Rehabilitation of Petroleum Wells as Borehole Heat Exchangers to Provide Heat for District Heating Networks in Small Towns or Villages: Case Study in Magallanes Basin, Chilean Patagonia

Abstract

As the Chilean National Oil Company (ENAP) has been exploiting oil and gas in Magallanes basin for more than six decades, 40% of the wells are no longer hydrocarbon producers. Therefore, the aim of this work is to assess the rehabilitation of oil and gas wells as Deep Borehole Heat Exchangers (DBHE) to supply the heating demand. Analytical calculation of heat transfer within the DBHE and with the surrounding rock are carried out to estimate the thermal energy and temperature levels output. For this work, the assessment is carried out for the 2,821 m depth Chulengo 1 well, which is next to village of Punta Delgada. Corrected Bottom Hole Temperature in well is 122 ˚C. The results indicate that rehabilitation of the Chulengo 1 well as a DBHE, can provide about ~82 kWth, which than supply the heating demand of 18 houses of 75 m^2. A district network is considered for heating the houses due to its wide range of long-lasting advantages. Regarding the assessment results and the significative percentage of no longer hydrocarbon producer wells, there are promising conditions for the development DBHE rehabilitating abandoned oil and gas wells with a low exploration risk and a high probability of success.