South Sumatra Basin Research Articles

An Implementation of XGBoost and Random Forest Algorithm to Estimate Effective Porosity and Permeability on Well log data at Fajar Field, South Sumatera Basin, Indonesia

<p class="Keywords">New approaches and methodologies have been developed to petrophysical analysis from well logs data using machine learning. Through this method, a machine learning algorithm is applied to predict the accuracy of the model on effective porosity (∅e) and permeability (K) which implemented using Random Forest and Xtreme Gradient Boosting (XGBoost) algorithm. The dataset used is obtained from well logs data that have been calculated petrophysical analysis. This study proposes the algorithm which is known to be effective in providing accurate predictions in a short time in estimating effective porosity and permeability. The results of the prediction model is optimized by GridSearchCV (GS), validated by the k-fold cross-validation, and evaluated using R2 score and Root Mean Square Error (RMSE). Model is applied to 5 research wells in Fajar Field of south Sumatra Basin, Indonesia with 4 variations of well training and well testing data split. The best evaluation results obtained with evaluation metrics were up to 0.90 (R2 score) and 0.01 (RMSE) for effective porosity and permeability by Random Forest, while evaluation metrics are 0.90 (R2 score) and under 0.68 (RMSE) for effective porosity and permeability by XGBoost. There is no decrease in accuracy until the last variation so that it can be concluded that these algorithm models can effectively estimate reservoir porosity and permeability in the field and contributed an alternative for the problem of many incomplete and dissimilar well logs data.</p>

Harnessing 3D seismic data for mapping natural CO2 distribution: Paving the way for future CCS/CCUS implementation in the Lower Talang Akar Formation, Jabung Block, South Sumatra Basin

Hydrocarbon reservoirs saturated with CO2 are naturally widespread in the Lower Talang Akar Formation (LTAF) and deposited in the Jabung Block, South Sumatra Basin, Indonesia. The different CO2 saturation contents stored in the reservoirs pose a challenge to planning future carbon capture and storage (CCS) and carbon capture, utilization, and storage (CCUS) in the area. This study integrates poststack 3D seismic data and existing wells in the western part of the Jabung Block. It utilizes seismic attribute methods such as sum of negative amplitude, relative impedance, variance, and ant tracking to predict the origin, saturation, and distribution of CO2-saturated hydrocarbon accumulations in the sandstone reservoirs of the LTAF. The results show that CO2 originated from the Betara Deep source rock in the study area's eastern side and migrated to the reservoirs through major northwest–southeast-trending fault zones. The saturation of CO2 in the reservoirs is mainly controlled by the distance from the source and the reservoir depths, faulting, and fracturing intensity. The fields closer to the Betara source rock tend to be filled with higher contents of CO2 saturation. The results provide valuable guidance in CO2 identification and mapping for future CCS and CCUS implementation in the study area.

Evolution of Sequence Stratigraphy and Paleogeography, Case Study: M2 Member of the Muara Enim Formation

Sequence stratigraphy related to accommodation space as an area of potential sediment accumulation that is influenced by fluctuations in sea level and subsidence of the basin floor. Paleogeography, on the other hand, is the study of physical geographic features and their evolution throughout geological periods. The aim of this work is to shed light on the relationship between paleogeographic evolution and sequence stratigraphy, as well as coal accumulation in the South Sumatra Basin. The method used are geophysical logs and cores analysis to determine the system tracts, types of system tracts, and stratigraphic sequences, lithofacies and sedimentary facies analysis, paleogeographic analysis using modified single-factor and multi-factor and them mapped using IDW as a geostatistical method. The results indicate that the study area comprises four system tracts, namely TST-1, HST-1, TST-2 and HST-2. In TST-1 and TST-2, the rate of peat formation is balanced with the rate of accommodation space formation, resulting in continuous and very thick coal accumulation. In HST-1 and HST-2, the rate of accommodation space formation exceeds the rate of peat formation, leading to continuous coal accumulation that is quite thick to very thick. Sequence 1 consists of lagoon and tidal/mouth/distal bar paleogeographic unit with sand/shale ratio range 0.217 to 0.247. Sequence 2 consists of lagoon paleogeographic units with sand/shale ratio range 0.046 to 0.05.

