Jolante Wieke Van Wijk

To achieve net-zero emissions by 2050, we need economic means of sequestering carbon dioxide (CO ) and reducing greenhouse gas emissions (GHG). We analyze the sequestration potential of the Intermountain West (I-West) region, US, as a primary energy transition hub through analysis of wellbore retrofit potential and emission reduction in both fugitive gas abatement and flare gas. We selected the I-West region due to its abundant energy sources and oil and gas production legacy. Preliminary analysis hints that well retrofits can breathe new life into a well at a fraction of the cost of a new drill. With millions of potential candidates in the US, even a modest fraction (1% or less) suitable for retrofit could accelerate the shift to large-scale CO sequestration. Fugitive gas, the unintentional release of wellbore gases such as methane, is a significant emissions source. Through conservative analysis, it is estimated that wellhead leakage alone may account for 5 million tonnes of carbon dioxide equivalent (CO e) emissions. We conclude by assessing the CO emissions from flaring, which is the burning of associated gas during well operations, conservative analysis indicates flaring contributes another 2 million tonnes of CO emissions to the region. We find that with targeted retrofit and better controls on emissions sources, the I-West region can make a significant impact in the nation's push to become net-zero. This study outlines economic feasibility and actionable items to achieve the critical reductions in emissions and increases in sequestration necessary to attain net zero.

The produced water (PW) volume in the Intermountain-West (I-WEST) region is about 600 million m3 in 2021. More than one-third of the PW is injected for disposal, which can be a waste of water, considering the water scarcity in the I-WEST region. In this work, we analyzed the potential for the reuse of PW in the I-WEST region. The PW composition and volume in different basins in the I-WEST region were analyzed. The regulations for drinking water, domestic use, irrigation, livestock watering, aquatic, surface water discharge, groundwater discharge, hydraulic fracture, and hydrogen (H2) production were summarized. We identified the appropriate treatments depending on the PW composition and water standards. We also analyzed each PW treatment's water recovery, energy demand, and cost. We selected the samples of PW from the Raton Basin, San Juan Basin, and Permian Basin to assess the potential reuse of PW in the I-WEST region. The comparison between PW composition and water standards shows that the regulations are not designed for the reuse of PW because the constituents in water regulations do not match the constituents in PW. The low-salinity PW can be treated for agricultural use with relatively low cost and high water recovery, while the high-salinity PW is more suitable for hydraulic fracturing. The treatment cost (including operation, maintenance, energy, labor, and disposal cost) ranges from $0.11/bbl to $1.01/bbl, depending on the PW composition and targeted water standards. The reuse of PW for H2 production is a promising usage purpose. Due to the high demand for fresh water in H2 production, the reuse of PW can alleviate the stress of water scarcity in the I-WEST region. This work provides guidance for the reuse of PW in the I-WEST region.

Interplay between marginal and intraplate late Paleozoic tectonics in southeastern Laurentia is a subject of debate. In southern Laurentia, intraplate deformation has been attributed to combinations of compressive forces from orogenic belts in the west, southwest, and southeast. While left‐lateral transpression is generally an accepted mechanism for formation of uplifts in the Southern Oklahoma Aulacogen (SOA), to date no studies have explained the driving mechanisms of these kinematics. Here, we analyze the Southern Oklahoma Transpressional System (SOTS), a ∼500 km long ∼50 km wide fault zone that extends from the southeastern Laurentian margin into the plate interior along Cambrian lithospheric weaknesses inherited from the SOA. We use a compilation of published studies to present detailed, time‐integrated sedimentary thickness maps of SOTS‐related basins. We combine these maps with a new interpretation of three 2D seismic reflection lines to constrain timing and kinematics of all major late Paleozoic SOTS fault zones. We show that the SOTS kinematics evolved from contraction to left‐lateral strike‐slip during Mississippian‐Pennsylvanian time. Tectonic activity and fault kinematics in the SOTS are explained by a model in which a remnant ocean basin closed diachronously from northeast to southwest along the Southern Appalachian and Ouachita‐Marathon orogens. Left‐lateral transpression during diachronous closure of the Rheic oceanic basin along the Ouachita‐Marathon margin is related to rotation of the stress field due to changes in slab‐pull and eastward drift of Laurentia toward Gondwana. We speculate that the SOTS acted in part as a STEP (subduction‐transfer edge propagator) fault that followed the pre‐existing SOA. Key Points Slab‐driven tectonics along the SE Laurentian margin Southern Oklahoma Transpression System links marginal and intraplate deformation late Paleozoic kinematics change from oblique convergence to left‐lateral strike‐slip in the Southern Oklahoma Transpression System