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Exploration wells which are considered unproductive due to the low temperature and the liquid phase cannot be used directly, either flash steam or dry steam. For this reason, it is necessary to make a breakthrough to continue to produce electricity with a binary cycle system, so that cost losses in the exploitation phase can be reduced. For this reason, it is necessary to design a practical small-scale binary cycle unit, by designing the type and dimensions of the heat exchanger, piping network, gas turbine, condenser and foot pump. The selection of the DM-01 well which is an exploration well as a supply of heating fluid is because it has a pressure of 10.5 bar and a temperature of 120°C. at a rate of 5 kg/s. The heating fluid is flowed through a 4.5inch diameter pipe from the wellhead to the heat exchanger at a distance of 100 m to heat the working fluid. The cycle that occurs is that the working fluid from the feed pump goes to the heat exchanger and then flows to the turbine then the condenser and returns to the feed pump. By using a heat exangger plate with a heat transfer area of 350 ft2 so that it can increase the temperature of propane to 266 °F so that all propane becomes gas and drives the gas turbine into electric power. [ABSTRACT FROM AUTHOR]

Stuck pipe in geothermal field is significant issues that can arise during drilling operations. This problem generates a substantial quantity of Non-Productive Time (NPT). Due to the fact that drilling in geothermal targets lost circulation zones, the likelihood of stuck pipe events increases. In numerous geothermal drilling projects, lost circulation events that contribute to stuck pipe events have become the most expensive NPT contributor. Although many observations have been made to develop a Machine Learning-based system for preventing stuck pipe incidents in hydrocarbon drilling operations, only few have been developed with drilling data from geothermal well. In this study, we propose a method to create a stuck pipe predictor using several machine learning algorithms such as Support Vector Machine (SVM), Artificial Neural Network (ANN) and Decision Tree (DT). The research showed that Machine Learning has the potential to help preventing stuck pipe incidents in geothermal drilling operation, even though the environment is different with oil and gas drilling operation. According to findings of this study, the Support Vector Machine Algorithm performed well in predicting stuck pipe, with 89% accuracy and 81% recall. [ABSTRACT FROM AUTHOR]

The article provides information on the prospects of geothermal energy, in particular, its use for heating residential and industrial premises and greenhouses, as well as for generating electricity. The advantages and disadvantages of geothermal energy are shown. Geothermal wells release hazardous gases and minerals that lead to reducing the service life of equipment due to deposits of chemicals, the control of the composition and content of which greatly facilitates the development and search for new sources of mineral raw materials. Suggested a device for monitoring the composition, state and content of hazardous gases emitted by a geothermal well, which greatly facilitates the development and search for new sources of geothermal waters. [ABSTRACT FROM AUTHOR]

Lithium extraction from geothermal brines has recently become a strong interest due to the large volume of lithium resources in over 2000 geothermal wells and hot springs worldwide. This article discusses the adsorption behavior of lithium contained in local geothermal brine water originating from the Ciseeng geothermal field in Bogor Regency, West Java Province of Indonesia, by Amberlite IR-120 Na resin. The lithium uptake and the selectivity of lithium adsorption by Amberlite IR 120 Na resin towards alkaline and alkaline earth elements contained in the geothermal brine samples, the equilibrium behavior, and adsorption kinetics were studied. The experimental results show that lithium adsorption increased by the increase in contact time of brine water and Amberlite IR 120 in 4-day continuous adsorption and reached a maximum level at day-3 to 0.0356 mmol/g Li. Li adsorption decreased after day-3, indicating that the Li adsorption had reached an equilibrium state at day-3. The highest adsorption recovery during 4-day continuous adsorption is exhibited by K, followed by Li, Na, Ca, and Mg. Considering a low adsorption percentage of Li (maximum 36.6%) but still higher than that of Ca, Mg, and Na, the adsorption parameters are still to be improved. Linear fitting of the experimental data on the four different isotherm adsorption models indicated that the lithium adsorption from Ciseeng brine fit mostly with Freundlich and Temkin model with an adsorption capacity of the Amberlite IR 120 of 0.051 mg/g. Based on the linear fitting procedure of the experimental data to four different kinetics models, the lithium adsorption from Ciseeng brine onto Amberlite resin follows the Elovich kinetic model (R2 = 0.986), which indicates the dominant chemisorption mechanism in the lithium adsorption process. [ABSTRACT FROM AUTHOR]