Transgression patterns of Muara Enim Formation at Tanjung Agung Village based on stratigraphic data measurements

Abstract Muara Enim Formation is one of the formations which is composed in the South Sumatra Basin in the Late Miocene Epoch. It has a specific lithology which shows how the conditions of the depositional environment were the formation was deposited. The purpose of this research is to determine the pattern of transgression and regression of Muara Enim Formation. Transgression and regression patterns are used to determine how the shoreline moves. It is caused by the supply of sediment material. The finer sediment material is deposited and the smoother the movement of the material towards the land, showing the indication of transgression, and vice versa. This research uses analytical-interpretative as the method, which is using the result of sampling analysis and then interpreting how the pattern of transgression and regression are changed. This method is used to determine the physical properties of the lithology composing the Muara Enim Formation. Based on field observations on the Air Enim River, it is known that the Muara Enim Formation is composed of lithology dominated by fine grain size (claystone) to medium grain size (tuffaceous sandstone) with thin coal in several locations. Based on field outcrop (surface data) it is known that the claystone lithology is thickened to a younger layer (about 2.5 m thickness) with massive sedimentary structure. It is interpreted that the Muara Enim Formation was deposited in a transgression pattern in a depositional phase which was influenced by sediment supply factors and weak depositional currents.

Geochemical Characterizations of Crude Oils in Pendopo High and Limau Graben, South Sumatra Basin

There are several oil fields in Pendopo High and Limau Graben, South Palembang Subbasin, South Sumatra Basin. Crude oils from the Pendopo High and Limau Graben have been analyzed using geochemical methods. Some or all of the following analyses were completed on twenty-four oils. Two analysis methods, namely the δ13C isotopic and biomarker compositions have been used to classify the oil types. Most of the oils are isotopically more depleted in δ13C sat (> -28‰) relative to the other four oil sample counterpart of the Pendopo High. All oil samples from The Pendopo High have Pr/Ph values < 4 and those from the Limau Graben > 4. In addition, biomarker ratio for hopanes/steranes from the Limau Graben shows small values compared with the Pendopo High. Geochemical cross plots of probabilities can also be used to distinguish oils derived from different source inputs. In the Limau Graben, tricyclic terpane data shows terrestrial patterns, while the Pendopo High shows deltaic patterns. The Limau Graben is derived from humic kerogen, while the Pendopo High is more towards mixed kerogen (humic and sapropelic kerogen). The depositional condition in the Limau Graben is anoxic to suboxic to oxic and mostly oxic condition, predominated by higher plants. While Pendopo High condition is anoxic to suboxic, predominated by algae. Oil in the Pendopo High is interpreted to be deltaic oil, whereas oil in the Limau Graben is a typical fluvial.

Stochastic Inversion in Determining the Distribution of Petroleum Carrying Sandstones in the "JS" Field of the South Sumatra Basin

The "JS" field is a field located in the South Sumatra Basin, where the field has good prospects for the distribution of petroleum-bearing sandstone. The target of this research is the Air Benakat formation. This research uses the stochastic seismic inversion method to determine the probability of finding petroleum in sandstone. Stochastic seismic inversion has the advantage that it can overcome thin layers and can reduce existing data misalignments. So stochastic inversion can overcome the shortcomings of other seismic inversions, especially model-based seismic inversion which is the initial model for stochastic seismic inversion. Stochastic seismic inversion produces several realizations by showing uncertainty so as to get results that are close to the actual situation. Probability map of oil-bearing sandstones located in the north and east of the study area. with the slice results obtained for the acoustic impedance range of 8517-9051(m/s)*(g/cc) and oil sand probability with a value range of 0.61-0.78%.

Development of CO2 Hub-Clustering Management in The South Sumatra Basin

Development of CO2 Hub-Clustering Management in The South Sumatra Basin

Provenance and Petrographic Analysis of Paleogene Sandstones in the Bukit Tigapuluh Area, Jambi Subbasin, Indonesia

The study investigates the provenance of Paleogene sandstone deposits from the Lemat Formation in the Lubuk Lawas and Lubuk Bernai sections of the Bukit Tigapuluh area, Jambi Subbasin, South Sumatra Basin, Indonesia. The research aims to elucidate the formation history and stratigraphic evolution of these sedimentary rocks through detailed petrographic analysis. Twenty-two rock samples were analyzed to classify the sandstones and determine their source rock types and tectonic settings. The results indicate that the sandstones are primarily classified as Lithic Arkose, Arkosic Subarkose, Feldspathic Litharenite, Silty Claystone, Sublitharenite, and Subarkosic Wacke. The provenance analysis suggests that these sandstones originated from a tectonic setting of a recycled orogenic zone, comprising quartzose recycled, transitional recycled, and mixed sources, indicating a combination of primary and recycled orogenic materials. Paleocurrent analysis from sedimentary structures in the Lubuk Bernai area suggests deposition directions from the southwest and southeast. This study provides significant insights into the paleogeography and tectonic evolution of the Lemat Formation within the Jambi Subbasin. Further research should focus on integrating geochemical data to refine the understanding of sedimentary provenance and tectonic implications.

