PROCEEDINGS JOIN CONVENTION BANDUNG (JCB) 2021 December 1 st – 3 rd 2021 1 IDENTIFICATION OF THE SHALLOW HYDROCARBON ZONE USING TILT DERIVATIVE GRAVITY DATA AND THE WENNER-SCHLUMBERGER CONFIGURATION METHOD IN RANTAU PEREULAK AREA, EAST ACEH, ACEH PROVINCE K. Alfaiz 1 , Imaduddin 2 , M.K. Jibran 1 , Y. Assyifa 1 , Z. R. Qauvani 1 , S. J. Fahira 2 , R. R. Putra 1 , N. Khaira 2 , S. Futhra 1 , A. Zahran 1 1 Department of Geophysical Engineering, 2 Department of Geological Engineering, Universitas Syiah Kuala, Banda Aceh 23111 Indonesia ABSTRACT The increasing of human needs for oil and natural gas caused the exploration and production are in crucial to be carried out, especially in Aceh. Since the conflict begun between Indonesian Government and GAM, exploration activities have also begun to be rarely carried out. A well of an old oil, which was operated by a Dutch company is being neglected currently. An illegal drilling carried out by the community in Rantau Peureulak area of East Aceh has proved the potential reserves of this old oil well. The gravity method can be applied in the early stages of hydrocarbon exploration to determine the location of hydrocarbon potentials based on variations in the Earth's gravitational field. Through the gravity satellite, it found the anomaly data of free air is obtained with a value range of -31.7 - 80 mGaL. Assuming the rock density in the study area is 2.67 gr / cm3, a Bouguer correction is made to obtain the gravity value by taking it into account the effect of rock mass around the measurement point. The gravity value is later going to be used to calculate the simple Bouguer anomaly value by reducing the free air anomaly value with the Bouguer correction value. The range of values resulting from the simple Bouguer anomaly in the study area ranged from - 92.6 - 51.6 mGa. Based on the results of the SRTM and Tilt Derivative overlay and geological structure showed that the research target location is a zone with a value of 1.5 mGal and there are several minor faults which are assumed to be fault lines where shallow hydrocarbons migrate to the surface. The lateral distribution of shallow hydrocarbon potential shows the presence of 4 (four) rock's layers, namely topsoil, loamy sand, muddy sand, and alluvium sediment with the distribution data of resistivity values obtained from 6 - 100 Ωm. An indication of the presence of shallow hydrocarbon fluid is found in alluvium sediment in the form of sand's layer with a resistivity value of 8 - 40 Ωm at the depth of 60 m. Analysis studies of shallow hydrocarbon potential distribution in the Rantau Pereulak area of East Aceh need to be carried out to understand the residual of potential realities from the field as a guide in determining the best scenario for field's development. Keywords : Geoelectric, Gravity Satellite, Resistivity, Shallow Hydrocarbon, Tilt Derivative. INTRODUCTION Hydrocarbons which consist oil and natural gas are still the main energy sources that support human activities and interests in various aspects. The more needs, the higher the use of hydrocarbon so that hydrocarbon reserves are needed. Therefore, exploration and production activities are very important to fulfill the needs of oil and gas in Indonesia, especially in Aceh. Since the conflict begun between the Indonesian government and GAM (Free Aceh Movement) exploration activities have also begun to be rarely carried out. Many old oil wells have been abandoned after previously being operated by a Dutch company, one of which was in Peurelak, East Aceh. Most of these oil wells still have potential reserves, as evidenced by the illegal drilling of communities around the area to fill the needs of oil and natural gas in Indonesia, especially Aceh. One of the efforts to increase oil and gas production in the Peureulak area, East Aceh is by mapping shallow hydrocarbon zones by measuring the physical parameters of rocks on the surface and below the surface using both geophysical and geological approaches. Gravity data can be used as the main information in determining the location of 2D geoelectric measurements. Gravity is a leading method in geophysical exploration to determine the presence of hydrocarbon basins based on variations in the value of the acceleration of gravity (Erviantari & Sarkowi, 2008). The gravity method is used as a preliminary exploration of natural resource targets below the earth's surface by describing a two-dimensional (2D) or three-dimensional (3D) profile through processing gravity field anomaly data, which is known as the Bouguer Anomaly. Based on this model, it can be interpreted as the geological structure of subsurface rock layers that are the target of research (Arif, 2016). To better represent the geological structure, Tilt Derivative Gravity can be used to obtain anomaly boundary data, so that the presence of geological structures in the form of major or minor faults can be identified (Praktik & Pertamina, 2020).