Journal of Geoscience, Engineering, Environment, and Technology
Not a member yet
306 research outputs found
Sort by
Machine Learning Application of Two-Dimensional Fracture Properties Estimation
Full text linkFractures are substantial contributors to solute transport sedimentary systems that form pathways. The pathway formed in a fracture has two physical parameters, there are mean aperture and surface roughness. Mean aperture is the thickness of the pathway that the fluid will pass through, and surface roughness is the roughness of the fracture pathway. The two physical parameters of the fracture are important to determine since they affect the permeability value in petroleum reservoir analysis. We developed a machine learning algorithm based on the Convolutional Neural Network (CNN) to predict those two parameters. Furthermore, image processing analysis is performed to generate the datasets. The results show that the CNN algorithm shows good agreement with the reference results. In addition, the algorithms showed efficient performance in terms of computational time. CNN is a type of deep neural designed to perform analysis on multi-channel images that can classify fracture geometry. The best model was determined using a benchmark dataset with a CNN model provided by Keras. The results of experiments conducted on fracture geometry images show that the machine learning model created is able to predict the mean aperture and surface roughness values
Analysis of Water Availability in the Upper Siak Basin Using the GR2M Model Application
Full text linkThe Siak watershed is one of the critical watersheds, where natural disasters such as floods, landslides and erosion often occur in this area. The Siak watershed has 4 main sub-watersheds, namely the Tapung Kanan sub-watershed, the Tapung Kiri sub-watershed, the Mandau sub-watershed and the Siak Hilir sub-watershed. The existence of these 4 sub-watersheds is also not able to meet the water needs of the community due to the rapid development of the region which will then cause the demand for water to continue to increase in line with the rate of population growth, especially in the Siak watershed area. Fulfillment of food needs and population activities is always closely related to the need for water. These demands cannot be avoided, but must be predicted and planned for the best possible use. The purpose of this study is to describe the application of the GR2M modeling and the amount of raw water availability in the Upper Siak Watershed.
The research method used is descriptive quantitative with data collection techniques in the form of map data, rain data, climatology data and field discharge data. And the research location is in the Upper Siak Watershed, namely the Tapung Kiri Sub-watershed.
The results of the study show that 1) GR2M modeling can be applied to the Tapung Kiri Sub-watershed with an R2 performance of 0.41 with a satisfactory interpretation, a correlation coefficient (R) of 0.67 with a strong interpretation, and an efficiency coefficient (CE) of 0.59 with sufficient optimization interpretation. The reliable discharge obtained based on the GR2M modeling data for the availability of drinking water (Q99%) in the Siak Hulu watershed is 15.69 m3/second
Trace Fossils Of The Selorejo Formation, Rembang Zone, North East Java Basin, Indonesia
Full text linkThe Rembang Zone of the North East Java Basin is a zone that develops as a petroleum system and is one of the areas with Indonesia’s largest oil reserves. One of the lithologies in the Rembang Zone is a sedimentary rock carbonated as a marker of marine sediments. The outcrop is continuous and rich in trace fossils, especially in the Ledok and Selorejo Formations. The existence of trace fossil outcrops is crucial for the learning process of earth science, biology, and other sciences, but recently these outcrops have been closed and have become damaged. Their numbers are decreasing due to community mining activities, so unique research on trace fossils in the Rembang Zone must be done immediately. This research aims to discover the variation of trace fossils found in the Selorejo Formation. The methods used are field mapping, measured stratigraphic measurements, rock sampling, and laboratory analysis (sedimentology, petrography, and paleontology). The research shows trace fossils in Planolites, Helminthopsis, Thalassinoides, Conichnus, Chondrites, Macaronichnus, Bergauria, Ophiomorpha, Skolithos, Terebellina, Palaeophycus, and Asterosoma
A geological overview of the limestone members of the Woyla Group of Sumatra, Indonesia
Full text linkMesozoic limestone units of the Woyla group were identified in many places across the northern part of Sumatra, Indonesia. Even though these sedimentary rocks may play an important role as an element of the potential Pre-Tertiary hydrocarbon play of Sumatra, their characteristics are still not well understood. This study tries to fill this research gap and aims to better understand the characteristics of the limestone members of the Woyla group. There are three objectives of this study: (1) to characterise structural features, and deformation of the Woyla Group; (2) to provide sedimentary characteristics of the limestone members of the Woyla Group; and (3) to understand the main influences on the development of the limestone members of the Woyla Group. An integrated geological analyses, including structural scanline analysis, petrographic analysis, and acid digestion analysis, was conducted to achieve the objectives of this study.
