Analysis of Soil Deformation Due to Oil and Gas Exploration and Hydrocarbons Micro Seepage in Ngasem District, Bojonegoro Regency

Abstract

Land subsidence is the result of the extraction of liquid in the pores of the rock from the compression of the sediment. The decrease occurred due to the exploitation of oil and gas wells in the area which took and caused reduced sediment compression. Aside from the result of excessive extraction of hydrocarbons, hydrocarbon micro seepage can also trigger an anomaly in the ground level. This anomaly is due to the abundance of hydrocarbons in the reservoir and the dynamic nature of oil and gas accumulation, which results in the absence of a perfect rock seal. This study aims to determine the average rate of subsidence in Ngasem District and to analyze the relationship between soil deformation and oil and gas exploration activities and hydrocarbon micro seepage. The method used in this research is InSAR Time Series with LiCSAR Sentinel 1 SLC and Generic data. Atmospheric Correction Online Service (GACOS) which was used from 2014 to. Meanwhile, maps of the distribution of hydrobarone micro seeps were obtained from Exxon Mobil and Exploration Wells for the East Java Basin were obtained from the Ministry of Energy and Mineral Resources. The results showed that the deformation of the land surface in the Ngasem sub-district was very diverse due to the presence of geological structures, exploration wells and potential seepage of micro-hydrocarbons. From the results of deformation processing in the Ngasem District area, it has the highest rising speed in the study area at 77mm/year while for the greatest decrease at -85 mm/year. Exxon Mobill’s exploration wells experienced a subsidence of -30mm/year, while the potential for micro-hydrocarbon seepage increased by 60mm/year. From the results of the analysis of the decline that occurred in exploration wells due to oil and gas exploitation.