Geomechanics Dominates in Unconventional Resource Development

As unconventional resources have grown in importance, geomechanics has emerged as a major discipline in the field.

This month’s Unconventional Resources Technology Conference in Houston July 23-25 provides a good example.

The inaugural conference in 2013 had a lone session in geomechanics.

This year, it is one of the largest programs, explained Gang Han, upstream petroleum engineering consultant for Aramco Services Co. He has been involved with URTeC since its inception in various roles: theme chair, session chair, keynote speaker and technical presenter.

“Nearly 140 geomechanical technical abstracts were submitted. Of those, 45 were selected for seven sessions.In addition, American Rock Mechanics Association will present a special geomechanics session for a second year in a row,” Han said.

“These sessions reflect the growing importance and multidisciplinary nature of geomechanics: from geoscience such as rock characterization, structural and tectonics presented by AAPG PSGD (Petroleum Structure and Geomechanics Division), pore pressure and in-situ stresses, to engineering such as fracture modeling, monitoring, diagnostics and performance,” he said.

“Essentially, geomechanics is the study of the behavior of soil and rocks. So, when you consider that the success of the unconventional revolution is based primarily on two technologies – horizontal drilling and hydraulic fracturing – you can understand why geomechanics is so important,” Han said.

Geomechanics threads through various disciplines in all stages of exploration and production, he noted.

Image Caption

Gang Han, upstream petroleum engineering consultant for Aramco Services Co.

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As unconventional resources have grown in importance, geomechanics has emerged as a major discipline in the field.

This month’s Unconventional Resources Technology Conference in Houston July 23-25 provides a good example.

The inaugural conference in 2013 had a lone session in geomechanics.

This year, it is one of the largest programs, explained Gang Han, upstream petroleum engineering consultant for Aramco Services Co. He has been involved with URTeC since its inception in various roles: theme chair, session chair, keynote speaker and technical presenter.

“Nearly 140 geomechanical technical abstracts were submitted. Of those, 45 were selected for seven sessions.In addition, American Rock Mechanics Association will present a special geomechanics session for a second year in a row,” Han said.

“These sessions reflect the growing importance and multidisciplinary nature of geomechanics: from geoscience such as rock characterization, structural and tectonics presented by AAPG PSGD (Petroleum Structure and Geomechanics Division), pore pressure and in-situ stresses, to engineering such as fracture modeling, monitoring, diagnostics and performance,” he said.

“Essentially, geomechanics is the study of the behavior of soil and rocks. So, when you consider that the success of the unconventional revolution is based primarily on two technologies – horizontal drilling and hydraulic fracturing – you can understand why geomechanics is so important,” Han said.

Geomechanics threads through various disciplines in all stages of exploration and production, he noted.

“Really, unconventional teams are all integrated now: geomechanics, geology, geophysics, drilling, completion and stimulation, production and reservoir engineering,” he said.

“It is applied in geology – where to find the ‘sweet spot.’ We need to understand the best rock, not just the oil,” he added.

“Successful rock drilling, keeping boreholes open and stimulating, such as hydraulic fracturing, rely on inputs from geomechanics,” Han also said.

The Bottom Line

“All this affects how much money we’re spending – it’s truly multidisciplinary,” said Keith Rappold, technology coordination chief with Aramco.

“Drilling and producing from unconventional, shale, carbonate or tight sandstone reservoirs is different.Unconventional rocks have their own unique characteristics and behaviors.As industry increases production of oil and gas from unconventional reservoirs, geomechanics experts are essential members of the development and operations teams.URTeC was created because there was a need for a conference that was an integrated event for unconventional resource teams,” said Han.

The shale revolution has spurred rapid advances in the evolution of geomechanics.

“In the early years or ‘gold rush’ stage, unconventional operators focused largely on obtaining land leases.Conventional or traditional geomechanical approaches and technologies, such as planning horizontal well trajectories or designing well stimulations, were applied.Geomechanics supported operations but it quickly became clear that shale drilling for oil and gas would be different – different from both a business model and a technical model,” Han said.

“Operators needed large numbers of wells to develop the land.Improving efficiency and reducing cost became the focus.Innovations came about with pad drilling, microseismic, zipper fracturing, and slick water to name a few.New technologies propelled geomechanics specialists into a key role in pad design, well planning, drilling, completion, stimulation, production, reservoir and environmental protection,” Han said.

The search for new approaches is a continuing effort, said Theo Mallinson, also a petroleum engineering consultant with Aramco.

“Two (URTeC) sessions look at applying gas injection in a relatively novel way,” he said.

“They are mostly lab papers – trying to discover underlying principles, but there are a couple of field tests. It’s a quite interesting area to keep an eye on,” Mallinson explained. “Gas injection has been used in the Permian for decades, but its application in unconventional areas involves many differences.”

“The question is whether it will be economical,” he added.

“With vast amount of data from thousands of wells, integration of multi-disciplines is the key to making good business decisions,” said Han.

“For instance, as refracturing becomes popular and more prevalent, understanding stress changes with production and depletion is critical for operators to select successful candidates,” he said.

Bridging Geologists and Engineers

“Geomechanics is linking geoscientists and petroleum engineers…Drilling events, cuttings, or parameters such as mechanical specific energy (MSE) can indicate rock characteristics and fracture productivity,” explained Han. “Stimulation efficiency is evaluated with microseismic events, fracture diagnostics and well testing. Down spacing of clusters, stages, or wells can benefit from geomechanical modeling to minimize fracture interference and avoid fracturing hits. The technical insights from geomechanics on these topics and others are contributing to the decision-making and defining the discipline as an essential part of operations teams.”

“At this stage, most engineers and scientists are either intimately involved, or familiar, with the field,” he added.

Han said the URTeC sessions should be worthwhile for any professionals at the conference.

“From conversations among the people in different areas, decision-makers are all wanting these inputs. It’s a good bridge,” said Susan V. Gonzalez, a spokesperson for Aramco.

The influence and importance of geomechanics is being recognized in geoscience and engineering education as well.

Most major universities have strong geomechanics programs, noted Han.

Introducing even younger students to science is also important, said Gonzalez.

For that reason, Aramco sponsors G-Camp, a geology camp designed for fifth- through 12th-grade STEM teachers, who take their newly acquired ideas and insights back to the classroom.

Han is a member of this year’s URTeC Technical Committee and chair for Theme 4:“Geomechanics in Unconventionals:From Mechanical Properties to Hydraulic Fracturing and Session Chair for Hydraulic Fracturing Simulation.” He is a board member of the American Rock Mechanics Association and the organizer for this year’s ARMA special session, “Principles, Simulation, and Practice.”

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