Securing energy independence has been an ambition of the United States for decades, and Marietta College’s Dr. Ahmed Algarhy has possibly had a hand in creating two innovative methods that may one day help achieve this goal.
Algarhy, along with two other inventors, recently received a U.S. patent for two procedures that increase the hydrocarbon recovery from shale reservoirs and sandstone reservoirs. Algarhy, Dr. Mohamed Soliman (University of Houston) and Dr. Lloyd Heinze (Texas Tech University) submitted the techniques for a patent four years.
“Hydrocarbon recovery from both conventional and unconventional reservoirs is very low,” says Algarhy, who joined Marietta’s Petroleum Engineering faculty in 2018. “The hydrocarbon recovery factor for conventional reservoirs is typically between 5% and 15% after primary recovery and between 35% and 45% after secondary recovery. The hydrocarbon recovery factor for organic shale reservoirs is typically between 5% and 10%, and around 70% of the hydraulic fractures created in such reservoirs do not produce.”
The first strategy, named “Complex Toe-to-Heel Flooding (CTTHF),” increases oil recovery from sandstone formations under specific reservoir conditions. Algarhy says CTTHF is an improvement upon conventional Toe-to-Heel Waterflooding and uses gravity segregation to increase the oil production rate and the total oil recovery.
The second completion strategy, named “Optimized Zipper Frac (OZF),” increases hydrocarbon recovery from organic shales. Algarhy says OZF is an improvement upon Zipper Frac (ZF), Alternate Fracturing (AF), and Modified Zipper Frac (MZF) because it uses ballooned fractures to create stress shadows that minimize stress anisotropy and thereby maximize near-wellbore complexity and production rate.
“A horizontal well completion method known as zipper fracturing has been rapidly adopted over the last 10 years by companies in the United States. Instead of drilling and hydraulically fracturing one well at a time, the zipper method involves drilling multiple wells from a pad site and then hydraulically fracturing a stage in one well, while getting ready for the next, as wireline and perforation operations take place in another,” says Algarhy, who is the director of PioPetro a non-profit educational project. “The multi-well completion method earns its name from the zipper-like configuration of the fracture stages from wells drilled with relatively tight spacing.”
A lot of companies in the US use the completion method on almost every new pad site they drill into, saving tens of millions of dollars per year while accelerating the development of their well inventories.
“But the big prize may be that zipper fractures are increasing initial production and estimated ultimate recovery rates when designed so that the fractures stimulate the most reservoir volume possible,” Algarhy says.
From 2003 to 2014, Algarhy worked in hydraulic fracturing design and implementation before he got the chance to complete his Ph.D. in petroleum engineering at Texas Tech.
“I wrote a proposal to Dr. Soliman, who is now in charge of the petroleum department at the University of Houston, and Lloyd Heinze, a professor at Texas Tech, and we agreed to develop these two new techniques as part of my Ph.D. work,” Algarhy says. “These two techniques help increase the oil and gas recovery and thus help secure more hydrocarbons for the U.S. and make our country more energy independent.”
An assistant professor, Algarhy teaches production and completion, geomechanics, and unconventional reservoir evaluation and development. Algarhy received the regional distinguished achievement award for petroleum engineering faculty for the eastern North America region in 2021.
Algharhy holds a Ph.D. and Master of Science in Petroleum Engineering from Texas Tech University. He also holds a Master of Science in Petroleum Engineering, Natural Gas Engineering postgraduate diploma, and Bachelor of Science in Mining Engineering from Cairo University in Egypt. He has more than 11 years of oil and gas industry experience with operation and service companies that focus on hydraulic fracturing, geomechanics, and unconventional reservoirs evaluation and development.