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Optimal allocation of gas-injection rates in large fields through a gas lift network is a challenging task. Traditional gas lift optimization programs may prove inefficient or incapable of modeling gas lift optimization in extremely large networks. The key objective of the complete paper is to assess the feasibility of using the genetic algorithm (GA) technique to optimize the allocation of continuous gas lift injection rate in a network of a Middle Eastern oil field with 43 gas lift injected wells through numerical modeling and simulation studies. GA is an optimization technique that solves constrained and unconstrained optimization problems through a natural-selection process based on the concept of evolutionary biology, including the fundamental processes of selection, crossover, and mutation. Instead of considering a single point or solution, a population of solutions is designed.
This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 20254, “Numerical Simulation of Gas Lift Optimization Using Genetic Algorithm for a Middle East Oil Field: Feasibility Study,” by Mustafa AlJuboori and Mofazzal Hossain, SPE, Curtin University, and Omar Al-Fatlawi, SPE, University of Baghdad, et al. The paper has not been peer reviewed. Copyright 2021 International Petroleum Technology Conference. Reproduced by permission. Optimal allocation of gas-injection rates in large fields through a gas lift network is a challenging task. Traditional gas lift optimization programs may prove inefficient or incapable of modeling gas lift optimization in extremely large networks. The key objective of the complete paper is to assess the feasibility of using the genetic algorithm (GA) technique to optimize the allocation of continuous gas lift injection rate in a network of a Middle Eastern oil field with 43 gas lift injected wells through numerical modeling and simulation studies. GA GA is an optimization technique that solves constrained and unconstrained optimization problems through a natural-selection process based on the concept of evolutionary biology, including the fundamental processes of selection, crossover, and mutation. Instead of considering a single point or solution, a population of solutions is designed. The algorithm modifies the population of individual solutions repetitively, selects individuals randomly from the current population as parents, and uses these parents to produce the children for the next generation. The population evolves over successive generations toward an optimal solution. The solution process of GA follows different principles as compared with conventional approaches. These fundamental differences are as follows: - GA uses objective function. - Instead of using a single point, it uses a population of design points or variables that avoid a local optimum solution. - Strings of binary numbers represent the design variables, which are similar to chromosomes in genetics, so discrete and integer problems are naturally applicable to GA. GA avoids falling into local optimums by sustaining multiple points to multiple-point approaches of each generation. In such a method, the probability of surviving the best, fittest solution is high as compared with a low-fitness solution. As a result, the GA mostly will result in a global optimal solution. GA techniques consists of five basic phases: - Initial population - Fitness function - Selection - Crossover - Mutation The process begins with an initial population comprising a set of individuals (i.e., solutions) within a search space. An individual is characterized by a range of combinations of the design variables (or parameters) termed “genes,” which are joined into a string to form a chromosome (or solution). For each solution, the objective function is assessed with regard to its level of fitness. Each solution is paired with another to form a mating pair, used for reproduction of subsequent populations. The mating pairs produce new solutions as offspring, which retain values of the design variables generated by crossover of the parents’ values. In addition, random mutation is introduced to some of the new solution’s values. The process of GA technique is random, even though its optimization permits one solution to establish the level of control.
Abstract Over the past 40 years, the oil and gas industry standard for performing wellbore surveys with measurements-while-drilling (MWD) tools was by six-axis stationary surveys. These surveys required a sequence of events involving releasing drillstring torque and pressure and providing zero motion while making and sending downhole survey measurements. This procedure involves drilling risks, delivers reduced drilling efficiency and increases the risk of differential sticking in depleted reservoirs. As a leader in modernizing the drilling industry, a major operator has worked with a major directional service provider to pioneer a new MWD surveying technology that delivers definitive surveys while drilling and without any need for stationary time or the risks associated with it. The breakthrough technology is expected to change the previous 40 years of industry practice with a new MWD surveying technology known as definitive dynamic surveys (DDS) technology. The technology will deliver definitive surveys while on bottom drilling with full parameters and complete data quality control. This technology will have the benefit of eliminating the current time needed for stationary surveys, reducing the differential sticking risks, increasing surveying frequency for better wellbore positions and providing improved wellbore tortuosity understanding to manage microdoglegs for improved wellbore quality and completion operations integrity. As a main field tester of this technology, over 30 test runs were made within Middle East fields. As the technology matured, three operational runs have been recently conducted with the aim of comparing and qualifying them compared to industry standard gyro and MWD surveys. The operations were conducted in different well profiles including a vertical, a highly deviated, and a horizontal well. The results have shown an excellent match with less than 0.3° in inclination and 0.5° in azimuth and well within the bounds of their respective error models. The data also showed the improvement in well positioning and drilling efficiency using this technology. Finally, the technology has shown around 50% reduction in connection time on the trial wells. These results have given the required confidence for the technology, gaining the benefits this disruptive technology brings to the drilling process. This technology is expected to change the industry norm of wellbore surveying and produce a disruptive change in the drilling and well placement operations.
