AREAS OF ONSHORE OIL & GAS RESEARCH
The Department of Energy’s (DOE) Office of Fossil Energy’s Onshore Oil and Gas Research and Development (R&D) Program, which primarily focuses on three program elements - basin-specific unconventional oil and gas, produced water, and data analytics - aims to increase ultimate recovery and operational efficiency of U.S. onshore oil and gas resources.
Onshore Basin-Specific Research
The DOE’s onshore research portfolio examines questions in scientific detail at a level that is generally not possible or cost effective for industry to do. Current R&D activities explore reservoir and shale behavior from “pore to core to reservoir scale” that is from nano-scale to the macro-scale in order to increase ultimate oil and gas recovery and operational efficiency, while in an environmentally sustainable way.
The conventional reservoir is a porous rock formation that contains oil and gas that have migrated from a source rock (unconventional reservoir). The oil and gas pathways are better connected and can be produced either/or by vertical/slanted wells. The productivity is better than that of unconventional. However, much of the oil and gas is left behind the bore hole due to basin specific reservoir properties, ineffective well completion design, and fluid-gas interaction in the reservoir.
In contrast to conventional reservoir, the unconventional reservoir contains oil and gas that were formed within the rock and never migrated. The challenges to unconventional resource development include geological and engineering variables that affect production from unconventional reservoirs.
These reservoirs’ properties are geologically complex. The rock types such as shale, tight sandstone, and carbonates exhibit very low permeability (near absence of connected pores for oil and gas to flow to the drilled well bore). The rock formations are more or less tabular forms.
The reservoirs need to be hydraulically fractured to create oil and gas flow-pathways. The well bores are designed to be drilled as horizontals so that the well path covers maximum reservoir thickness to effectively fracture the reservoir hydraulically in order to enable maximum possible oil and gas production. Horizontal wells help decrease well density in the field.
The DOE’s research aims to enhance oil and gas ultimate recovery from both existing and new wells in mature and emerging basins across our country.
The DOE is developing a suite of “field laboratory” test sites to achieve this goal. The DOE currently has about 17 field lab projects across the U.S. which carry out collaborative research with industry, academia, and DOE national labs to improve the recovery of unconventional and conventional oil and gas resources using a basin-specific approach.
Each oil and natural gas basin in the U.S. has unique reservoir properties and requires specific strategies for oil and gas production. The DOE’s basin specific strategy uses a three-prong research approach - field laboratories, fundamental shale research, and a data driven approach (employing high performance computing/artificial intelligence and machine learning/big data technologies) to decipher reservoir properties from pore to core to reservoir scale- with the goal of achieving ultimate oil and gas recovery.
The DOE’s Field Laboratories will identify and accelerate the development of economically-viable technologies to more effectively locate, characterize, and enhance ultimate oil and natural gas recovery and operational efficiency in an environmentally sustainable manner.
Fundamental Shale Research is conducted in collaboration with DOE national labs to investigate the behavior of shale formation at micro- and nano-scale in an attempt to improve subsurface science knowledge.
Oil and gas are extracted by creating pressure gradient within the reservoir that cause the oil and/or gas to flow through interconnected pores to production wells. Oil flows through the production wells to the surface because the pressure at the base of the well exceeds that exerted by the hydrostatic head (weight due to gravity) of the column of oil in the well. The oil production rate over time tends to decrease as the reservoir pressure decreases.
The chemical and mechanical properties of reservoir rocks significantly affect the oil and gas flow from the reservoir to the well resulting in low productivity. Understanding how rocks from different basins behave differently under subsurface reservoir conditions is important to improve ultimate recovery.
The DOE’s fundamental shale research approach identifies and addresses the different basin specific barriers to enhance ultimate oil and gas recovery while helping removing various barriers such as low recovery, low permeability (lack of connected pores), flow assurance and operational efficiency:
- An average 60 to 70 percent of oil is left behind in the producing reservoir. To address the low recovery, the pressure gradients are monitored and maintained by injecting another fluid (water, acid), gas (CO2, produced gas) and/or polymer into the reservoir through injection wells. The injected fluid/gas displaces the oil out of the reservoir and occupies the pore space that the oil originally occupied. For gas fields, the pressure at the production well is decompressed so that gas in the reservoir expands as the pressure drops and then flows to the production well.
- Reservoir rocks’ properties such as matrix chemistry and cemented material influence pore connectivity. Basin specific reservoir low permeability stems from combined factors such as rock mechanical property (stress and strain relationship), rock rigidity to fracturing and fracture propagation, open aperture, and distribution geometry.
The DOE’s National Laboratories’ research aims to identify and mitigate these production barriers by investigating mechanical/geochemical/hydrologic response to stimulation and production of shale resources through multi-scale laboratory experiments, numerical modeling of shale deformation, and fluid transport to predict fluid transport in pore-to-reservoir scales.
Data Driven Approaches Employing Artificial Intelligence (AI)/Machine Learning (ML)/Big Data combined with Numerical/Statistical modeling efforts aim to draw meaningful insights from the huge data generated from our research which can inform oil and gas industry decision-making in real-time.
