Smart-GeoWells: Smart technologies for optimal design, drilling, completion and management of geothermal wells

Lead Research Organisation: Imperial College London
Department Name: Earth Science and Engineering

Abstract

A novel product will be developed for designing, drilling, completing and managing well systems that incorporate many laterals with increased reservoir contact for geothermal industry. A hybrid drilling approach, based on conventional and jetting (water and supercritical-CO2) technologies, will be employed along with advanced numerical models to help optimise the deployment and management of the well system. The product targets the fast-growing geothermal industry, and can be readily re-applied to oil/gas production, with a particular focus on intermediate-deep geothermal resources. Objectives of this work include: (1) application of advanced well drilling and completion technologies for more efficient well system construction; (2) evaluation of new-generation numerical models for solving fluid flow and heat transfer problems in complex well-reservoir systems, (3) optimisation of well design and management for cost-effective production, and (4) deployment of the product to geothermal reservoirs for field trials. The novelty of this project comes from the unique combination of new drilling and completion technologies with novel computational methodologies for well management and production.

China's current energy demands require innovative, cost-effective and environment-friendly solutions. We are proposing an innovative multi-lateral well system Smart-GeoWells to help meet these challenges. This will be used to develop cleaner, more affordable, localised (building, village, town, city) heating/hot water and electricity, harnessing almost limitless, sustainable and secure geothermal energy. In order to develop the new multi-lateral wells (with potentially hundreds of laterals), the proposed team (each member a world-leader in their fields) will apply their specialised knowledge in testing and exploiting the new well engineering solutions, hybrid drilling technologies, advanced numerical modelling and optimal well design and management methods. For the UK and China teams, this will be the first stepping stone towards long-term collaboration, aiming at optimal exploitation of geothermal resources and if successful will have a massive impact on the energy sector. However, the scope of the work is also immense and thus our initial product (that we aim to develop rapidly) will be focussed on geothermal hot water production, although the developed technology can serve as a longer term product for geothermal electricity generation as well as O&G production. The new multi-lateral drilling concepts of XLTL (project partner) together with the novel techniques in modelling multiphase fluid flows and heat transfer through these large number of laterals (similar to the fishbone structure), will lead to economic and efficient ways of drilling financially-competitive multi-lateral wells through: a) enhanced contact and connectivity with geothermal regions; b) minimisation of environmental damage i.e. pollution of groundwater sources/surrounding countryside and c) optimal control/management of the production wells. During the project, Sinopec will provide geothermal sites, test equipment and specialised engineers/technicans for field trials (the company's funding contribution amounts to 5 million RMB) with which the advanced drilling techniques will be examined and the prediction software will be validated. The developed Smart-GeoWells platform will be made available to the interested local and other companies/businesses, as well as public services, and will also benefit them through enhanced knowledge and technology transfer. The longer-term implications on the welfare of the local and other communities are immense, both directly through reduced pollution (water and air) and climate change impacts and, indirectly, through economic impacts.

Planned Impact

Smart-GeoWells is a technology which will lead to the development of an economical, fast and environmentally sustainable geothermal energy production using new wellsn systems. It can lead to well productivity increases of more than 3 times and enable the wells to be produced quicker than conventional methods. This project will substantially reduce the commercial and technical risks in future development stages and will ultimately enable China and the UK to become a world technology leaders in geothermal energy. Smart-GeoWells embodies a novel concept which will allow numerous laterals to be drilled in various spread patterns, from a horizontal or a vertical well, without the need to use acid-loaded fracking fluids and without the use of hydraulic fracturing.
1. Environmental: (a) There is a potential for geothermal energy to substantially reduce fossil fuel burning as well as obtain readily available, renewable energy with sustained and predictable power output (not reliant on weather conditions) - essential for China to meet its growing industrial and public needs. The reduction in fissile fuel burning will: i) reduce CO2 emissions - hence, effect on climate change ii) reduced SO2-contribution when open-loop systems are used, compared to equivalent coal-based electricity plants; (iii) no pollutants relased when closed-loop systems are used; thus, an overall reduction in air pollution, hence enabling healthier atmospheric environments for people - particularly crucial for China due to its size and hence reduction of spreading of air pollutants worldwide. (b) Smaller area of land usage for injection and production geothermal wells; avoidance of land subsidence by re-injection of wastewater. Thus, the everyday person in China will benefit from cleaner air, reduced climate change effects (natural hazards like flooding) from reduced CO2 emissions, cleaner water (reduced fracking).
2. Economics and Poverty: (a) Most developed nations have active policies of increasing their renewable energy supply including geothermal energy as long as political, technical and economic obstacles can be overcome. Our technology will be the first to achieve all of the above obstacles. Extensive patent searches have shown only one other emerging technique for creating multiple laterals, developed by a Norwegian company: Fishbones ASA - which, however, has fundamental issues:(i)a likelihood of gradual decline in flow (fluid and heat); (ii) future interventions more challenging as the turbines used in the drilling system remain in the motherbore; (iii) limitation on the drilled hole length. Our proposed methodology is free from these issues; (b) Local communities - particularly in remote villages and towns - will directly benefit from the increased economic activities in their area, through employment in the newly-developed geothermal plants, as well as reduced heating and electricity costs - particularly in North China;the resulting activity around geothermal plants will promote increasing wealth in such areas and reduction in poverty; (c) through education (research and technology) and improved environmental policies; (d) through reduction in financial risk of geothermal energy and sustained predictable renewable energy not provided by wind or solar energy;
3.Improved Health: The improved economy and reduction will poverty will have a direct effect on the health of the communities served by geothermal energy - as the quality of life will be massively improved through the provision of cleaner and cheaper electricity and heating, and through the reduction of pollution.
A better understanding and management of geothermal wells will also:(i) Improve exploitation of geothermal resources which will allow for decreased oil imports and lower air pollution, lower energy costs and ease the transition to post fossil fuel transport. (ii) The new well technology may also be used for CO2 re injection and sequestration.

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