Al-Janabi, Mohammed Ahmed (Missan Oil Company) | Al-Fatlawi, Omar F. (University of Baghdad) | Sadiq, Dhifaf J. (University of Baghdad) | Mahmood, Haider Abdulmuhsin (Basrah Oil Company) | Al-Juboori, Mustafa Alaulddin (Iraqi Drilling Company)
Abstract Artificial lift techniques are a highly effective solution to aid the deterioration of the production especially for mature oil fields, gas lift is one of the oldest and most applied artificial lift methods especially for large oil fields, the gas that is required for injection is quite scarce and expensive resource, optimally allocating the injection rate in each well is a high importance task and not easily applicable. Conventional methods faced some major problems in solving this problem in a network with large number of wells, multi-constrains, multi-objectives, and limited amount of gas. This paper focuses on utilizing the Genetic Algorithm (GA) as a gas lift optimization algorithm to tackle the challenging task of optimally allocating the gas lift injection rate through numerical modeling and simulation studies to maximize the oil production of a Middle Eastern oil field with 20 production wells with limited amount of gas to be injected. The key objective of this study is to assess the performance of the wells of the field after applying gas lift as an artificial lift method and applying the genetic algorithm as an optimization algorithm while comparing the results of the network to the case of artificially lifted wells by utilizing ESP pumps to the network and to have a more accurate view on the practicability of applying the gas lift optimization technique. The comparison is based on different measures and sensitivity studies, reservoir pressure, and water cut sensitivity analysis are applied to allow the assessment of the performance of the wells in the network throughout the life of the field. To have a full and insight view an economic study and comparison was applied in this study to estimate the benefits of applying the gas lift method and the GA optimization technique while comparing the results to the case of the ESP pumps and the case of naturally flowing wells. The gas lift technique proved to have the ability to enhance the production of the oil field and the optimization process showed quite an enhancement in the task of maximizing the oil production rate while using the same amount of gas to be injected in the each well, the sensitivity analysis showed that the gas lift method is comparable to the other artificial lift method and it have an upper hand in handling the reservoir pressure reduction, and economically CAPEX of the gas lift were calculated to be able to assess the time to reach a profitable income by comparing the results of OPEX of gas lift the technique showed a profitable income higher than the cases of naturally flowing wells and the ESP pumps lifted wells. Additionally, the paper illustrated the genetic algorithm (GA) optimization model in a way that allowed it to be followed as a guide for the task of optimizing the gas injection rate for a network with a large number of wells and limited amount of gas to be injected.
Iraq and Total expect to finalize a contract by July to implement one or more dual-energy megaprojects to ramp up gas production, end flaring, and produce electricity from solar energy. Iraq's oil minister, Ihsan Abdul Jabbar, gave an update on the negotiations with Total in an interview 27 March with the Arabic-language news outlet, AsharqNews. The US is pressuring Iraq to produce more gas to reduce its dependence on Iran for gas and electricity imports. Iraq has received waivers to continue to import Iranian energy since the US imposed sanctions on Tehran in 2018, but these waivers are temporary. Iraq's problem is that most of the gas it produces is associated gas from produced oil, and that associated gas is currently being flared.
