SUBSURFACE TEMPERATURE ESTIMATION BASED ON SEISMIC VELOCITY AND ATTENUATION INVERSION RESULT IN GEOTHERMAL FIELD

• Main Author: Hanyfa Maulida, Nanda
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/36305
• Institution: Institut Teknologi Bandung

Temperature is one of the important parameters that need to be known for developing the geothermal field. Various methods have been used to estimate subsurface temperatures in order to obtain the prospect zone. The existence of high dependence of temperature on the velocity and attenuation of seismic waves according to the researches allows the development of subsurface temperature estimation methods by utilizing the results of velocity and attenuation inversion generated from microseismic data. Wayang Windu Geothermal Field is chosen as the research field because the inversion of velocity and attenuation also the well temperature was provided. Estimation are carried out using four different equations, which are from Kampfmann and Berckhemer, Sato, Artemieva and Karato. The results of calculations with these equations produce an overestimate temperature so the resulting value was not good enough to be used for temperature estimation in geothermal field. The regression analysis method is then carried out using Vp, Vs, Qp, Qs and well temperature data. Data distribution patterns show the presence of two clusters with different correlations. The highest regression value in cluster 1 was obtained from multiple regression of Qp and Qs on temperature and cluster 2 from Qp and Vp on temperature. The temperature estimation produced by the regression equation has the best suitability with the well temperature and also shows matching pattern with the isothermal model compared to the results of other equations, so the temperature model of this method is considered the most representative. Based on the temperature model, it is indicated that there are two temperature patterns on the north and south of the field with the boundary at Bedil Horst. There are also indications of water influxes around the WWT and WWD wells in the middle zone of the field and around the MBA well in the north of the field while the upflow zone is only indicated around the wells of MBB and MBD.