Publications

Subsurface temperature causes many impacts in crust rock, ranging from hydrocarbon generation, geothermal energy prospect, mineralization, rock diagenesis and even geohazard. In this paper, we propose a modeling strategy for profiling subsurface temperature and have applied it for profiling the subsurface temperature of East Java. The proposed subsurface temperature modeling uses various input data, i.e.: thermal conductivity of samples in various lithologies and formations, surface and gradient temperature from the northern part to the southern part of East Java and subsurface geological model from gravity modeling constraint by well or seismic. The thermal conductivity model is calculated based on constraint gravity modeling and thermal conductivity measurement of samples in each formation and lithologies of the East Java basin. Temperature information are collected not only from previous well reports but also from using direct measurements from Ujung Pangkah, Gresik, Sidoarjo, and from Porong to Penanggungan mountain, including the Malang Area. All of the measurements are combined together from shallow, middle and deep well temperatures, including gravity modeling constraint by well and surface geology. The subsurface model is then combined by thermal heat conductivity of various lithologies. The temperature modeling is carried out by finite difference of Fourier’s law and it is assumed that the thermal heat of Earth is constant or steady state. The numerical modeling, based on finite difference and output of subsurface temperature profile, is a 2-dimensional temperature profile of East Java. The results show an interesting profile of subsurface temperature in the middle part of East Java that contains some anomalies of temperature which may be correlated by volcanic activity and impact of fault existence in this area. A 2 dimensional temperature profile beneath the 120 km line is presented in this paper.