Abstract Inflow Control Device (ICD) completions have been used widely in the energy industry to balance the inflow of produced fluids, while delaying water breakthrough. Improving the reservoir drainage results in higher oil recovery. Traditional completions are typically deployed with washpipe to provide washdown and circulation capability. This is especially advantageous for Run In Hole (RIH) through tight spots and extended-reach wells. A tailored ICD design with dissolvable materials was tested and optimized for Middle Eastern fields with the first successful installation in UAE of a washpipe-free ICD completion. The washpipe-free adjustable ICD completion utilizes a combination of permanent and dissolvable temporary ICD plugs. A range of dissolving materials were developed and tested in a variety of representative downhole conditions, including temperature and pressure variables. The dissolvable materials were tailored specifically to suit the fluid program and fluid additives, common to the Middle East. Multiple plug designs were subjected to small-scale and full-scale tests. Computational Fluid Dynamics (CFD) simulations evolved the design of the ICD housing to ensure that the dissolution fluid would reach the ICD plugs. The dissolution rates of the dissolvable materials were empirically established at representative downhole temperatures with field fluid samples. The degradation and pressure integrity of the materials was validated in small- and full-scale testing. Through full-scale testing, the operational sequences during RIH including displacement and filter cake breaker spotting were replicated with representative pressures, fluid rates, bottom hole temperatures (BHT), and fluid compositions used in the Middle East field. The validated ICD plugging rod technology was successfully run in the UAE in an extended-reach horizontal well. The permanent plugs allowed for customization of the completion inflow profile as per the most recent logs, while the dissolvable temporary plugs provided a completion string with pressure integrity while running in hole - capable of washdown, circulation, and filter cake treatment placement. After installation, the temporary plugs dissolved, opening the completion to production through the ICDs for improved reservoir management. The ICD with dissolvable technology allowed deployment of the completion successfully to target depth (TD) with the pressure integrity required for the displacement operations. In not running and retrieving an inner string, and achieving wellbore displacement at a faster rate, time savings for the 6000 ft OH completion were estimated between 35-50 hours, with an estimated cost saving of a half-million dollars.
Sabahi, Atiya (Petroleum Development Oman) | Rahbi, Said (Petroleum Development Oman) | Harthi, Mahmood (Petroleum Development Oman) | Choudhury, Suryyendu (Petroleum Development Oman) | Darmaki, Faisal (Petroleum Development Oman) | Lawati, Ali (Petroleum Development Oman) | Ghatrifi, Suhaib (Petroleum Development Oman) | Mahrouqi, Iman (Petroleum Development Oman) | Morianta, Marpaung (Petroleum Development Oman) | Abri, Yaqoob (Petroleum Development Oman) | Al-Jumah, Ali (Petroleum Development Oman)
Abstract The objective of this study is to evaluate and de-risk the extension of the Kahmah Group, which is a newly identified carbonate extension in the Eastern part of XX field, and to assess and unlock further appraisal and development opportunities. Eastern field correlation was done by correlating the wells that has encountered Kahmah carbonate, the ones showing low Gamma Ray (GR) traces. Well correlation was done mainly on Petrophysical properties of three vertical penetrations that show distinct and abrupt change from high GR (Base Nahr Umr Shale and/or Mahwis sandstones) to low GR reflecting Kahmah carbonates. Based on the thicknesses of Kahmah based on the vertical well data and commercial oil seen in all wells in the vicinity, thickness and expected oil distribution maps were created. The main findings from the correlation are: 1) Kahmah reservoir is divided into two pays and two non-pays zones as seen in XX-1H1. 2) The reservoir is thickest around XX-1 and thins out toward YY-10 to the south and disappears completely in XX-5 to the north, portraying a wedge- shape. Kahmah reservoir varies in thickness, with thickest interval encountered in XX-1 with 11m. The reservoir thins out towards the edge closer to YY-10 confirming the wedge-like structure. A conceptual understanding has been incorporated in generating cross-sections portraying and proving the wedge-shape structure of Kahmah. Like any other new formation development, many uncertainties are associated with Kahmah development like formation extension, reservoir/fluid properties, pressure behaviour and others. The key observations from this project can be summarized as following: Different packages of reservoir. May be of different or similar properties Extension of Kahmah towards northern part of XX field is still highly uncertain Continuity of Kahmah Reservoir is uncertain Reservoir pressure and communication with Mahwis formation need to be evaluated Reservoir and fluid properties also need to be evaluated
