Drilling used to be hit or miss. Operators hammered cable tools into the earth, hoping to find crude oil or natural gas. But development of more sophisticated tools has enabled drillers to probe greater depths with more success in less time. Since the remaining hydrocarbons are more difficult to access, the search for oil and gas is constantly leading us into deeper waters and more remote terrain. Developing and using the most advanced technologies is critical for success.
Until the 1970s, rotary drilling was sufficient. Then experts realized that vertical wells alone were not enough to tap the full potential of reservoirs. So horizontal drilling was developed to enable access to areas of reservoirs that were previously unreachable, thereby increasing production. More recently, the same concept has been pushed further with great results: Directional and extended-reach drilling have allowed operators to access reservoirs far from the drilling location.
Completions technology also has evolved, helping to secure wells in less time and with greater protection. Cased-hole completion involves making small holes in the well casing and formation so that oil or gas can flow into production tubing. Open-hole completions are another option: Sand screens and gravel packs are inserted into the reservoir to stabilize the hole and maintain the flow of oil from the reservoir into the well bore. This process controls the migration of sand to avoid washouts and other problems.
Next, acids and other fluids can be pumped into the well under high pressure to fracture, clean and stimulate the rock to produce oil or gas. Finally, production tubing is added to provide an efficient path to the surface.
Chevron has successfully developed and deployed a new completion system that can save significant time and cost in deepwater developments. The system, installed in the deepwater Gulf of Mexico in 2012, enables the operator to stimulate and gravel pack multiple production zones in a single trip, and is designed for use in deepwater and ultra-deepwater offshore completions. Deploying in a single run allows more of the reservoir to be stimulated in a shorter amount of time, which increases efficiency, reliability and production.
The Chevron deepwater team successfully ran the completion to a depth of 27,945 ft. (8,517 m) from the water surface.
What Chevron Is Doing
Chevron's long-term exploration strategy—which blends disciplined, data-driven decision making with superior technical competency—is paying off.
- Angola – The Benguela Belize–Lobito Tomboco production platform stands 1,680 feet (500 m) high and is one of the tallest structures in the world. It is the first compliant tower installed outside the Gulf of Mexico. Compliant tower platforms are attached to the seafloor, but are able to flex with the constant forces of wind, waves and currents. The platform's state-of-the-art rig can drill wells in excess of 30,000 feet (9,144 m).
- Kazakhstan – Tengizchevroil's Sour Gas Injection/Second Generation Plant uses a unique combination of conventional and newly developed sour-gas injection technology to process crude with a very high sour-gas-to-oil ratio. Sour gas is natural gas that contains chemical impurities, notably hydrogen sulfide. This project may pave the way for applying the technology more broadly within the Tengiz reservoir, with the potential to increase recoverable reserves.
- Nigeria – The Agbami deepwater project uses a floating production, storage and offloading vessel to produce oil in 4,800 feet (1,463 m) of water. The project's subsea wells, completed using intelligent well technology, are some of the most complex in the world.
- United States, Gulf of Mexico – The Perdido Development began production in 2010. Tethered in nearly 8,000 feet (2,438 m) of water, Perdido is one of the world's deepest offshore oil and gas drilling and production spars.
Investing in New Finds
As of 2012, Chevron was one of the world's more active offshore operators. Key exploration areas are the U.S. Gulf of Mexico, the deep waters off western Africa and offshore northwest Australia. Drilling and seismic activities occurred or were in various stages of planning in several other areas, including Argentina, the east coast of Canada, China, central Europe, Indonesia, the Kurdistan region of Iraq, Liberia, Morocco, Suriname, Thailand, Vietnam and offshore the United Kingdom.
In addition to preparing new oil and gas wells for production, drilling teams also revitalize existing wells. This process involves repairing or stimulating the well—such as replacing the tubing or deepening the well—to restore or enhance its production of oil or gas.
Continued investment in drilling and completions technologies is important as wells become deeper, longer and more geometrically complex, and as we extract resources from challenging rock formations.
Updated: June 2013