2011 Workshop: Stimulation of Unconventional Oil and Natural Gas Liquid Reservoirs
Stimulation of Unconventional Oil and Natural Gas Liquids
(Updated 6/6/2011)
Third-Annual StrataGen High-Profile, Hot-Topic Workshop
Legend of Hydraulic Fracturing Speaks
StrataGen Engineering had the distinct honor of presenting Dr. Claude Cooke, a “Legend of Hydraulic Fracturing,” speaking at our 2011 workshop on April 27, and Cooke did not disappoint.
His talk, “The Invention of Hydraulic Fracturing, High-Strength Proppant and Other Old Stories,” was a fascinating discussion of hydraulic-fracturing history for the 110 workshop attendees from across the U.S. Cooke demonstrated how he championed the cause for intermediate strength proppants by crushing frac sand with a pair of pliers. He even proposed a national holiday, a “Hydraulic Fracturing Day.”
Cooke’s knowledge has advanced the technology of hydraulic fracturing for many years. In 1947, hydraulic fracturing was first performed in Kansas. Since then, hundreds of scientists like Cooke as well as many engineers and entrepreneurs have enhanced this evolving technology.
Cooke pioneered the development of the ceramic proppant used to fracture wells and has more than a dozen patents or patent applications for methods and materials used in fracturing. Overall, Cooke holds patents on 28 inventions.
For almost 32 years, Cooke worked as a scientist for Exxon Production Research, which is now ExxonMobil Upstream Research Company, in Houston. He performed and directed research in a broad range of technologies related to drilling and production, including oil recovery processes, natural gas processing, production logging, cementing and methods (such as hydraulic fracturing) for increasing the production rate of wells.
In a recent interview with TheMarcellusShale.com, Cooke recalled:
“In the mid-’70s, about 25 years after the first hydraulic fracturing treatment was performed in Oklahoma, I realized that hydraulic fracturing technology would be very important in the future of energy production. I became interested in finding a material that would be cheap enough and strong enough to allow fracturing of deep wells – generally wells deeper than about 7,500 feet.
“I worked to develop realistic test procedures and found that a ceramic material can be made into ‘proppant’ particles that do the job. This year about 3 billion pounds of ceramic pellets will be manufactured around the world and pumped into wells.
“It has been very interesting to see a technology develop from the laboratory into a new ceramic industry. The patent was, of course, assigned to Exxon, and it was one of the highest royalty-producing patents in oil and gas production. It has expired now.
“But the history of hydraulic fracturing technology has been a series of improvements, made by many engineers and scientists.”
In 2006, the Society of Petroleum Engineers (SPE) presented him with the “legend” honor. Cooke won the “Outstanding Inventor Award” of the Houston Intellectual Property Law Association for three inventions in the oil and gas industry. He also has made numerous SPE presentations and has written many technical papers published by the SPE.
Excerpts from Speaker Presentations
Peter Vig, Founder, Round Rock Capital –“Markets no longer see unconventional natural gas as generating attractive rates of return, certainly not relative to oil and liquids plays. Increasingly, the industry is pinning its hopes and allocating its capital to oil and liquids. The markets have certainly been open to funding this effort, and remain open. … The industry’s focus started to shift from gas to oil in 2003 with the development of the Bakken Shale in Montana with the play extended to North Dakota the next year. … The next major oil development was the Eagle Ford of South Texas, which consists of a dry gas phase, a high-liquid content, high BTU gas phase and a crude oil phase. … A study of 39 companies by BentekEnergy, the Denver consultant, showed the five best-performing stocks in the past year were all oil leveraged. CWE, Oasis, Conoco, Brigham and Pioneer Natural Resources showed gains from 78 to 110 percent. …
“Time is of the essence. In the early days of the Barnett and the Fayetteville, you still assembled fairly large blocks of prospective acreage at reasonable prices a year or more after these plays were in the public domain. Those days are long gone. The land rush today is truly amazing and a company generally is going to be required to commit its acreage dollars before it has all the answers or, in some cases, the industry lacks proof of concept. Let’s suppose you have missed out on the first wave of leasing. Just run the economics based on current acreage costs and see if the returns still justify the investment. Also, I strongly encourage you to reflect on the fact that per well reserves and productivity as well as returns generally improve with time in these unconventional plays.”
Norm Warpinski, Ph.D., Director of Technology, Pinnacle – “Complexity is difficult to distinguish in most oil-prone unconventional resources. ... There is little evidence of extensive “intrinsic” complexity in these reservoirs. ... Staging/clustering/stimulation factors apparently encourage complexity. ... Interplay between network complexity and fracture conductivity must be clearly understood.”
David P. Craig, Ph.D., Owner, Reservoir Development Consulting, LLC– “In unconventional reservoirs, multiple fracture pressure transient solutions can be used to estimate the number of producing fractures. ... Wellbore and fracture storage can be used to determine the fracture volume. ... Production data analysis can be used to estimate the number of producing fractures. ... Microseismic results are nearly instantaneous compared to production data analysis where monitoring over long time periods is required. ... Predicting the shape of the rate derivative curve requires a good estimate of permeability thickness, and a fracture-injection/falloff test at the toe of a horizontal is recommended during completion to estimate kh. ... While it may be possible to identify fracture complexity in pressure-transient or rate-transient data, it certainly isn’t simple.”
Bob Shelly, Director of Engineering Services and Competitive Analysis, StrataGen Engineering– “Data analysis and modeling can provide guidance about how to achieve the best return on investment for specific reservoir conditions. … Production and recovery from ultra-low perm require lots of fracture area. ... There is huge variation in reservoir and rock mechanical properties in shale. … Selection of proper frac staging methodology is not a black-and-white issue ... Many of the completion/frac parameters that affect oil production also affect water production in a similar way. … Frac treatment of long gross perforated intervals appears to reduce hydraulic frac effectiveness. … The data indicates that improved oil recovery and production rate will result with fracture spacing approaching 200 ft. … Economic analysis must be performed to determine appropriate completion/frac expenditures required to maximize return on investment.”