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The Technology: Modern Alchemists
The Science of Success
By Cheryl Hudak
In ancient times, alchemists labored to turn metal into gold. Today, a group of modern day alchemists is using new-millennium technology to transform Chesapeake’s resource base from one almost totally dominated by natural gas into a liquids-rich asset mix that will significantly enhance the company’s already strong profitability and increase its returns on invested capital.
Lab Technician II Greg Ledbetter with a flat of shale
This effort is uniting the talents of Chesapeake’s petrophysical team with those of researchers in the company’s proprietary core analysis laboratory. The collaboration extends far beyond the lab however, to include Chesapeake’s geoscience and engineering technology groups as well as land, drilling and production teams.
The liquids-rich targets being sought by Chesapeake range from natural gas that contains heavier hydrocarbons such as ethane, propane and butane (which condense out of the gas at the surface to form condensate), to liquid gases such as pentane, and on up the hydrocarbon scale to petroleum, commonly known as crude oil.
While the company’s move to refocus much of its drilling activity from natural gas to liquids-rich resources may have taken some observers by surprise, it has been under consideration for years, according to Steve Dixon, Executive Vice President – Operations & Geosciences & COO.
Photo reveals shale in a new light:
layers of bentonite ore inside a
Niobrara formation core sample
fluoresce under black lights.
“We’ve been working on oil shale cores for a long time,” said Jeff Miller, Vice President – Geoscience Technology. “We started developing our acreage positions and procedures for developing liquids-rich plays for four years before we talked about it. That’s because it is a challenging enterprise.”
In the past half decade, while Chesapeake was successfully establishing itself as the standard setter in finding, developing, monetizing and producing unconventional gas plays, the groundwork was quietly being laid for achieving the same leadership in unconventional liquids-rich plays.
Much of that groundwork has taken place in the Reservoir Technology Center (RTC), a state-of-the-art research facility that has analyzed more than 28,000 feet of rotary core samples since it opened in April 2007. In three years the RTC has grown to include a second laboratory and two warehouses that preserve the thousands of feet of core samples, organized into a searchable database for easy access when they are needed.
A close-up of the brilliantly colored
“We now build our own equipment and software,” said Don Harville, Manager – Reservoir Technology Center. “And we are analyzing data in a way that no one else we know can do. We are taking things to a new level.”
The group collects data by analyzing core samples, rock displaced by the drilling process when a rotary drill grinds its way into the earth. State-of-the-art tools enable them to learn critical details of what to expect from a well; they use thermogravimetric analysis (TGA) to measure minute weight loss amounts when a substance is heated, which allows them to evaluate petroleum source rocks. Another tool measures rock permeability by analyzing pressure decay.
“There are a lot of challenges,” Harville said. “Gas permeability is easy to measure. Oil, on the other hand, is more challenging. It is a totally different creature down below than it is at the surface atmosphere.”
Oil samples from the Woodford,
Eagle Ford and Bone Spring
plays also fluoresce yellow under
black lights. The lighter the
yellow fluorescence, the lighter
the oil and the more mature the
sample. Condensate (wet gas)
does not fluoresce.
Unconventional oil is the same substance as the oil produced by conventional vertical drilling; the difference is that it is found in shale or very tight rock environments instead of the much more porous, permeable sandstone-type reservoirs which can be produced by conventional methods. Until the advent of horizontal drilling and multistage fracture completion techniques, unconventional oil recovery and production was not economically attractive. It is still not a simple process.
“It is hard enough to get gas through such a very small pore system,” said Miller. “But the margin for error is even less for oil. It is a real challenge.”
Fortunately, this team thrives on challenge – and on the collaboration required to meet the challenge.
“The RTC would be just another lab without the expertise of Alan Byrnes, Chief Petrophysicist, and Lesley Evans, Manager –Petrophysics, and their team,” said Harville. “Our scientists in the RTC know the importance of the data. But it’s our petroscientists who take that data and make it sing.”
Senior Geologist Steve
Chipera in Chesapeake’s
Byrnes has been studying the nature of rocks and reservoirs for decades. The company’s core petrophysicists study the core sample measurements obtained by scientists in the RTC, while log petrophysicists interpret wire line log measurements taken by tools inserted in a drilling borehole. Integrating all that data reveals meaningful information that helps predict total reservoir performance, and maps the nature and distribution of each reservoir’s properties.
“Combining all these measurements with geology, geophysics and engineering gives us valuable clues about where and how to drill,” said Byrnes. “We put all the parameters into a large-scale model that allows us to predict reservoir production and ultimate recovery – and the best completion techniques to maximize recovery and production on each well.”
The payoff for all this study and effort is the higher market value of liquids-rich resources compared to the price of natural gas. The heavier the hydrocarbon level of the asset, the higher price it commands. Another big plus is, to get through those very tight rocks, unconventional oil is usually very light and sweet – from 30 to 60 API gravity (an industry measure of density). That is highly desirable, as well as profitable – because light oil produces a higher yield of gasoline, and sweet oil is more environmentally friendly, requiring less refining to meet sulfur standards.
Blurred by the strong winds of the northern Great
Plains, a flag marks the future site of the
Wagonhound 14 1-H well in Converse County,
Wyoming, just over a ridge from the drillsite of the
Wagonhound 13 1-H. In the background lie the
Laramie Mountains, marking the eastern edge of
That’s the big difference between the ancient and modern alchemists – the alchemists of old never found the secret of turning metal into gold. Chesapeake’s modern alchemists are helping the nation’s most successful natural gas driller transform its asset base into gold for investors while providing a domestic fuel source for an energy-hungry America.
“Combining all these measurements with geology, geophysics and engineering gives us valuable clues about where and how to drill.”
Geologist – a scientist who gathers and interprets data pertaining to the rocks of the earth’s crust and the processes that created them
Petrophysicist – a scientist who studies the nature of rocks, their physical and chemical properties, primarily with the use of well logs and cores
Liquids-rich resource – natural gas that contains a higher concentration of hydrocarbons than dry natural gas (methane). Along with dry gas, natural gas liquids (NGL) and condensate are produced. NGL include propane, butane, pentane, hexane and heptane. Because they have higher hydrocarbons, they have higher energy levels, so they command higher prices in the market than dry natural gas. These higher prices add significant value to a well, a play and a company.
Well logs – detailed records of the geologic formations penetrated by a borehole, often gained by lowering instruments into the hole during the drilling process
Core sample – a cylindrical section