Comprehensive Facies Analysis and Depositional Environments of the Kikim Formation, Garba Mountain, South Palembang Subbasin, Indonesia

This study provides an exhaustive facies analysis of the Kikim Formation within the Garba Mountain area of the South Palembang Subbasin, emphasizing the stratigraphic significance and depositional environments during the Paleogene period. Utilizing field data collected from the Bumi Agung and Batu Belang measurement lines, this research categorizes various lithofacies using Miall’s (1978) classification scheme, identifying eight distinct lithofacies and four facies associations indicative of a predominantly fluvial depositional setting. The results depict a detailed sedimentological framework, showing that the Kikim Formation was characterized by a braided river system with significant gravel and sandstone deposits. This analysis not only sheds light on the geological history and processes shaping the South Sumatra Basin but also enhances the understanding of its potential hydrocarbon reservoirs. By detailing the lithological diversity and facies distribution, this paper contributes to the broader geological knowledge required for effective exploration and management of the region's natural resources.

Determination of Hydrocarbon Production Zones using Well Logging Data in the "North_Rawa" Well of the South Sumatra Basin

Petrophysical analysis with well logging is carried out to determine the value of petrophysical parameters of rocks in the formation. Then to find out information about the subsurface structure as well as the depth zone of layers containing hydrocarbons and the types of hydrocarbons from the production field. In this research, an evaluation of reservoir formation was carried out in the North_Rawa field of the South Sumatra Basin, based on petrophysical log analysis from data from three wells in the North_Rawa field. Reservoir identification results from physical rock parameters such as porosity, shale content, water saturation and permeability obtained from formation evaluation calculations. Porosity is calculated to determine the pores, shale content is calculated to determine the volume of shale in the reservoir, water saturation is calculated to determine the water content in the formation, and permeability is calculated to determine the rock's ability to pass fluid. The results of petrophysical calculations were obtained in the hydrocarbon prospect zone in the North- rawa 1 well at a depth of 3387.5 – 3938 feet, the North- rawa 3 well at a depth of 2667.5 – 3735.5 feet, the North- rawa 4 well at a depth of 2759.5 – 3775 feet. The average porosity values for each well are 8%, 15.4%, 16%. The average shale content value for each well is 61%, 48%, 53%. Average water saturation values are 61%, 54%, 68%. Average permeability values 46.7 mD , 98.9 mD , 3.38 MD. The hydrocarbon prospect in the research well contains natural gas and oil hydrocarbons with sandstone and shale formation lithology.

Deposition Environment Interpretation of Lemat Formation in the West Tanjung Jabung, Jambi Province

The study of facies analysis and interpretation of the depositional environment of the Lemat Formation located on Bukit Tigapuluh aimed to clarify the problems found in Paleogene sediments in the South Sumatra Basin. The results of research on facies analysis and interpretation of the depositional environment of the Lemat Formation will provide an explanation and description of the history of the formation and stratigraphic evolution of Paleogene-aged sedimentary rocks in the South Sumatra Basin as reflected in their lithological and facies characteristics. A detailed analysis of fluvial facies was carried out in the West Tanjung Jabung area, Jambi Province. A stratigraphic cross-section was prepared with an accumulated thickness of ± 25 m. The stratigraphic section included two rock deposits, namely sandstone-quartz deposits and conglomerate deposits. Analysis of lithofacies and architectural elements of the study area indicated a fluvial depositional environment. The resulting architectural elements consisted of six associations: channel (CH), scour hollows (HO), gravel bedform (GB), sediment gravity flows (SG), sandy bedform (SB), and floodplain fines (FF). The dominance of sedimentary material, which tends to be coarse, and the many facies associations GB, SG, and SB indicated many river bars and were characteristic of braided rivers. The obtained interpretation of the depositional environment was Conglomerate deposits in the Alluvial Fans System with Gravity Flow River environment or gravel bed braided river, and sandstone-gravel deposits in the shallow environment or gravel bed braided river.