The sulphureous spring of Ponte do Fumo is a small natural source of groundwater, whose use for medicinal purposes in rheumatic and dermatological diseases is very old, losing the beginning of its use in time. In the 70's of the last century, it was still used in very vernacular installations, however today it is totally abandoned. Because this type of special water resource, has a long and extensive geohydraulic circuit, that spring today continues to maintain its small flow and its unique chemical characteristics, which are very evident in the place, not only because of its bad smell of eggs rotten, such as by the biojelly (white cream) that develops next to it. On the other hand, this type of resource, if captured at depth, has the potential to obtain adequate flow to build a health unit, of the medical spa type, as well as allowing geothermal uses, as these waters at depth tend to be hot. It is therefore very important that studies are carried out on site, which would make it possible to lead to such a situation. Thus, in this paper, in an initial part, introduction, we present the importance of sulphureous waters for society, the elementary aspects of its chemical composition and of its geohydraulic models, among others, such as previous references about the Ponte do Fumo sulphureous spring. Next, the methodology of the work is presented. Then, as results, the geomorphological, geological and hydrogeological aspects, the conceptual geohydraulic model of sulphureous water and also the order of magnitude of water flow to be explored from a deep well, are presented. Finally, some final remarks are presented with the main conclusions, pointing out the best area for prospecting and research in order to contribute to a future sulphureous groundwater abstraction. [ABSTRACT FROM AUTHOR]

Volcanic lithology reservoir, commonly encountered in the geothermal reservoir, is one of the harder types to be developed because of its highly varied porosity and permeability caused by the presence of natural fracture. One of the solutions to increase the productivity of this type of reservoir is called hydraulic fracturing. A simulation is conducted to model the hydraulic fracturing job, as well as its economic analysis for well-X which produced oil from the tuff volcanic reservoir. A new approach to designing hydraulic fracture is by using pseudo-three-dimensional (P3D) model. Simulation using the P3D model will give a more realistic fracture geometry compared to 2D model by also analyzing the rock layers above and below the pay zone. A sensitivity analysis is conducted by varying various parameters to achieve optimum NPV. If production sharing contract (PSC) is used, the optimum case can be achieved by using Jordan Unimin 20/40 as the selected proppant with maximum concentration up to 14 PPA, pump rate 12 bpm, and NPV for 5 years at 10% discount rate of US$ 140,370 with fracture length 69.9 feet and benefit-cost ratio (BCR) 2.23. However, if the gross split (GS) economic system is to be used, the optimum case is the original condition without hydraulic fracturing treatment, which gives NPV at 10% discount rate for 5 years of US$ 481,735. [ABSTRACT FROM AUTHOR]

Indonesia is at the junction of three tectonic plates which play a role in forming Indonesia's volcanic mountains. This source of magma from the mountains becomes a source of heat, making Indonesia one of the countries with the largest geothermal reserves in the world. In the midst of the transition from using fossil energy to renewable energy, the development of geothermal fields has increased quite significantly. However, geothermal field locations are usually in remote areas so that conventional equipment commonly used for oil and gas fields cannot be used for exploration and production activities. Slim hole wells are the choice of Sembalun field developers, especially at Well Y. Production has continued to decline in the last two years. The field developers decided to use hydraulic fracturing with cold water injection to increase production. However, it needs to be further analyzed whether the tubular at well Y is able to withstand the load received due to the use of hydraulic fracturing. Therefore, this study focuses on analyzing the ability of slim hole wells to withstand loads due to high temperatures from geothermal reservoirs and loads due to the implementation of hydraulic fracturing, using stress analysis from three main loads such as burst, collapse and tension. This study will ultimately produce recommendations for the use of slim hole wells and solutions for the failure of wells to withstand loads. Based on the calculation results, the reservoir temperature affects the yield strength of the intermediate casing, production casing and liner to 53052.08, 49309.03, and 46177.89 psi. The calculation of the pressure on the tubular without considering the effect of axial pressure is carried out and shows that the tubing is able to withstand the pressure. Meanwhile, with the effect of axial pressure on the burst and collapse rating, the intermediate and production casing are able to withstand the collapse load, but not the burst load. Meanwhile, the liner is not able to withstand burst loads and also collapse. After that, a triaxial pressure analysis is also performed by calculating von mises equivalent. The results show that yielding occurs in all slim hole used. The incapability of Schedule 40 casing to withstand load, bringing up a recommendation to change the grade of casing to M - 65 for intermediate casing and X - 80 for production casing and liner. In addition, modification of production parameters can also be carried out to reduce the rate of geothermal production, so that slim hole wells are able to withstand the pressure received. Sensitivity on Pump Pressure, Fracture Gradient and Wall Thickness Tolerance was conducted to determine which value is allowed to be modified. [ABSTRACT FROM AUTHOR]

