The permeability and fluid flow manipulation pillar has an overarching goal to develop the scientific basis and technologies to quantify, characterize and manipulate subsurface flow through an integration of physical alterations, physicochemical fluid/rock interaction processes, and novel stimulation methods implemented at the field scale.
Research in the Permeability Manipulation and Fluid Control Pillar is associated with four different topics, called elements, including:
- Manipulating Physicochemical Fluid-Rock Interactions
- Manipulating Flow Paths to Enhance/Restrict Fluid Flow
- Characterizing Fracture, Dynamics and Fluid Flow
- Novel Stimulation Technologies
Manipulating Physicochemical Fluid-Rock Interactions: The overall 10-year goal for this research element is to manipulate field scale fluid flow using improved understanding of coupled thermal, hydrological, mechanical, chemical and biological (THMCB) processes, and improve quantitative modeling to adaptively change fluid flux magnitude and flow pathways to meet subsurface engineering objectives.
A wide variety of coupled processes involving THMCB effects play out over a broad range of length and time scales during large-scale fluid injection or extraction in various subsurface applications. There are large uncertainties in predicting and modeling the interactions between the injectate, pore fluids (e.g., in nanopores), and minerals as well as organics in tight rocks. To remedy this shortcoming, research is needed to improve understanding of fracture-matrix fluid flow, fluid-organic-mineral, and fracture-tip interactions as a function of stress, temperature, and solution composition. A sustained research program combining enhanced characterization, high-resolution imaging, geomechanics, geochemistry, and coupled process experimentation and modeling is needed to address existing knowledge gaps. Reservoir geologic material from sites such as geothermal reservoirs, unconventional hydrocarbon reservoirs, potential nuclear waste repository formations, and caprock from prospective geologic carbon sequestration sites should be used. To meet the objectives of this pillar, systematic studies are required over a range of scales from pore to core to block to field, with tight integration between experiments, observations, and simulations.
Manipulating Flow Paths to Enhance/Restrict Fluid Flow: The overall 10-year goal of this element is to manipulate fluid fluxes and pathways using coupled THMCB processes at the fracture scale that affect the subsurface engineering objectives.
The primary means by which fluid flow can be manipulated is to control the fluid flow path. Some energy applications demand enhancements to fluid flow (e.g., hydrocarbon production), while others demand reducing or eliminating fluid flow (e.g., nuclear waste disposal, and geologic carbon sequestration). While hydraulic fracturing is widely used, and grouting of fast-flow paths is successful in some applications, there is a clear need for improved capabilities in this area as evidenced by rapid declines in production of gas from shale, and concerns about CO2 and CH4 leakage through fractures, faults and wells.
The ability to adaptively control fracturing in real time is needed to stimulate reservoirs. This demands a coupled injection-monitoring-modeling approach with a rapid response time. Improved understanding of fracture-matrix fluid flow in tight rocks is needed to enhance production. For reducing or eliminating flow paths, fluids or materials that change properties (e.g., solidify or become more viscous) as a function of natural or applied conditions are needed. This is useful for multi-step stimulations to create more pervasive fracture networks in the face of single, large fractures dominating flow. The plugging of leakage pathways through caprock and thermal short circuits are obvious applications for such technology. Another application is the delivery of fluids/materials to target zones for treatment or flow control.
Characterizing Fracture, Dynamics and Fluid Flow: The 10-year goal of this element is to provide methodologies to determine fracture/flow characteristics in the field and to identify and use potential signals to improve fracture/flow mapping.
In order to better control fracturing, fracture dynamics and fluid flow, it is critical to determine the effectiveness of control technologies. This requires improving the accuracy and sensitivity of current characterization technologies and the application of new technologies. Field deployment and demonstration of better fracture/flow characterization technologies is within the purview of the New Subsurface Signals pillar. Research and development (R&D) to improve understanding enabling prediction of the physicochemical controls on fractures and fluid flow performed within this pillar lends itself to both improve the effectiveness of current characterization technologies as well as to invent and develop new technologies. Efforts within this element will require significant interactions with those in the New Subsurface Signals pillar.
Novel Stimulation Technologies: The 10-year goal of this pillar is to develop and enhance stimulation methods for resource extraction.
While current stimulation methods have been successfully deployed to produce unconventional fossil and geothermal resources, there is a need to improve and develop environmentally sustainable novel stimulation methods. In some cases, novel stimulation approaches, including combinations of approaches, could make the difference between an economical and sustainable production well and one that would otherwise be abandoned. Depending on the relevant fracture initiation mechanisms, energetic approaches (e.g., high/low explosives or propellants) may provide advantages. Chemical approaches (e.g., acidization) coupled with mechanical stimulation could also have advantages. Laboratory and field experiments on new materials, propellants, and energetics are needed to develop the capability to deliver precise stimulation at precise locations with the desired rate of energy release. There is also the possibility of developing green fracturing fluids (less water or zero water) and thermal techniques, all of which need research and development.