CHARACTERISTICS, RANKING, AND POTENTIAL OF COAL ON SEAM H AND SEAM H2

Coal is a complex solid object consisting of several chemical elements and comes from plants that are deposited in a basin. The South Sumatra Basin is a basin with the presence of the Muara Enim Formation which is known as a coal-bearing formation. In this research, secondary data was used in the form of proximate analysis, ultimate analysis, and combustion properties analysis results in determining the characteristics, ranking, and potential of coal in the research area. Based on ASTM D 388 – 05 classification, coal in seam H has a Subbituminous B Coal ranking, while seam H2 has a Subbituminous A Coal rating. Based on the parameters in assessing the coal potential use for coal-fired power plants according to Thomas, 2013 in Suhat, et al., 2020, coal in seam H and seam H2 does not support the utilizations, but solutions can be carried out in the form of rewashing sample, coal drying, and coal blending.

DETERMINATION OF HYDROCARBON ZONE AND DEPOSITIONAL ENVIRONMENT FACIES IN TALANG AKAR FORMATION, SOUTH SUMATRA BASIN AT "EPURA" FIELD

The EPURA field is one of the oil and gas producing fields in the South Sumatra Basin, where well completion has been carried out in the Talang Akar Formation, and the production test results are interpreted to mean that in wells EP-13, EP-14, EP-15, EP-16, EP-17 and EP-23 contain several reservoir zones that have the potential to contain hydrocarbons. This research with facies interpretation analysis uses data from six wells (wireline, mudlog, RCAL and lithology data), so it is hoped that it can provide more detailed information for the development of an oil and gas field. The analysis carried out is in the form of facies analysis, depositional environment, electrofacies and facies correlation. From the research results, it was found that the Talang Akar Formation has depositional facies in the form of a fluvial, which in this study is the Lower Talang Akar Formation with depositional facies in the form of channel, Crevasse Splay, point bar and flood plain. Based on the analysis results, the Talang Akar Formation is divided into 3 reservoir zones, namely Zone EP-1, EP-2, and EP-3. After going through all stages of petrophysical analysis, it was found that zones with high hydrocarbon potential were found in wells EP-13, EP-23 and EP-16. The wells with low hydrocarbon potential are EP-14, EP-15 and EP-17 wells. The zone of highest hydrocarbon potential in prospect wells is in the EP-1 zone with a Crevasse Splay facies association and has thick sandstone lithology characteristics with medium to fine grain size.

Rock Mineralogy Analysis of Airbenakat Formation to Map the Characteristics of the Reservoir Rocks in each Depositional Environment

The Airbenakat Formation is a sandstone reservoir which is one of the oil reservoirs located in Sumatra and is part of the South Sumatra Basin. The mineral composition of the sandstone reservoir in the Airbenakat Formation consists of quartz minerals as rock grains, clay as matrix and is often identified as cement, while carbonate as rock cement. Based on lithofacies observations, the depositional environment of the Airbenakat Formation consists of: Volcanic Alluvial Fan, Lake, Braid Bar, Braided Channel, Braid Deltaic Environment, Mud Flat, Tidal Sand Bar, Tidal Environment, Shallow Sea, and Deep Sea. This research was conducted on 2 (two) oil fields, namely MRP dan TPN which have different depositional environments but are included in the Airbenakat Formation as part of the South Sumatra Basin.The analyzes used in this study include X-Ray Diffraction (XRD) analysis, petrography, and Scanning Electron Microscopy with Energy Dispersive X-Ray Spectroscopy (SEM/EDX). Analysis of the mineralogical content of the Airbenakat Formation will assist to determine the performance of chemical injections such as injection of anionic surfactant. The anionic surfactant used for chemical injection in Airbenakat Formations will be optimal if the content of smectite and calcite minerals can be ascertained. The presence of smectite and calcite minerals will affect the results of anionic surfactant injection. This research shows the results of anionic surfactant injection on the presence of smectite and carbonate in the injected core.