JIWAFlow is a cloud computing system-based wellbore modeling application developed by PT AILIMA, it is used to analyze the effect of heat loss that may occur in wellbore on the productivity of the geothermal well. The author has made a simulation by inputting the required data that is consists of Well Trajectory Data, Casing Design, Feedzone Parameter, Operation Conditions, and Auxiliary Heat Loss. This research is based on the data collected from the geothermal Well Y, the simulation of two-phase flow in wellbore carried out after determining the main task (production: full curve), pressure drop correlation method used (Homonegeous), and approach method according to the type of data available (deterministic) in the simulator. The simulation output consists of the Wellbore Profile and Output Curve, where the output of simulation results is generated into the table and visualized through an analysis curve. The simulation was carried out four times with different flowing time parameters (during the completion test) to see the effect of heat loss on productivity. Firstly, there is no heat loss effect as the baseline scenario, secondly with flowing time of 8 hours, then for three days, and finally in 1 week. After four simulations, the data were collected; Massflow vs. Wellhead Pressure results in the output curve table were compared to see and analyze the presence and how significant the effect of heat loss on productivity in wellbore geothermal field Well Y. [ABSTRACT FROM AUTHOR]

X geothermal field which is being developed by PT. PLN (Persero) with the status is still being explored in progress for development. PT PLN (Persero) has drilled 5 exploration wells from 6 planned wells in the X geothermal working area (WKP), at Eastern Indonesia. The five wells are TLU-D1, TLU-01, TLU-B1, TLU-B2 and TLU-C1. From the results of the fifth well it is necessary to evaluate and update the conceptual model which is expected to provide clearer information on the distribution of heat from the existing geothermal system. The problem of the X Geothermal Field is finding the direction of maximum permeability and heat sources and the amount of electrical energy that can be generated. This research has problem limitations in the simulation of geothermal system modeling and the determination of its electrical energy reserves (MWe). The method used in the conceptual review of geothermal system models is modeling using leapfrog software for simulations after the addition of new drilling data. In the modeling the simulation is done by using a 3 Dimension (3D) image to make it easier to interpret the existing geothermal system, so that it will be easier to determine the shape and distribution of the heat source and its reservoir. The results of this modeling simulation were obtained clearly at a depth of -1750m with a shape that resembles a pear that extends and width to the southeast - south of this study. According to the heat distribution pattern, it can be estimated that the outflow is towards the east while the upflow looks to be directed south. [ABSTRACT FROM AUTHOR]

In drilling geothermal exploration wells, sometimes a small capacity is obtained that produces a small amount of electrical energy. In some remote areas, the need for electricity is vital, because the distribution of electricity from the government sometimes does not reach these areas. For this reason, a mini-scale power plant with a capacity of fewer than 10 MWe is needed to meet the needs of electrical energy, especially in these areas. This research tries to make a mini- scale geothermal using two-phase exploration well data with a pressure of 11 bar, the temperature of 180 °C, the mass flow of 100 kg/s, and drought of 23%. In this case study, the optimization of pressure separator flashing was carried out to obtain optimal energy. Based on the calculation results, the optimum separator flashing pressure is obtained at 4 bar where the 7 bar turbine inlet pressure produces 9.96 MWe with a thermal efficiency of 73%. [ABSTRACT FROM AUTHOR]