Findings from this research show that the limestone members of the Woyla group were strongly deformed, and structural features such as bedded strata, faults, folds, and joints were identified within these rocks. The limestone units of the Woyla group consist of at least six microfacies. These are wackestone, packstone, wackestone-packstone, packstone-rudstone, fossiliferous sandstone, and fossiliferous shale. Depositional processes, sea level fluctuations, tectonisms, and climatic variations are interpreted as the main factors influencing the development and evolution of these limestone units. It is expected that the results of this study could advance our understanding of the Pre-Tertiary carbonate rocks in general, and the Woyla group of Sumatra in particular
Economic And Sensitivity Analysis Stimulation Of Coiled Tubing And Bullhead Combination On A Horizontal Well
Full text linkProduction decreased often occur in Indonesia's oil and gas fields which becomes a problem for oil well exploration. Thus the role of the company demands to be able to re-optimize the flow rate of oil production in the oil and gas field. One of the workover jobs was stimulation. The function of the work was to stimulate the wells mechanically and chemically which aimed to increase the productivity of wells that have experienced a decrease in oil production, in which mechanical stimulation was in the form of coiled tubing units and bullhead used chemical stimulation, namely acidizing and solvent. To prove the economy of the coiled tubing unit and bullhead stimulation work, calculations and analysis of economic indicators such as net present value (NPV), internal rate of return (IRR), and payout time (POT) can be carried out. Where this study aimed to determine the economics of the stimulation project carried out on the horizontal wells of the RD field. The results of the calculation of economic indicators that will be feasible are not like this stimulated workover work project with an investment of US 185,967.166 NPV@ 10% 98,431 USS, POT 3.94 months, PI 3.69, IRR 103%, bullhead acidizing well US$ 8858.31 value NPV@10% 218029 USS, POT 0.95 months, P1 45.16, IRR 1890% and bullhead solvent USS 72745 value NPV@10% USS 248586, POT 0.94 months, PT 52.53, IRR 1822%. Sensitivity analysis on stimulated workover work is carried out by changing the assumptions with 85% and 115% then the results obtained are the oil price value which is the parameter that most influences the NPV value then oil production, and capex. From the results of profit indicator calculations and sensitivity analysis, it can be concluded that the stimulated workover work in the RD field is all feasible because it meets the eligibility requirements of a project
Experimental Study Of Improving The Physical Properties Of Peat Soil Using Sand And Bio-Grouting Techniques With The Assistance Of Bacillus Subtilis Bacteria
Full text linkPeat soil was categorized as soft soil, which means that the soil is in bad condition and problematic when construction was built on it. It was necessary to increase the carrying capacity of peat soils, one of which is chemical stabilization of the soil, by adding additives that can react with the soil and using new environmentally friendly methods.
In this study, samples of peat soil were taken from Buana Makmur Village km55, Dayun District, Siak Regency. The stabilizing agent used was sand as much as 5% by weight of dry soil, Bacillus Subtilis bacteria obtained from the Agriculture Laboratory of the Islamic University of Riau, and also CaCL₂ and Urea. The method for stabilizing the physical properties of peat soil in this study is the Bio-Grouting method, testing the physical properties of peat soil follows the procedures of ASTM (American Society For Testing And Materials) and SNI 1965-2008 for testing methods for determining water content for soil and rock in the laboratory. SNI 1964-2008 test method for soil specific gravity, SNI 8460-2017 geotechnical design requirements, SK SNI -04-05-1989-F fine sand used for construction, SNI-02-2801-1998 urea standard. To test the physical properties was carried out by providing variations in the mixing of bacterial cementation solutions with levels of 0% (without treatment), 5%, 10%, 15%, 20%, and 25% and then allowed to stand for 14 days using a tightly closed plastic container.
