Horizontal wells are now more common in some areas of the world than traditional vertical wells. That is because they allow operators to develop reservoirs that would once have been impossible for economic or technical reasons. Additionally, nearly all wellbores used to exploit unconventional resources are drilled horizontally. By the end of 2012, about 76% of all wells being drilled in the United States were horizontal and high-angle.
Much of this activity is due to recent advances in technology that inspire operator confidence in their ability to drill these complex wells. However, the ability to extend drilling length and steer the bit can still end in disappointing results if the wellbore is not optimally placed within the target zone.
To increase operator ability to optimally place their wellbores, the industry has devoted significant time and resources to develop techniques to accurately steer the well with respect to reservoir boundaries while drilling.
An article in the Spring issue of Oilfield Review, “Structural Steering—A Path to Productivity” describes how structural steering—a method by which operators direct horizontal and high-angle wellbore trajectories—integrates data from deep-reading LWD resistivity tools and high resolution imaging devices to create structural models of the geologic conditions encountered by the drill bit. The technique allows drillers to correct wellbore trajectories in anticipation of structural changes ahead of the bit and helps operators better understand the formations already drilled.
Examples from a gas storage project in Italy, an unconventional reservoir in the United States, and a thin carbonate in the Middle East demonstrate how operators are optimizing well placement and more effectively accessing reservoirs and resources.
Read the full article at the Oilfield Review Web site.
Amer A, Chinellato F, Collins S, Denichou JP, Dubourg I, Griffiths R, Koepsell R, Lyngra S, Marza P, Murray D and Roberts I: “Structural Steering—A Path to Productivity,” Oilfield Review 25, no. 1 (Spring 2012): 14–31.
Structural steering, which integrates data from deep-reading resistivity tools and high-resolution imaging LWD devices, is helping operators better understand structurally complex reservoirs and proactively optimize well placement.