TULSA , OK— A new Department of Energy-funded technology has demonstrated the capability to dramatically reduce costs and improve safety and efficiency in drilling America's oil and natural gas wells.
Slider LLC, Houston, Texas, is now seeking to commercialize the technology, which overcomes the shortcomings of conventional drilling systems used to directionally drill oil and natural gas wells.
Directional, or "slant," drilling simply refers to drilling non-vertical wells for a variety of reasons, such as accessing a subsurface reservoir at an angle because it lies below an off-limits site or exposing more of the targeted formation to the wellbore. It is accomplished primarily with either a rotary steerable system or with a conventional steerable mud motor in tandem with a measurement-while-drilling (MWD) system:
- A rotary system is designed to drill directionally with continuous rotation of the drill pipe from the surface, which eliminates the need to slide the drilling motor along the borehole. Rotary systems are highly efficient and make for a smooth wellbore but they are extremely costly, thus ruling them out for most onshore and marginally economic offshore wells.
- A mud motor uses the hydraulic horsepower of drilling fluids to drive the drill bit, while an MWD system helps the driller monitor various drilling parameters, such as angle and ROP, during drilling. Steerable mud motor/MWD systems are affordable but often bog down in the "sliding" mode when the pipe becomes sticky.
Directional drillers often use a rocking motion (turning the pipe to right and left) to reduce drill pipe stickiness and improve ROP. Commencing a slide and reorienting the tool face invariably entails costly rig downtime and increases the risk of wellbore failure during such an intervention.
The Slider technology, originally developed at Noble Corp., Sugar Land, Texas, overcomes the shortcomings of steerable motor/MWD systems used in directional drilling by automating the rocking motion during sliding. The new, patented tool controls torque from the surface with a combination of robotics and innovative software that integrates surface and downhole data to automate the rocking motion during sliding. The system works over a wide range of pipe-rotation equipment; no equipment is added downhole.
After developing a laboratory-scale physical simulator and conducting initial field tests, Slider LLC sought to extend the technology beyond initial field tests that involved a basic hydraulically powered swivel. Through its National Energy Technology Laboratory, the Energy Department helped fund a Drilling Engineering Association joint industry project that called for—
- Modifying the Slider software to accommodate electric top-drive drilling systems (the new standard for drilling efficiency).
- Building a two-robot system and testing related robot software.
- Conducting at least three field tests to validate the technology on electric top drives.
- Documenting the cost-effectiveness of the technology.
- Developing a new computer torque-and-drag program that incorporates the rocking effect.
In addition to completing these tasks, Slider LLC built a plug-in interface that eliminated the need for robots, trained directional drillers for the field tests, and analyzed the results from the three field tests.
The improved Slider technology increased ROP, reduced drilling time, and almost eliminated stalling, thus extending motor and drill bit life. Field tests in Texas oilfields showed that the system increased ROP by 60-200 percent for estimated savings of 11-23 percent of total well costs.
America 's oil and gas production continues to decline, even as demand for both continues to rise, increasing U.S. dependence on imported supplies. Meanwhile, service/supply costs have skyrocketed in a severely capacity-constrained industry.
To tackle the job of recovering more oil and gas in the current business environment, producers need every efficiency and cost advantage they can find. Significant well cost savings such as the Slider technology provides thus offers an opportunity to enhance the Nation's energy security.