Abstract:In early 2017, the geothermal system in the Suli and Tulehu areas of Ambon (Indonesia) was investigated using a gravity gradient tensor and analytic signal. The gravity gradient tensor and analytic signal were obtained through forward modeling based on a rectangular prism. It was applied to complete Bouguer anomaly data over the study area by using Fast Fourier Transform (FFT). The analysis was conducted to enhance the geological structure like faults as a pathway of geothermal fluid circulation that is not visible on the surface because it is covered by sediment. The complete Bouguer anomaly ranges of 93 mGal up to 105 mGal decrease from the southwest in Suli to the northeast in Tulehu. A high gravity anomaly indicates a strong magmatic intrusion below the Suli region. The gravity anomalies decrease occurs in the Eriwakang mountain and most of Tulehu, and it is associated with a coral limestone. The lower gravity anomalies are located in the north to the northeast part of Tulehu are associated with alluvium. The residual anomaly shows that the drill well TLU-01 and geothermal manifestations along with the Banda, and Banda-Hatuasa faults are associated with lowest gravity anomaly (negative zone). The gravity gradient tensor simulation and an analytic signal of Suli and Tulehu give more detailed information about the geological features. The g zz component allows accurate description of the shape structures, especially the Banda fault associated with a zero value. This result will be useful as a geophysical constraint to subsurface modeling according to gravity gradient inversion over the area.
The purpose of the research was to identify policy formulation, policy implementation, policy environment, and performance professional improvement of teachers in the elementary school of YPPSB. This policy research used a qualitative approach. The data of this research was collected by in-depth interviews, observation, documentation study. Analysis of data using a technique of organizing data, coding, verification, and conclusions). This research's findings are as follows: (1) policy of the teacher professional improvement of SD YPPSB - PT. Kaltim Prima Coal follows a Top-down approach and bottom-up approach model of formulation policy, (2) the implementation of teacher professional improvement policy successfully conducted to its vision, mission, and goal; (a) recruitment of qualification teachers, (b) Conducting and includes teachers in the education and training, (c) professionalization of teachers through KKG and MGMP, (d) facilitating teachers to continue their studies S2, (e) educational supervision, ( f) course intensification, (g) weekly meeting, (h) reward, and (i) allowance. Policy recommendations that can be given are as follows, (1) Principal of SD YPPSB needs to increase teachers' professional development, primarily through forms of training, (2) the Education Department to develop comprehensive education, especially for private schools, and (3) The Government continually strive to find alternatives to increase the professionalism of teachers.
Seismic data processing is one of the three stages in the seismic method that has an important role in the exploration of oil and gas. Without good data processing, it is impossible to get seismic image cross section for good interpretation. A research using seismic data processing was done to update the velocity model by horizon based tomography method in SBI Field, North West Java Basin. This method reduces error of seismic wave travel time through the analyzed horizon because the existence velocity of high lateral variation in research area. There are three parameters used to determine the accuracy of the resulting interval velocity model, namely, flat depth gathers, semblance residual moveout that coincides with the axis zero residual moveout, and the correspondence between image depth (horizon) with wells marker (well seismic tie). Pre Stack Depth Migration (PSDM) form interval velocity model and updating using horizon-based tomography method gives better imaging of under-surfaced structure results than PSDM before using tomography. There are three faults found in the research area, two normal faults have southwest-northeast strike and the other has northwest-southeast strike. The thickness of reservoir in SBI field, North West Java Basin, is predicted between 71 to 175 meters and the hydrocarbon (oil) reserve is predicted about with 22.6% porosity and 70.7% water saturation.
The 4D gravity or time lapse gravity has been used many reseracher to identify fluid injection in oil reservoir. The objective of this study is to find the better way in interpreting 4D gravity anomaly due to fluid injection around the reservoir. Radial Derivatives are derivative values of gravity anomalies against horizontal distances in the radial direction. Radial inversion is a two-dimensional inversion of lines with radial directions resulting in a 3-dimension model. Time lapse microgravity research have been performed in "X Oil Field" with amount of 604 data point covering area of 4000 m x 5000 m. This Radial derivative and Radial inversion have been aplied at an injection well of the X oil field. The yield show that 4D gravity anomaly value due to injection is 0.02 mGal to 0.36 mGal. Radial derivative value in the area is 0 micro Gal/cm to 0,012 mGal/meter. Radial inversion shows radius of fluid front movement is 304 meters to 1120 meters. Radial derivative and Radial inversion have been proven fairly good to identify injected fluid movement in the reservoir.
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