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Artificial Lift Techbook 2016

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ARTIFICIAL LIFT TECHBOOK: TECHNOLOGY 20 | May 2016 | increased drilling effciencies. More sand downhole helps prop fractures open for longer. However, those improvements delivered a new set of challenges for production teams to manage in the remaining years of a well's life. In a fashion similar to the one patterned by drilling and completions teams, the technologies and techniques used by production teams are also evolving. Earlier and more open communication between the teams paired with new or improved technologies for challenges like sand is expanding artifcial lift applications considerably. Early planning In the beginning of what would become known as the "shale gale," it was common to hear tales of wells coming in with staggeringly high rates of fow. Also common was the bark of the naysayer pointing out the rapid drop-off of production shortly after the well was brought online. Like an agitated bottle of champagne, once its cork was popped and its bubbles bubbled out, unconventional wells were left needing a lift option far earlier in life. "In conventional production from vertical wells the production declines gradually over time such that lift selection can be delayed and the best lift to use is usually fairly obvious. Also, the well geometry is fairly uniform and easy to work with," said Bill Lane, vice president of emerging technologies for artifcial lift systems at Weatherford. "However, in unconventional production, lift selection is more challenging. Production rates can be highly variable and are characterized by slugging of gas and liquids. Lift systems must be able to han- dle signifcant amounts of gas, including long gas slugs. Hydraulic fracturing of low-permeability shale results in high initial production rates followed by a rapid decline in production. Therefore, lift systems must either be fexible and capable of operating eff- ciently over a wide range of production rates, or lift systems must be easily resized or replaced. "All of that needs to be considered upfront, during the well-planning stage, rather than as an afterthought. The wells can require artifcial lift within three to six months of initial well production, sometimes even sooner," he said. "It usually makes sense to go ahead and have the artifcial lift system in place, rather than having to come back on the well within a few months of the commissioning." The need for earlier involvement in feld devel- opment planning was seconded by Neil Griffths, business development manager for artifcial lift technologies for Schlumberger. "Wells must be designed, drilled and completed with their life cycle of free fow production and inevi- table artifcial lift in mind. Often this is not the case," he said. "All feld development plans should include artifcial lift considerations and, wherever possible, the wells should be designed from 'inside out' to accom- modate them—frst the ideal completion and then casing design. Again this is often not the case," he said. "Typical shortcomings and compromises include casing or liner size and wellbore trajectory. The old adage of 'drillers and well engineers have love affairs with wells, whereas production engineers are mar- ried for life' is as true now as it ever was. Examples include 7-in. and smaller casings limiting artifcial lift selection, where 7-5/8-in. casing would offer so much more opportunity," he said. "Also wells drilled too quickly result in tortuous wellbores that cause problems with pump oper- ations throughout well life, for example, rod or tubing wear, pump or cable damage, bent shafts, and reduced run life." Building straight According to Lane, deep unconventional wells often require long artifcial lift pumps that are incompat- ible with high deviation build rates, adding that some operators are building in straight tangent sections within the build section in order to have a straight section in which to land the lift pump. The formation of multidisciplinary teams to tackle tough challenges has become more common as the need for collaboration across disciplines has become more accepted within the industry. That approach can help infuence how wells are con- structed to result in greater recovery, according to Jonathan Nichols, unconventional market segment manager for Baker Hughes. "ESP systems have to operate in a relatively straight area, but the deeper you can get in the well and the closer you can get to the producing zone the more reservoir pressure draw is going to be

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