Drilling used to be hit or miss. Operators hammered cable tools into the earth, hoping to find oil or 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 effectively 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.
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 safely 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 March 2010. Tethered in nearly 8,000 feet (2,438 m) of water, Perdido is the world's deepest offshore oil and gas drilling and production spar.
Investing in New Finds
As of 2011, 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 are being planned in several test areas, including the North Atlantic Margin offshore the United Kingdom, the east coast of Canada and deepwater Brazil.
Our technology and expertise enable us both to drill successfully, especially in deep water, and to create significant savings through reduced drilling time.
Setting a New Standard for Drilling
Chevron has set a new standard for directional drilling with the AutoTrak™ steerable rotary system. The system is controlled remotely by an aboveground operator who steers it by computer. The operator sends commands that direct the drilling operation and receives real-time log data about the oil-bearing rock. This enables the drilling tool to be steered in even the most complex environments.
Case in point: When the Captain Field was discovered in 1977, it was estimated to contain more than 200 million barrels of heavy crude oil. But despite its rich reserves, this U.K. North Sea field was deemed uneconomical to develop.
Fast-forward 20 years to 1997. With advancements in technology that made drilling long-reach horizontal wells an option, the first of three development phases for the Captain Field was launched. The initial production phase began that year.
Now in its third phase, the field has seen some notable "firsts" over the course of its development. Among these was a previously untested well design—a high dogleg directional well that turns and twists through a spaghetti junction of horizontal wells to reach its target: the previously inaccessible crude directly below the drilling platform.
In the summer of 2004, AutoTrak was used to drill and complete the first semihelical well—in and around 15 existing wells. The project demonstrated the tool's ability to precisely steer in a complex drilling environment with very little margin for error.
AutoTrak is just one example of how we are continuing to push our technology forward to safely find and produce oil and gas in remote, geologically complex areas.
Even as we find and start to produce from new wells, we still work to find ways to improve production efficiency. 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.
Updated: April 2012