling (CWD) and liner drilling presented alternatives to conventional techniques to enable drilling through problematic zones to reach reservoirs that previously had been considered unreachable and economically unviable. Click the link below to read the full article.