More on Exploration, Drilling and Production

More on Exploration, Drilling and Production

21st Century Exploration and Recovery
To maintain our high quality of life, Americans rely on steady and abundant supplies of petroleum products used in autos, homes, and business—averaging three gallons of oil a day per person.  In 2000, the petroleum industry produced 7 billion barrels of crude (1) using technologies that reflect a strong commitment to the cleanest and healthiest environment possible.

The task of finding new reservoirs of producible oil has become more challenging and complex.  In generations past, drilling for oil involved a massive operation that spanned acres.  It was hit and miss; drill a hole and cross your fingers.  Wildcatters with a small chance for success considered themselves psychics.  It was a messy business, with lots of unproductive holes and corresponding environmental damage.

Today, teams of geologists, geophysicists, and petroleum engineers carefully identify, characterize, and examine geologic prospects that hold the promise of yielding commercial quantities of oil and natural gas. Before a drill touches the earth, an array of advanced technologies are used to pinpoint—with a high degree of certainty—exactly where that drill should go. The drill itself is less intrusive and more precise, and the entire process is designed to minimize disturbances to land, vegetation, water, air, natural habitats, and surrounding communities.

Our world relies on oil and natural gas, and the vast processes involved in keeping it flowing, from discovery to consumer use, represents a series of adventures in energy.

Smart Discovery
The more accessible reserves in the U.S. have already been recovered.  Today’s productive onshore and offshore fields can be smaller, deeper, and less concentrated.  To meet the challenge of finding these hidden reserves, oil and natural gas exploration experts deploy sophisticated “smart discovery” electronic hardware and software to areas that seem to hold significant reserves.

Three-dimensional seismic imaging technology bounces acoustic or electrical vibrations off underground surfaces, generating massive amounts of data that produce multidimensional representations of those surfaces.  These data can be plotted on a detailed virtual map that allows explorers to identify areas where commercial quantities of oil and natural gas may have accumulated.  After careful analysis, an exploratory well can be drilled in the best spot, with a much better chance of success than a generation ago.

Four-dimensional time-lapse seismic visualization goes even further.  With this super-high-tech method, oil exploration detectives can capture three dimensional seismic data over time, providing a motion picture view of the flow patterns of oil and natural gas underground.  Flow patterns help reveal how to tap and manage the oil and natural gas reserve most efficiently, so that drilling, pressurization, and pumping are as minimal as possible. 

Advances in interwell seismic technology allow operators to take another look at older producing areas, such as oil fields in Appalachia, California, and West Texas, to discover potential untapped zones of oil and gas that were bypassed or could not be identified by seismic technology or the drillbit in the past.  In addition, improved computer-processing technology and interpretation software allow older seismic data to be reprocessed and reevaluated.

By using seismic imaging, as well as other available technologies, such as satellite-derived gravity and bathymetry, global positioning systems, and geographical information systems, today’s oil and natural gas explorers find much more while disturbing far less of the natural environment.  In API’s Adventures in Energy, you can learn more about “smart discovery” technologies.

Optimized Drilling
Just as smart discovery technologies result in more efficient exploration, optimized production technologies mean fewer oil and natural gas wells producing far more product.  Today’s drilling rigs provide versatile operation and create less waste than those of the previous generation.  Today’s rigs are smaller and highly efficient, and can be moved on trucks.  The bottom line for Americans is more domestic product to support our standard of living and greater security for our oil supply.  At the same time, increasing industry efficiency has reduced oil and natural gas production impacts to the environment.

In the past, oil and natural gas wells were drilled vertically at depths ranging from a few thousand feet to as deep as five miles.  But new directional drilling and horizontal drilling technologies allow drills to deviate from the vertical plane and go horizontal—or beyond.  For oil and natural gas producers, this means reaching reservoirs that are not located directly beneath the drilling rig, and avoiding sensitive surface and subsurface environmental features.

Advances in directional drilling now permit multilateral drilling, where multiple offshoots of a single wellbore radiate in different directions and can contact resources at different depths.  Development of this technology is recent and rapid, and promotes the use of one site instead of many sites.

At the same time, drilling away from the vertical plane has produced new challenges in extracting oil and natural gas from sophisticated drilling units.  Coiled tubing technology has helped the industry meet this challenge.  Coiled tubing is a continuous-length hollow steel cylinder of varying widths.  Stored on a reel, coiled tubing is flexible, contains no joints, and can be uncoiled or coiled repeatedly as needed.  Since a significant percentage of oil production takes place from costly offshore platforms, coiled tubing has proven to be especially economical. The equipment can be set up quickly, it runs at higher speeds, and it can work in existing wells.

But it isn’t just the direction of the drill bit that has been revolutionized.  Every time a drill bit enters rock below the surface, it displaces bits of rock called “cuttings,” which then become rubble.  Recent advancements in slimhole drilling have significantly reduced cuttings volumes.  As the name suggests, the slimhole drill is smaller and displaces less rock.  For example, a slimhole drilled to more than 2 1/2 miles in depth and ending with a 4 1/8-inch-diameter bottomhole produces one-third fewer cuttings than a standard well at the same depth.