The results of testing the physical properties of peat soil found that the peat soil was included in the original soil type with water content = 407.45% and specific gravity (Gs) = 1.30gr, while from the physical properties tests carried out the highest water content occurred in the addition of bacterial cementation solution 10% = 177.2% and the lowest specific gravity occurs when the bacterial cementation solution is added 10% = 1.27gr
Possibilities Study of a Non-condensable Gas Exhaust System through the Condensate Injection Pipe at PLTP Wayang Windu
Full text linkWayang Windu Geothermal Power Plant, located in Pangalengan, Bandung regency, West Java with an installed capacity of 227 MWe has two units to generate electricity and deliver to the Jawa, Madura, and Bali grid. The steam extracted from the reservoir contains non-condensable gas of about 1-1.2% of total steam extracted, with the gas composition is CO2 92%, H2S 2%, NH3 0.1%, and residual gasses 4.9%. Possibilities study of a non-condensable gas exhaust through the condensate injection pipe was created as the efforts in the environmental conservation aspect for reducing carbon released to the atmosphere and reinjected back into the reservoir. This study was simulated in Wayang Windu Unit 2 by calculating the non-condensable gas flow rate from the gas removal system into the condensate injection pipe near of cooling tower blowdown power station area. The analysis result of this study indicates that the non-condensable gas requires a higher flow rate of condensate to dissolve the entire non-condensable gas, and may cause the slug flow pattern which would endanger the condensate pipeline system also destabilize the non-condensable gas exhaust operation process from the condenser through the gas removal system. To deal with this problem, the possibility of exhausting the non-condensable gas produced by the gas removal system can be alternated by flowing its non-condensable gas into a flash absorber system and converting its non-condensable gas into other eco-friendly products and power plant safe
Stress Analysis of Existing Underground Gas Pipeline due to New Road Crossing with ODOL Transportation
Full text linkPipelines are the main choice for transport oil and gas due to its resilience, reliability, safety, and lower cost. Most road crossing pipelines are located underground where protections from the loads can be used such as additional pavement. Underground road crossing pipelines withstand stresses caused by the internal load, earth load, and live load. These loads are affected by the pipe and fluid specifications, soil and environment data, and also the vehicle data. Over dimension and over loading (ODOL) vehicles are a very common problem found in Indonesia. Hence, a stress analysis towards the underground road crossing pipeline being crossed by ODOL vehicles are relevant. A manual calculation of the stress analysis can be done by using API RP 1102: “Steel Pipelines Crossing Railroads and Highways”. A stress analysis using the finite element method (FEM) is conducted using a computer software, namely Abaqus, which also shows the displacement of the pipeline. The case study is an underground road crossing pipeline with depth of 8 feet and uses rigid pavement. The use of rigid pavements over the soil decreases the stress experienced by the pipeline. The results of the total effective stress show a value of 4,785 psi which is still within the allowable range. The stress is found to be directly proportional to the displacement value obtained using FEA. By conducting parametric studies, it is also found that the total effective stress decreases as the burial depth of the pipe is larger
Investigation of Geological Structure Using Magnetotelluric and Gravity Data Optimization on Non Volcanic Geothermal, Bora, Centre of Sulawesi
Full text linkThe existence of geological structures is one of the important parameters in determining the permeability zone in a geothermal system. This research was conducted in a non-volcanic geothermal field, Bora, located in the province of Central Sulawesi, aiming to identify the subsurface features, especially geological structures related to permeability zones by optimizing geophysical data. Magnetotelluric (MT) 3D inversion modelling is some of the latest methods to identify geological structural patterns in geothermal systems. The results of the MT model and analysis its parameters can find variations in the distribution of subsurface resistivity, orientation of the direction of the prospect area, and indications of geological structure zones. The type and geometry of the geological structure associated with the high permeability zone can be complemented by determining the contrast of gravity values and analysis of the maximum First Horizontal Derivative (FHD) and zero of the Second Vertical Derivative (SVD). Based on the analysis of geophysical data, it is possible to identify the permeability zone associated with the main structure, namely the Palu-Koro fault, delineate the geothermal reservoir at a depth of 1500-2000 meters and determine the location of well drilling. To visualize the geothermal system comprehensively, a conceptual model is developed by integrating the geophysical model with geological and geochemical data that are correlated with each other, therefore it can assist in determining the location of production well development