Constructing Deep Closed-Loop Geothermal Wells for Globally Scalable Energy Production by Leveraging Oil and Gas ERD and HPHT Well Construction Expertise

Abstract

Deep closed-loop geothermal systems (DCLGS) are introduced as an alternative to traditional enhanced geothermal systems (EGS) for green energy production that is globally scalable and dispatchable. Recent modeling work shows that DCLGS can generate an amount of power that is similar to EGS, while overcoming many of the downsides of EGS (such as induced seismicity, emissions to air, mineral scaling etc.). DCLGS wells can be constructed by leveraging and extending oil and gas extended reach drilling (ERD) and high-pressure high-temperature (HPHT) drilling expertise in particular. The objectives of this paper are two-fold. First, we demonstrate that DCLGS wells can generate power / electricity on a scale that is comparable to EGS, i.e. on the order of 40-55 MW per well. To this extent, we have developed a coupled hydraulic-thermal model, validated using oil and gas well cases, that can simulate various DCLGS well configurations. Secondly, we highlight the technology gaps and needs that still exist for economically drilling DCLGS wells, showing that it is possible to extend oil and gas technology, expertise and experience in ERD and HPHT drilling to construct complex DCLGS wells. Our coupled hydraulic-thermal sensitivity analyses show that there are key well drilling and design parameters that will ultimately affect DCLGS operating efficiency, including strategic deployment of managed pressure drilling / operation (MPD/MPO) technology, the use of vacuum-insulated tubing (VIT), and the selection of the completion in the high-temperature rock zones. Results show that optimum design and execution can boost initial geothermal power generation to 50 MW and beyond. In addition, historical ERD and HPHT well experience is reviewed to establish the current state-of-the-art in complex well construction and highlight what specific technology developments require attention and investment to make DCLGS a reality in the near-future (with a time horizon of ∼10 years). A main conclusion is that DCLGS is a realistic and viable alternative to EGS, with effective mitigation of many of the (potentially show-stopping) downsides of EGS. Oil and gas companies are currently highly interested in green, sustainable energy to meet their environmental goals. DCLGS well construction allows them to actively develop a sustainable energy field in which they already have extensive domain expertise. DCLGS offers oil and gas companies a new direction for profitable business development while meeting environmental goals, and at the same time enables workforce retention, retraining and re-deployment using the highly transferable skills of oil and gas workers.

Russian fuel and energy complex technology policy at the moment of energy transition

“…For example, one of the promising technologies is deep closed-loop geothermal systems, which require wells with a vertical depth of 5 to 10 km with bottomhole temperatures of 250 °C to 350 °C and extremely high pressures. One well in this case can produce up to 55 MW almost anywhere in Russia and the world [13].…”

CLIMATE CHANGE MITIGATION STRATEGIES IN THE OIL & GAS SECTOR: A REVIEW OF PRACTICES AND IMPACT

“…By minimizing the number of wells needed, horizontal drilling reduces surface disturbance and habitat fragmentation, thereby mitigating the impact on ecosystems (Lyons, et. al., 2020, Sahu, Kumar & Sangwai, 2020, Van Oort, et. al., 2021.…”

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“…In the operational phase of the oil and gas projects, the most critical aspect is experienced because it helps in lining the resources appropriately and further streamlining the process, which does not harm every stakeholder (Oort et al 2021 ). Significant emphasis is made from the operational perspective in research that it is relevant to safety and, ultimately, without protection, there is no sustainability.…”

“…However, the accepted reality from the existing research is that the demolition methods need significant improvements to become more relevant with the technology that can bring sustainability to the construction of oil and gas projects. There are implications from the current research need for improvement in the method adopted for planning the demolition work in oil and gas projects (Oort et al 2021 ). Mobility is one of the chief factors in demolition work because it can make the resource scheduling process more efficient and reduce time, which is one of the critical factors in any construction project (Table 2 ).…”