A preliminary analysis of natural CO2-saturated gas sands distribution in the Gemah Field-Jabung Block, South Sumatra Basin, Indonesia, by using simple seismic attributes

The discovery of CO2-saturated gas in sandstone reservoirs of the Lower Talang Akar Formation (LTAF) in the Jabung Block of South Sumatra Basin is a significant exploration risk that affects development plans. Gemah Field is one of the fields that produces CO2-saturated gas in the area. The field has several oil rims that can be optimized for production by using carbon capture, utilization, and storage (CCUS) enhanced oil recovery (EOR). This paper discusses a preliminary analysis of the natural CO2-saturated gas sands distribution in the FS3 interval of Gemah Field by using simple seismic attributes. The results can be used for guiding the feasibility analysis of CCUS-EOR implementation and mitigation of drilling risk of subsequent developments wells. Poststack seismic attributes and inversion analysis were performed and constrained by data from 64 wells in the FS3 interval. Although these two methods give similar distribution of sandstone reservoirs, this study finds that the sum of negative amplitude (SNA) attribute is better because there is a linear relationship between SNA with sand thickness and CO2 saturation. High CO2 saturation gas reservoir zones are observed along the highly faulted areas. CO2 saturation decreases away from the faulted areas and follows the northeast–southwest direction of reservoir deposition. The identified high CO2 regions can be considered as zones of potential CO2 sources for CCUS-EOR. The low CO2 areas are a potential location for a subsequent drilling well to obtain cleaner gas reservoirs with low CO2 saturation.

The marine fossils and paleoecological significance of the Southern edge of South Sumatra Basin in Linggapura Lampung, Indonesia

The South Sumatra Basin is identified as a Paleogene-Neogene sedimentary basin with Mesozoic basements. It is located in the eastern Barisan Mountains, covering Jambi, South Sumatra, and Linggapura (Lampung), Indonesia. Linggapura represents the southernmost part of the South Sumatra Basin. The basin consists of two well-known rock formations, namely the Talangakar and Baturaja Formations. In this study, we investigated these formations through fossil records and paleoecological interpretations. Our investigation was based on measured stratigraphy and fossil observations along the Way Penandingan River in Linggapura, Lampung. We discovered that the bottom of this area consists of Cretaceous granitoid, which forms a nonconformity with the sedimentary rocks in this area. The Talangakar Formation in this region comprises quartzy-grained sandstone and conglomerates containing fossilized remains of terrestrial plants/vegetation. These plant fossils have undergone coalification, with some being silicified. The Batujara Formation in Linggapura is dominated by bioclasts, primarily consisting of Miocene shoreface-lagoonal larger benthic foraminifera, along with other marine and ichnofossils. Based on our findings, we suggest that the paleoecological condition of this area is associated with shoreline transgression during the Oligo-Miocene period. The hotter Miocene climate contributed to a rise in sea levels, resulting in shoreline transgression. Gradually, the area transformed from a terrestrial environment to a highly bioproductive marine environment, at least from the Late Oligocene to the Early Miocene. This study represents an important milestone in better understanding the paleoenvironmental conditions at the edge of the South Sumatra Basin throughout its geological history.

The Comparation of Water Saturation Approaches to Reveal a Low Resistivity Reservoir Potential Case in Gumai Formation, South Sumatra Basin

The LRLC reservoir zone has been identified in SN-3 well, at the DAP-1 interval on Gumai Formation. This interval has a low resistivity value from 3-5 ohm.m and the drill stem test (DST) results show oil with gas without water. This study is objected to identify the causes of LRLC reservoir in gumai formation and finding a suitable sw calculation method. Some data such as well logs, reports, cores, and XRD are used to calculate petrophysical parameters such as Vsh, Phie, and Sw, and would be validated by DST data. Water saturation (Sw) calculations from Archie and the CEC method (Waxman Smits, Dual Water, Juhasz) were performed and the results were compared. The results showed that the main cause of the DAP-1 interval LRLC zone was the presence of clay minerals consisting of mixed layers (Illite/smectite). These clay minerals will be associated with high cation exchange capacity (CEC) values, with the value 70 (meq/100g), which can increase conductivity and reduce resistivity values. Based on lumping the more optimistic results of sw calculation from Waxman Smits Sw method (Sw based on CEC method). The DST data on the SN-3 well does not have water test data, so the calculation of the Sw value that is close to the Swirr value is considered the most suitable Sw for the low resistivity reservoir conditions of the Gumai Formation in the study area. The best practice for low resistivity reservoir for suitable petrophysical calculation is necessary to pay attention to the rock lithology conditions, the presence of mineral clay, and determining suitable Sw appropriate to the reservoir conditions

