America goes for increased oil yields
22 Nov 2002
Dotting the landscape of virtually every working oil field in the United States is the symbol of the modern-day oil industry - the ubiquitous rocking beam pumping unit.
But for many oil fields threatened with premature abandonment, the key to prolonging their productive life may be a new type of pump which is submersed deep into the oil reservoir where it can operate more efficiently and at lower cost.
This new generation of oil field pumping technology is the focus of one of two US Department of Energy projects recently selected as part of the agency's Advanced Technology Development by Independents oil research and development program. In the government co-funded project, Enerdyne, an Albuquerque, New Mexico oil producer will team with Pumping Solutions to test the new submersible pump in New Mexico's San Juan Basin.
The second project, also with an independent company, will test a new seismic surveying technology designed to locate underground oil-bearing formations often invisible to conventional seismic technologies. These subtle formations could hold up to 22 billion barrels of yet-to-be-discovered oil in the United States. Vecta Exploration, of Dallas, Texas, along with the Texas Bureau of Economic Geology, will test this new technology as they explore for oil-bearing deposits in the Williston Basin of North and South Dakota.
'Both projects are aimed at providing cutting-edge tools to America's independent oil and gas producers,' said Carl Michael Smith, the Energy Department's Assistant Secretary for Fossil Energy. 'With oil imports rising and the nation's energy security a continuing concern, new technologies like these offer ways for our own companies to find and produce more oil from our own fields.'
Independent producers, many with less than 50 employees, now account for nearly half the oil produced in the lower-48 States. Most operate so-called 'marginal' properties where the easy-to-produce oil has been previously extracted, in many cases by larger companies that have since moved overseas. In many of these fields, huge quantities of oil - in some cases as much as 95 percent of the original oil resource - remain in place, beyond the capabilities of conventional oil field equipment.
Putting the Pump in the Well
Rather than 'putting a well on pump' - the phrase typically applied whenever an oil reservoir no longer has sufficient natural pressure to flow oil up a well to the surface - the Enerdyne project will test the effectiveness of a new way to 'put the pump in the well.'
The submersible oil pumps developed by Pumping Solutions (PSI) in Albuquerque, are approximately 8 feet long, 3 inches in diameter and weigh about 90 pounds each. A unique feature of the PSI pump is that it will be suspended at the end of a stainless wire rope. Electric power will be sent to the pump through a cable banded to the wireline.
Other submersible pumps are typically attached to the bottom of rigid tubing and often require days or weeks to extract using heavy-duty derrick equipment. Suspending the pump on a wireline permits it to be deployed - and retrieved when necessary - in a matter of hours using a towable trailer with a portable winch.
Enerdyne hopes to show that the submersible pump can cut typical oil field capital and operating costs by 50 percent or more. The positive displacement, diaphragm type pump itself is less than half the cost of a conventional rod pump. It is much less expensive to operate, consuming about half the power of a conventional pump and requiring much less maintenance than a conventional surface rocking arm pump with its constantly moving parts. A PSI submersible pump recently completed a three-month test at DOE's Rocky Mountain Oil Field Testing Centre, operating reliably 24 hours a day, seven days a week.
Enerdyne projects that, if the submersible pump succeeds in reducing oil field costs, an additional 780 million barrels of oil from the Red Mountain Reservoir in New Mexico's San Juan Basin could be produced over the next 20 years.
New Seismic Technology
Vecta Exploration and its subcontractor, the Exploration Geophysics Laboratory at the Bureau of Economic Geology, will develop a new seismic technology to explore for subtle oil-bearing limestone reservoirs in the Williston Basin of North and South Dakota.
Seismic surveys - a technique in which sound waves are bounced off underground rock structures to reveal possible oil- and gas-bearing formations - are now standard fare for the modern petroleum industry. But today's seismic methods are best at locating 'structural traps' where faults or folds in the underground rock have created zones where oil can become trapped.
Conventional seismic surveys often overlook the more elusive 'stratigraphic traps' where oil can accumulate due to changes in the rock's character, such as its porosity.
Vecta Exploration's concept hopes to reveal stratigraphic traps by employing all four types of shock waves generated in a seismic survey.
Typically, a seismic survey uses artificial noise - in most cases, a heavy thumping - on the surface to radiate out shock waves that are reflected back from underground rock structures. By studying the echoes, petroleum geologists can calculate the depth and outlines of underground formations.
But conventional seismic surveys use only one of the four types of shock waves generated in the process - the compression or 'P' wave. The 'P' wave is adequate for locating structural traps but often fails to reveal stratigraphic traps.
Vecta Exploration's seismic technology, however, uses the 'P' wave plus the three other major types of shock waves - the horizontal shear wave ('SH' wave), the vertical shear wave ('SV' wave) and the converted shear wave ('C' wave) - to 'paint' a richer and much more revealing portrait of the underground rock formations. Expectations are that the combination of all four wave types will permit petroleum geologists to locate the elusive stratigraphic traps.
The results could be extremely important for future US oil exploration and production. According to the US Geological Survey, there may be as much as 22 billion barrels of oil yet to be discovered in the stratigraphic traps in the United States. In the Williston Basin alone, where Vecta will test the new seismic technology, as much as 411 million barrels of undiscovered and recoverable oil may exist in stratigraphic traps.