The DOE’s National Laboratories utilize these advanced computational and world-class science capabilities to integrate physics-informed statistical models, inverse models (such as neural network), NLP (Natural Language Processing), Big Data Analytics, and other rapidly evolving AI/ML technologies to help draw meaningful insights from subsurface reservoir data for real-time-rapid visualization and prediction in order to enable effective decision-making. Our model will help us visualize and inform near-term and long-term strategies that can be adjusted over the life of the reservoir to increase total oil and gas production.
Projects conducted under this effort can be found at the DOE’s National Energy Technology Laboratory (NETL) and Fossil Energy Oil and Gas. The FE News sign up invite link will deliver regular updates to your email inbox.
Enhanced Oil Recovery for Conventional and Unconventional Reservoirs
Oil production from conventional reservoirs has been going on for decades. However, even under the best of circumstances primary, secondary, and tertiary (enhanced) techniques can ultimately lead to recovery of 30 to 60 percent of the original oil in place, leaving behind large volumes of oil in a conventional reservoir. The recovery factor for unconventional oil recovery is even less, with only about 5 percent, because of the relatively low permeability of the unconventional oil reservoir rocks. Consequently, oil and gas trapped in unconventional reservoirs (such as oil in fractured shale source rocks, kerogen in oil shale, or bitumen in tar sands) constitutes a vast potential domestic supply of energy.
The application of Enhanced Oil Recovery (EOR) methods to overcome the physical forces holding oil and gas underground can turn these accumulations into domestic oil reserves capable of supporting economic growth for decades to come. CO2 injection for miscible flooding, already the most common EOR method, holds even greater promise if it can be more widely applied to mature oil fields across the country rather than only in fields close to natural sources of CO2. The re-injection of natural gas associated with oil production is also being investigated as a mechanism for EOR; this not only enables incremental recovery, but also reduces the need for flaring of natural gas during production.
Accelerated development of EOR technologies will allow the U.S. to take advantage of new opportunities to: (1) maintain our growing energy independence by augmenting new sources of tight oil production; (2) economically utilize captured CO2 while reducing emissions; (3) optimize the use of associated gas; and (4) maximize the lifetime utility of existing infrastructure and wells in mature conventional fields.
Building on the DOE’s history of supporting the development of advanced EOR technologies, the current research program covers conventional and unconventional reservoirs.
At present, the DOE is funding field-based research focused on:
- Next generation CO2-EOR technologies that can increase recovery from existing producing conventional and unconventional reservoirs and accelerate application of the process to other mature oil fields around the country;
- Ways to improve the performance and lower the cost of chemical floods, as well as ways to accelerate their application by independent producers, which are the most likely operators of mature U.S. oil fields; and
- Methods for enhancing recovery of oil and gas locked in unconventional reservoir rocks like in the Bakken, Permian, and the Eagle Ford shale formations or that have characteristics that make their production difficult (such as heavy oil in Arctic reservoirs).
Projects being conducted under this effort can be found at NETL.
Produced Water Research
Produced water is the water that comes to the surface as a byproduct of oil and gas exploration and production. It includes native formation water and fluids that are brought to the surface during normal production operations including stimulation processes such as hydraulic fracturing.
Over the past decade, increased unconventional oil and gas development in the U.S. has led to a dramatic increase in the volumes of produced water requiring disposal, particularly in Texas, Oklahoma, and Appalachia. Each barrel of produced water that is disposed of via deep well injection rather than being re-used requires the supply of an additional barrel of fresh water as a replacement. Some of the challenges of disposing produced water via deep well injection include the non-availability of a deep well site near the production site and the potential of induced seismicity when large volumes of produced water are injected over a long period of time.
To address these issues, the DOE is currently conducting research efforts that could help in accelerating the development and application of low-cost treatment technologies that can simultaneously reduce the volume of water requiring disposal and provide a new source of fit-for-purpose water. This R&D effort supports the Water Security Grand Challenge, a White House-initiated, DOE-led framework to advance transformational technology and innovation to meet the global need for safe, secure, and affordable water. One of the goals of the Grand Challenge is to transform produced water from a waste to a resource. Information on the projects being conducted under this effort can be found at NETL.
HOW THE DOE DOES BUSINESS
The DOE’s Office of Fossil Energy’s Onshore Oil & Gas Research Program sponsors research activities in two ways.
- Cost-Shared Research
The DOE’s Office of Fossil Energy partners with a wide range of entities including academia, private sector companies/institutes, and foreign governments to gain a full range of expertise and resources for targeted research and development areas. Information on how to participate in a DOE competitive solicitation can be found at https://netl.doe.gov/business/solicitations.
- National Laboratory Research
The DOE’s National Laboratories and Technology Centers are a system of facilities and laboratories overseen by the DOE for the purpose of advancing science and technology to fulfill the DOE’s mission. Sixteen of the seventeen DOE national laboratories are federally funded research and development centers administered, managed, operated, and staffed by private-sector organizations under management and operating (M&O) contracts with the DOE. Only one of the DOE’s seventeen national labs, NETL, is government-owned and operated. It is sponsored by the DOE’s Office of Fossil Energy and is in a unique position to provide technology solutions and strategic partnerships dedicated to fossil energy research and development, including Office of Fossil Energy Onshore Oil & Gas Research.