Basaltic Lava Characteristic in Goa Pandan Area, Sukadana, East Lampung: Inferences from Stratigraphy and Petrography Analysis

The presence of extensive basalt formations in East Lampung has its own attractions in the field of geology, particularly the presence of Goa Pandan as a lava cave and tourist attraction in East Lampung. The presence of basalt lava in the southern part of the South Sumatra Basin has drawn attention to the presence of this lava, but detailed research on the characteristics of the lava and its formation process is still very rare. This study aims to determine the eruption period of the basalt lava and magma evolution process based on the correlation between lava stratigraphy and petrography analysis. Field observations show a lava sequence that forms Goa Pandan. Each lava sequence is characterized by autobreccia and vesicular structures on the surface. In addition, the presence of columnar joints, sheeting joints, massive lava, and other additional structures indicate the characteristics of low-viscosity basalt lava. The presence of mineral structures and abundance under the microscope clearly shows the magma formation process when basalt lava flowed on the surface. Resorption-overgrowth of plagioclase and pyroxene minerals indicates an open system when basalt lava flowed on the surface. In addition, the presence of zoning and patching in plagioclase minerals indicates that magma variability is influenced by temperature. The documentation of this lava stratigraphy can serve as a basis for further understanding of magma characteristics and formation processes. There is still much geological work that can be done in the research area to get a detailed picture of the evolution process of magma and the presence of basalt lava in this area.

Seismic Analysis of RMS Amplitude Attributes to Identify Hydrocarbon Potential in Field "X" of Jambi Province Indonesia

Indonesia has many potential oil and gas basins. Seismic attribute analysis of RMS Amplitude (Root Mean Square) was conducted in the Betung area, Jambi sub-basin, South Sumatra Basin. The reservoir characterisation technique used in this study is rms attribute analysis which can show changes in the lithology of the study layer. Seismic attributes were extracted from 2D pre-stack time migration (PSTM) seismic data. This study also takes BTJ-210 log data as interpretation and determines the reservoir thickness at the target. Based on the seismic attribute analysis with rms, it is verified that the reservoir is indeed detected within the analysis window of 10 ms, 20 ms, 30 ms, 40 ms and the possible distribution of the reservoir is in horizon 3 and horizon 4 which has a high range of amplitude values and is in a high range zone or higher area than the surrounding area. The results of this seismic attribute analysis can show the hydrocarbon prospect zone and the potential for new well development in the study area, which is located in Horizon 3 and Horizon 4 at a depth of 227 to 250 metres south of the study area.

GEOLOGICAL INTERPRETATION OF 2D GRAVITY MODELING IN TULUNG SELAPAN AREA AND SURROUNDINGS, SOUTH SUMATRA BASIN

The South Sumatra Basin is a prolific oil and gas basin. The Tulung Selapan area, which is to the east and part of the South Sumatra Basin, is considered to have hydrocarbon potential. Several sub-basins, including the South Palembang and the North Palembang sub-basins, exist in the region. One of the geophysical methods for determining the presence of sedimentary sub-basins, structural patterns, and bedrock is the gravity method. The purpose of this study is to determine the structural pattern and interpret the subsurface geological model of the Tulung Selapan area using 2D modeling. The complete Bouguer anomaly (CBA) reveals circular and relatively northwest-southeast trending patterns, ranging from +33 mGal to +62 mGal. 2D gravity forward modeling results in eight successive rock layers. From top to bottom, the uppermost layer is swamp sediment with a mass density of 2.1 g/cm3, followed successively by the sedimentary rocks of the Kasai Formation (2.28 g/cm3), the Muara Enim Formation (2.32 g/cm3), the Air Benakat Formation (2.39 g/cm3), the Gumai Formation (2.3 g/cm3), the Baturaja Formation (2.48 g/cm3), and lastly a layer with a density of 2.7 g/cm3, which represents the bedrock. Due to the limited depth of 2800 m in 2D forward modeling, it is unable to identify the source and reservoir rocks. The seal rock (caprock) is interpreted to be shale from the Gumai Formation at an average depth of 1.53 km. Based on Second Vertical Derivative (SVD) analysis, 2D modeling identifies the presence of geological structures with normal faults.