Geothermal Repurposing of Depleted Oil and Gas Wells in Italy

Abstract

The decarbonisation of the energy sector is probably one of the main worldwide challenges of the future. Global changes urge a radical transformation and improvement of the energy-producing systems to meet the decarbonisation targets and a reduction of greenhouse gas emissions. The hydrocarbon industry also contributes to this transition path. In a mature stage of oil and gas fields, the production of hydrocarbons is associated with formation waters. The volume of produced water increases with the maturity of the assets and the geothermal repurposing of depleted oil and gas wells could be an alternative to the mining closure. In the described transition scenario, the geothermal energy seems very promising because of its wide range of applications depending on the temperature of extracted fluids. This flexibility enables us to propose projects inspired by a circular economic vision considering the integration in the territory and social acceptance issues. In Italy, since 1985, 7246 wells have been drilled for hydrocarbon, of which 898 are located onshore with a productive or potentially productive operational status. This paper presents a preliminary investigation of oil and gas fields located onshore in Italian territory based on the available information on temperature distribution at different depths. Then, taking into account the local energy demand, existing infrastructure, and land use of the territory, a conversion strategy for the producing wells is proposed for three case studies.

A Review of North American Prospects for Power and Hot-Water Generation with Thermal Energy

“…However, these projects require a comprehensive review from engineering and economic perspectives. Repurposing hydrocarbon wells for geothermal use during an oilfield's late life has been explored in the UK [11] and Italian [12] contexts. While reusing abandoned wells [2,[13][14][15][16][17][18][19][20][21][22][23] appears attractive from a capital investment standpoint, challenges exist, including difficulties in controlling desired well depth and geothermal gradient in abandoned wells [10], and concerns related to mechanical integrity due to the well's age.…”

Understanding Thermal-Energy Extraction Prospects in Wellbore Fluid Circulation

“…Repurposing hydrocarbon wells for geothermal use when an oilfield is in late life has been recently studied in both the U.K. [11] and Italian [12] settings. Earlier, a plethora of studies [3,[13][14][15][16][17][18][19][20][21][22][23][24][25] promoted reusing abandoned wells.…”

Closed-Loop Systems for Geothermal Energy Exploitation from Hydrocarbon Wells: An Italian Case Study

“…Over time, a variety of hydrocarbon reservoirs has been identified, and Italian sedimentary basins have been explored for both oil and gas extraction purposes. Since 1985, 7246 wells have been drilled for hydrocarbon extraction in Italy, 898 of which are located onshore with varying operational statuses [4]. Additionally, geological and geophysical exploration campaigns into the deepest regions of such geological contexts have ascertained the coexistence of hydrocarbons and low-temperature to medium-temperature geothermal energy resources [5,6].…”