Both coiled tubing and slimhole drilling enable less disruptive, quieter drilling operations, minimizing the noise for wildlife or humans near the well site.  Since coiled tubing is a continuous pipe, most noises associated with conventional drilling pipes are avoided.  Efficient insulation and the equipment’s smaller size further reduce noise levels.  For example, the noise level of a conventional rig from a quarter-mile away is 55 decibels (less than the hum of an air conditioner or the chirrups that insects make during summer nights), while a coiled tubing unit’s noise level at the same distance is just 40 decibels (27 percent quieter).  The smaller size of coiled-tube drilling also cuts fuel use and reduces gas emissions when compared with traditional drilling.

Smaller Oil Production Footprints
Environmentally speaking, any time a company erects an oil rig onshore or offshore, a certain surface area around that oil rig will be disturbed.  This area is called the oil rig’s footprint.  The footprint includes the production facility itself, plus housing, power, sanitation services for the workforce, and roads leading in and out of the area.  The production facility of today has been radically streamlined and occupies far less surface area when compared to operations 25 years ago.

Take Prudhoe Bay, Alaska, for example.  Estimated to contain 10 billion barrels of oil and 27 trillion cubic feet of gas, the Prudhoe Bay oil field is twice as large as any other oil field in America (2). The original production area developed in the 1970s wells spread over nearly 1,000 square miles. If Prudhoe Bay were to be developed using today’s technology, its footprint would be 64 percent smaller.

The key word regarding today’s footprint is small.  For instance, one development opened in 2000 in Alaska’s Alpine Field produces from a pad area of 97 acres—just 0.2 percent of the 40,000-acre field.  Directional drilling, zero-waste discharge, roadless development and other innovations were used to minimize the Alpine field’s footprint on the Arctic tundra.

New Processes to Minimize Waste
You might be surprised by how much water rises up from the ground along with oil and gas during extraction operations.  There’s a lot, and it’s known as produced water.  It’s considered a waste product and contains, among other things, volatile compounds, extractable organics (acidic, basic, neutral), ammonia, and hydrogen sulphide.  If not handled correctly, produced water can affect our overall water quality and the industry has long wrestled with what to do with this produced water.  The conventional approach involves pumping produced water and oil to the surface for separation.  The oil is pumped off and the water treated, then either reused in production operations or, more often, reinjected into the subsurface.  Bringing produced water to the surface incurs lifting and handling costs—25 to 50 cents per barrel for reinjection—$1.50 per barrel if the water must be removed by truck. 

The oil industry is rethinking conventional approaches in the quest to reduce the amount of water and avoid environmental impacts. Several new downhole separation technologies hold the potential of minimizing the environmental risks associated with produced water handling, treatment, and disposal.  All downhole separation methods involve the use of mechanisms in the wellbore that separate oil and water within the subsurface formation, eliminating the need to bring the water to the surface.  Downhole separation can cut produced water volume by as much as 97 percent, which greatly reduces the costs of lifting and disposing of produced water.

Protecting Wildlife Habitats and Preserving the Landscape
The U.S. oil and gas industry has integrated an environmental ethic into every aspect of business.  The industry actively collaborates with private conservation groups to protect sensitive coastal and marine habitats and wildlife.  For example, Shell Oil Company Foundation provided a five-year, $500,000 grant to The Nature Conservancy of Texas for conservation research and field-based environmental education programs at the Mad Island Marsh Preserve along the Texas Gulf Coast.

On Shamrock Island in Corpus Christi Bay, The Nature Conservancy of Texas and Bristol Resources are collaborating to restore and protect habitats impacted by past oil and gas operations. 

On Galveston Bay, ExxonMobil recently donated more than 2,200 acres of wetlands and grasslands for use as a preserve for the area’s wild prairie chicken, one of North America’s most endangered species.

Phillips Petroleum donated $1 million to the Alaska chapter of The Nature Conservancy in what amounted to the largest-ever corporate gift to environmental protection in the state’s history.  The Nature Conservancy Alaska chapter hopes to raise $10 million by 2005 for its “Great Places in a Great Land” statewide conservation planning project to review critical environmental habitats and purchase land or conservation easements to protect those habitats.

The Gulf of Mexico is an area of great interest to the oil and gas industry.  Here can be found a significant portion of U.S. oil and natural gas reserves; here also the industry serves as environmental stewards with an outstanding record.  For example, more than 120 decommissioned oil rigs in the Gulf have been converted into submerged artificial reefs in the industry’s “rigs-to-reefs” program.  These reefs provide living and feeding habitats for thousands of underwater species, enhancing the ecosystem of the entire Gulf and promoting tourism for the fishing and diving industries. 
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1 EIA, Petroleum Supply Annual 2000, Vol 1, p. 34

2 http://www.infoplease.com/ipa/A0108178.html

3 DOE, Environmental Benefits of Advanced Oil and Gas Exploration and Production Technology, http://www.fossil.energy.gov/news/techlines/1999/tl_envrpt.html