Geothermal Conceptual and Numerical Modelling of a Gas-Condensate Field in the Eastern Llanos Basin, Colombia
Author: Andrés Felipe Laverde Martínez
Year: 2022
Supervisors: Dr. Juliet Ann Newson, Dr. Camilo Franco Ariza, Chelsea Cervantes
Abstract:
This project presents three-dimensional conceptual and numerical flow models of a gascondensate field in the foothills region of the Eastern Llanos Basin in Colombia. The Eastern Llanos Basin has been the subject of diverse studies for hydrocarbon exploitation. Over the past decade, this region has been assessed for its geothermal potential in currently exploited oil & gas fields. A gas-condensate field located in the foothills of the basin represents a promising opportunity to produce geothermal energy. The conceptual and numerical models integrate geological, geophysical, geochemical and well data to enhance the understanding of the geothermal system in a sedimentary environment. The Leapfrog Geothermal model shows that the gas-condensate field presents a structurally complex architecture, where hydrocarbons and water accumulate in an relatively permeable reservoir. Well data exhibit a constant geothermal gradient, indicating conductive heat transfer. Based on geochemical data and hydrological analyses, it is identified that meteoric recharge occurs in the Andean orogenic belt and fluid flows from NW to SE. TOUGH2 numerical simulations are developed to generate a natural state model and geothermal production scenarios, which give an estimation of water extraction in the field. The thermal and hydraulic parameters were extracted from published experimental and well data. In order to simplify this first geothermal model, and reduce the number of parameters, it is assumed that the field is completely saturated with water. The natural state model temperature field is concordant with measured well data and simulated mass flow direction confirm expected patterns. Production scenarios demonstrate that it is possible to extract water at more than 90 °C without thermal breakthrough during the 30 years simulation. Thermal power calculations yield two optimistic scenarios with more than 30 MWℎ of heat production, and a conservative scenario with approximately 6 MWℎ. The conservative scenario provides a better approach to reality with current water production. Thus, this project presents the basis for further studies on geothermal development in actively exploited hydrocarbon fields.