Unconventional resource development has a remarkable history, combining breakthroughs and advances in both technology and geoscience.
The pace of progress might have slowed in recent years, but that history is still being written.
As a brief timeline, the 1990s were years of experimentation in unconventionals, leading into a decade when the oil and gas industry learned how to apply the coupled techniques of horizontal drilling and hydraulic fracturing.
Over the ensuing 10 years, output from unconventional resources soared to account for more than 70 percent of dry gas production and 60 percent of oil production in the United States, according to the U.S. Energy Information Agency.
“My belief is that we do have about 13 years of experience in developing shale gas and shale oil/tight oil, and we have definitely demonstrated that we can effectively drill, complete, stimulate and produce from these reservoirs,” said Tom Blasingame.
“This capability cannot be overstated – we have come a long way in a very short time,” he noted.
Blasingame is 2021 president of the Society of Petroleum Engineers and Robert L. Whiting professor of petroleum engineering at Texas A&M University in College Station, Texas.
A Singular Vision
He said the industry downturn and subsequent 2020 pandemic “really took the momentum out of the technology side of unconventionals.”
“Interestingly, recent conversations and comments have ranged from, ‘We know the plays, we don’t need geoscience anymore,’ to ‘Technology and data are too expensive and we haven’t seen the benefit,’ as well as ‘We have our well pattern, no more field trials/experiments,’” Blasingame observed.
“Obviously, I disagree with these points,” he said.
Today, operators benefit from practices that have moved far along the unconventionals learning curve, Blasingame noted.
“Personally, I believe that we have achieved all but a few technical needs — the parent-child (well) relationship being the most elusive. The ability to understand where fluids are being produced from and how to achieve optimal primary recovery are also long-term challenges,” he said.
Blasingame will discuss the “Future of Unconventionals – Geoscience and Engineering Aspects” at a topical luncheon during the Unconventional Resources Technology Conference, July 26-28 in Houston.
His presentation at URTeC will draw on the work of a small study group as well as a large-scale, “crowd-source” effort.
“This has been sitting in the back of my mind for a couple of years. I thought it was time to create an initiative to try to capture prior learning and to enable forward-thinking on unconventionals,” Blasingame said.
“Realistically, my vision on this study group is too ambitious. There are too many people working on too many aspects of unconventionals to make a single initiative successful,” he added.
He said his goal for the URTeC luncheon presentation is “pretty simple. I would like to give a vision of what I believe study groups on unconventionals should be pursuing – people, technology, data, etc. Realistically, my goal is to see if there is traction within the unconventionals community for such an initiative.”
A ‘Complete Change of Capability’
Blasingame said he had engaged with a colleague who primarily works on the well completion-and-stimulation side of unconventionals, and it became obvious that it would take multiple initiatives to capture the knowledge developed to date.
“We must be candid that we did not develop unconventionals in a universally economic fashion, but again, technology development in unconventionals is the equivalent of the jet engine, compared to conventional reservoirs being the propellor-driven plane. It is a complete change of capability,” he said.
“Thinking in terms of ‘What if I were a new operator in a new or existing play?’ can be helpful, ‘What do I need to achieve optimal performance and recovery in both a technical and an economic sense?’” Blasingame said.
He noted that many people in the U.S. oil and gas industry have focused the past 13 years of their lives on unconventional resources.
“I believe it is time for a bit of soul-searching on the technical and economic aspects of unconventional reservoirs, not to return to a blank page, but to carefully and consistently consider what has worked, what hasn’t and why,” he said.
While “trillions of barrels of oil and thousands of Tcf of natural gas are technically recoverable from unconventional reservoirs, the question remains as to how to move from technically recoverable to economically recoverable. Frankly, I believe this will occur from a commitment to technology, and field experiments and demonstrations,” he commented.
The hundreds of billions of dollars spent on unconventionals to date has forever changed the industry’s expectations of deliverability, and on how quickly the industry can develop and deploy technology, Blasingame noted.
He said unconventional reservoir development has led to numerous, rapid advancements in improved technologies for reservoir engineering/modelling, petrophysics, geo-descriptions, geomodelling, production facilities and well stimulation.
“These advancements are nothing short of revolutionary and should not be lost or squandered. We need to ensure that as an industry, for both unconventional and conventional operators, we maintain our momentum in unconventional reservoir technologies,” he said.
According to Blasingame, the benefits have included better logistics on services; development of water-management best practices; a renaissance in geomechanics, petrophysics and geochemistry; the development, deployment and demonstration of extremely large-scale well stimulation; significant evolution in reservoir modelling; and rapid development of data-analytics capabilities for operations, planning and deployment.
Blasingame said key questions remaining to be addressed include:
- What are the enabling technologies for enhanced oil recovery in unconventionals?
- Can we and do we understand key factors and limitations in hydraulic fracturing?
- Do we really understand geology, geophysics and petrophysics in unconventional reservoirs?
- Where does geomechanics affect hydraulic fracturing? Reservoir performance? Reservoir recovery?
- Where, when and how do data analytics provide insight into unconventionals?
- Did we miss something in modelling (scaling: nano-, micro-, macro-scales, fractures, geomechanics, reservoir fluids)?
He identified three immediate challenges for unconventional resource development:
• Parent-child well relationships: Well performance interference and recovery reduction
“I had been thinking that we should just back-off to a minimum well spacing of 1,000 feet, but this is probably neither desirable, nor practical. Understanding the ‘connected’ fracture system is critical as interference is due to the hydraulic and natural fractures,” he said.
• Hydraulic fracture characterization: Understanding factors controlling the vertical and lateral growth of the fractures, as well as the directional aspects
“This is well outside of my expertise as a reservoir engineer, but I can help to provide diagnostic guidance based on measured pressure interference,” Blasingame said. “I know that fracture monitoring and characterization activities are very expensive, but relative to the potential value of understanding what is interfering and where not to drill/complete, I think this cost is necessary.”
• Completion optimization: Treatment size, cluster spacing, proppant type and quantity
“I think we all realize that completion optimization practices vary significantly from play-to-play, but this ‘recipe’ requires constant attention to optimize well performance and recovery with cost and complexity of stimulation treatments,” he said.
What keeps Blasingame up at night thinking about unconventional reservoir development?
“Economics must be at the core of everything we do, but I believe we are still at the proof-of-concept, in many ways. We know that unconventionals are technically producible and recoverable, but only at scale are these economic,” he observed.
“It took a long time for me to realize, and admit, that geology was really the key to any given play. I assumed that we could use technology and brute force to achieve productivity. In short, geology matters – a lot,” he said.
In addition, “technology must be fit-for-purpose,” Blasingame noted.
“There is no ‘one-size-fits-all’ technology, nor should there be, but getting people who are accustomed to conventional reservoir processes and technologies to adapt to unconventional thinking is where the challenge lies,” he said.