Drilling is a critical activity in the development of geothermal energy either in exploration or exploitation phases. The drilling operation aims to make the wellbore under the desired target, function, and time by upholding the principles of engineering and safety. There are many challenges and obstacles faced in drilling operations that make drilling time and activities not according to the plan. These technical or non-technical issues may lead to the presence of non-productive time (NPT) and cost overruns. Analysis of drilling time is essential as an evaluation material for better implementation, and also as a consideration for planning to drill the new wells. This paper will analyze the drilling time to identify activities that contribute to non-productive time (NPT) in the drilling operation of well FT and provide prevention and mitigation solutions. Data analyzed were obtained from the daily drilling report (DDR). [ABSTRACT FROM AUTHOR]

A mathematical model of the open geothermal cyclic system consisting of one production well and several injection wells is presented. The production well is supposed to pump hot water from an underground geothermal reservoir. After the use for heating purposes the cooled water is pumped back into the aquifer through the injection wells. The influence of the location of injection wells relative to the producing well on the change in water temperature in the producing well is investigated. The results of numerical calculations showed that the location of injection wells on a given area has a significant effect on the temperature change in the producing well. Several variants of the location of injection wells at which the temperature of the water in the producing well will be maximum are given. [ABSTRACT FROM AUTHOR]

This research analyzes nonproductive time (NPT) in geothermal drilling operations. In geothermal drilling operations, NPT can be caused by several factors, such as decision making factors, operational planning factors, geological factors, and equipment failure factors. This study was conducted in the three wells geothermal project at MKD location in Indonesia. Each operation and activity that causes nonproductive and down time rig will be recorded and counted as NPT. The data then be identified as the cause of NPT in drilling operations whether caused by decision making factors, operational planning factors, geological factors, or caused by failure factors of rig equipment. Analysis in this study used excel and montecarlo, and the results of the analysis get a comparison of the time between operation and NPT, probability of the factors causing NPT and the probability of the risk level of each factor causing nonproductive time. The results of the analysis will be used as a reference in risk mitigation in geothermal well drilling. [ABSTRACT FROM AUTHOR]

A geothermal open loop system consisting of one production well and several injection wells is considered. The production well serves to raise hot water from a geothermal underground reservoir, which can be used for building heating or for other purposes. As a result, the water is cooled and then pumped through injection wells back into the geothermal reservoir. The cooled water begins to be filtered in the reservoir in the direction of the production well. A mathematical model describing the distribution of a cold water front in such a system is presented. A software package has been developed that makes it possible to evaluate the efficiency of the location of injection wells in a geothermal reservoir in order to increase the operating time of such a system, since the operation of the geothermal system life is over as soon as the cold water front reaches the production well. [ABSTRACT FROM AUTHOR]

The difficulties related to open loop geothermal systems using includes, in particular, the fact that there is a reverse injection of the cold water through an injection well into an underground aquifer from which hot water is extracted. This necessity for an injection well presence is caused the thermal water from an underground reservoir possible to be high mineralize and to contain toxic compounds and metals, and in most cases one have to avoid to discharge these waters into ground surface natural water systems. An open loop geothermal system of three wells is considered, which can be both productive and injection wells. The developed algorithms and programs allow to select an optimal system configuration of three wells for a specific geothermal deposit. The results of numerical calculations for various variants of the geothermal system are presented. [ABSTRACT FROM AUTHOR]

Retrofitting depleted oil wells into geothermal wells can potentially solve the main issues in conventional geothermal wells: high capital costs for drilling geothermal wells and high risk of environmental consequences. For this application, the understanding of the temperature change is crucial as it affects the performance of the wellbore heat exchanger and the power generated from this well. Therefore, the current study is focused on the evaluation of oil wellbore's feasibility as a geothermal energy resource via investigating the heat transfer in the wellbore using computational fluid dynamic (CFD) approach based on actual measured thermal parameters of cement specimen. A two-dimensional axis-symmetry model for fluid flow and heat transfer in a wellbore is developed. The properties of the cement casing were obtained experimentally. The effect of downhole temperatures and velocities of the heat transfer fluid (oil) on the heat transfer and temperature distribution is evaluated and discussed in view of numerical results. The results revealed that the downhole velocity and temperature plays an insignificant role in affecting the cement outer wall temperature, justifying that the heat transfer within the wellbore is consistent. This indicates the potential of oil wellbores as sustainable geothermal energy resources. This study serves as a guideline for future researchers to design wellbore heat exchangers from depleted oil wells by highlighting the temperature distribution of the cement outer wall and the effects of downhole velocity and temperature. [ABSTRACT FROM AUTHOR]