Repurposing Hydrocarbon Wells for Geothermal Use in the UK: The Onshore Fields with the Greatest Potential

Abstract

<jats:p>One potential opportunity for the decarbonisation of heat supply in the UK is the repurposing of onshore hydrocarbon wells for the production and/or storage of geothermal heat. This paper reports an investigation into the most favourable candidate sites for such repurposing, taking into consideration the available thermal energy outputs and technological options for heat use. A GIS mapping model was generated, combining public domain data on onshore wells and production data from onshore fields, provided by the UK Oil and Gas Authority, with available subsurface temperature data. This model has thus integrated information on location, depth, operational status, and bottom-hole temperature for onshore hydrocarbon wells with production rates from onshore fields in the UK. Of the 2242 onshore hydrocarbon wells thus reported, 560 have the potential to be repurposed, 292 of which are currently operating. Using aggregated water production data for all operating wells in each field, the fields with the greatest potential for geothermal repurposing are ranked. Two of these, the Wytch Farm and Wareham fields, are selected for more detailed analysis. Wytch Farm, the largest onshore oilfield in western Europe, produces water at ~65 °C that might yield a feasible thermal power output of ~90 MW. If an end use could be found where it might substitute for burning of natural gas, the value of this output would be ~£90,000 per day or ~£30 million per year. However, this field is located in a protected landscape where local development would be restricted by planning regulations. The Wareham field is not in a protected landscape, but the low temperature, ~44 °C, and low flow rate limit the scope of potential end uses. Nonetheless, these and the other highly ranked fields have potential heat outputs that are significant compared with other geothermal heat projects, thus offering the possibility of making useful contributions to the decarbonisation of UK energy use.</jats:p>

The heat recovery potential of ‘wastewater’: a national analysis of sewage effluent discharge temperatures

“…Comparatively, although it has been estimated that 36 000 000 TW h of geothermal heat storage capacity exists in the UK's 23 000 abandoned coal mines, only 40% of UK housing stock lies directly above these mines and heat would not travel well to the remaining 60%. 48 Similarly, projects which extract geothermal heat from hot subsurface rocks such as granites, 49 or from hydrocarbon fields and wells, 50,51 are also geographically restricted, and may also come with subsurface risks such as induced seismicity. 52,53 These potential limitations in comparison to wastewater heat recovery does not mean to say that these other technologies should not be pursued.…”

Geothermal Repurposing of Depleted Oil and Gas Wells in Italy

“…The first example of co-production or geothermal application of gas wells is the pilot plant in Pleasant Bayou field where, in 1980, a 1 MW hybrid cycle power plant was built to demonstrate the possibility of using existing wells to extract both gas and hot water and to produce electricity [5]. Since then, several studies on geothermal energy production from abandoned oil and gas fields have been conducted [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Conjugated Numerical Approach for Modelling DBHE in High Geothermal Gradient Environments

“…The potential repurposing of hydrocarbon wells has also been assessed through such designs [10,11]. It represents a significant amount of heat available without drilling costs [12]. Figure 1 shows the schematics of an actual DBHE experimented in Hawaii [13], for which water flows downward in the annular space and returns to the surface in an inner tubing.…”