Numerical modelling of geothermal reservoir in Dongli Lake area, China

Abstract

Dongli Lake geothermal system is a typical low- to medium-temperature sedimentary basin where a traversing fault conducts heat and fluid. Most of the geothermal wells are distributed along this fault. Various data were collected for this study, such as seismic profiles, drilling data, stratigraphic data and historical dynamic monitoring data. A 3D geological model was established using Leapfrog Geothermal software, the best place for drilling was located and two wells were sited on the western part of the study area. Since there is no obvious hydraulic connection between the western and eastern sides of the fault, the western part was chosen for more specific study due to the well known geology and production history. Based on the conceptual model, a numerical model of the study area was created with PetraSim. Numerical model was calibrated to reach the natural state, therefore the model parameters can be used as initial conditions for production. After the numerical model calibration, the observed and simulated data showed a good match. The mean relative error of the temperature simulation is 33% while the mean relative error for pressure simulation is 9.7%. The calibration result of Jxw reservoir’s X, Y permeability is 3.0×10-13 m2 , the Z permeability is 3.0×10-14 m2 and wet heat conductivity is 2.9 W/(mꞏK).