Summary of Worldwide Experience on Oilfield Utilisation for Commercial Geothermal Energy - Possibilities for Application In Indonesia

Abstract

Indonesia has a lot of mature oil fields that have high water-cut, where the produced water still has sufficient temperature that can be utilised for other purposes. One of the possible utilisation of the sufficiently high-temperature water from mature oilfield is for geothermal power generation through Organic Rankine Cycle binary power plant.

Worldwide, the idea of utilising oilfield wells for geothermal power generation has been discussed and studied in regards to reduce the operating cost of oil and gas production and to extend the life of ageing and near-depletion oilfields. Although commonly oil and gas reservoir is not as hot as conventional geothermal reservoir, but several studies concluded that some old oil wells in Texas and Wyoming are deep enough to reach the temperatures of 121 °C (Xin, Liang, Hu, & Li, 2012), and even some of the wells reach 210 °C.

Oil well produced-water needs to be treated and reinjected back to reservoir, and as the oilfields become more mature, the amount of produced water is increasing as the oil production decrease (Xin, Liang, Hu, & Li, 2012; Soldo & Alimonti, 2015) until to the point where the oilfield is depleted and is not producing oil anymore, only water. This water by- product is often hot enough to power some binary ORC (Organic Rankine Cycle) unit. In Texas alone, the generation potential of hot water from those old oil wells is estimated on around 47-75 billion MWh (Erdlac, Jr., et al., 2007). Other potential applications are for direct use such as agriculture product drying/cultivation, thermal bathing, etc.

This paper aims to summarise the worldwide experience of utilising the hot produced water from mature oilfields for various purposes such as electricity generation or for direct use application (e.g. heat exchanger, agricultural heating/drying, etc.). A literature survey was conducted from various studies and published research review the technology required for these aforementioned application. The potential for such an application in Indonesia is also discussed.