AlJuboori, Mustafa (Curtin University) | Hossain, Mofazzal (Curtin University) | Al-Fatlawi, Omar (University of Baghdad-Department of Petroleum Engineering) | Kabir, Akim (Saudi Aramco) | Radhi, Abbas (Missan Oil Company)
Gas-lift technique plays an important role in sustaining oil production, especially from a mature field when the reservoirs’ natural energy becomes insufficient. However, optimally allocation of the gas injection rate in a large field through its gas-lift network system towards maximization of oil production rate is a challenging task. The conventional gas-lift optimization problems may become inefficient and incapable of modelling the gas-lift optimization in a large network system with problems associated with multi-objective, multi-constrained, and limited gas injection rate. The key objective of this study is to assess the feasibility of utilizing the Genetic Algorithm (GA) technique to optimize the allocation of the continuous gas-lift injection rate in a network system of a Middle Eastern oil field with 43 gas-lift injected wells through numerical modelling and simulation studies. Reservoir pressure and water cut sensitivity studies are performed to investigate the potential impacts of these parameters on well production performance and production life cycle of the field. Sample economics analysis are exercised to broaden the understanding of potential benefit of the implementation gas lift techniques in the field from both technical and economic viewpoint. In addition, while application of GA is not a new idea, this paper elaborates the GA based optimization techniques for improving the oil production rate by implementing gas lift in a large Middle Eastern oil field. The optimization model is presented step by step, so it can easily be followed, and be used as a guide, especially by frontline production engineers involved in designing and development of gas-lift system towards optimally allocation of gas injection rate to individual well in a network system for a field with limited gas injection rate.
Abstract This paper shows how greater scientific rigor in discussions of modelling 3D saturations in the Middle East can lead to better understanding of the reservoirs. It demonstrates with examples how vocabulary limits ability to solve problems related to saturations, compartmentalization, and permeability. It raises the bar on technical discussions of saturation. "Saturation-height modelling", "transition zones", and "Thomeer hyperbolas" are examples of terms that repeatedly confuse discussions of modelling 3D saturations in the Middle East. Vocabulary exposes a lack of scientific rigor, impedes progress, and leads to notable failures. Saturation is not merely a function of height. At the very least, it also depends on porosity, permeability, fluid densities, interfacial tension, and contact angle. Limiting it to height requires adding in all of these other functionalities as afterthoughts rather than incorporating them naturally through dimensional analysis. Most glaringly, it obscures the very useful role that saturations have in constraining permeability modelling and identifying reservoir compartments. "Transition zones" focus on saturation and take emphasis away from relative permeability and fractional flow. Bimodal pore systems (abundant in the Middle East) can have such low relative permeability to water at high saturations that even 70% water saturation can produce dry oil. In such cases, talk of a transition zone is counterproductive as it implies high water production. "Thomeer hyperbolas" reveal biases in how to fit capillary pressure curves. Force-fitting all data with a single model is inadequate. It takes emphasis away from understanding pore systems of rocks in favor of promoting a single-minded view. These examples and their implications are discussed in detail. The existing literature is replete with incomplete explanations and misunderstandings that lead to notable failures in modelling Middle Eastern fields. Understandings predicated on simplified descriptions of homogeneous reservoirs are no longer sustainable. A more scientifically rigorous methodology is presented.
Rachapudi, Ramarao Venata (ADNOC ONSHORE) | Alshehhi, Shamma (ADNOC ONSHORE) | Saadwai, Omar (ADNOC ONSHORE) | Ayidinoglu, Gokhan (ADNOC ONSHORE) | Dodan, Cornel (ADNOC ONSHORE) | Khaled, Moutaz Faysal (ADNOC ONSHORE) | Quintero, Fernando (ADNOC ONSHORE) | Mubarak, Saber (ADNOC ONSHORE) | Gali, Appala Raju (ADNOC ONSHORE) | Mohammed, Samy (ADNOC ONSHORE) | Ikogho, Brume (Schlumberger Oil field Services)
Abstract Effective reservoir management is critical to the success of water flood developments. Continuous monitoring of downhole parameters such as pressure, temperature and flow profile in water injector wells is vital in order to optimize the water-flood sweep efficiency and to avoid early water breakthrough in nearby oil producer wells. The target field has three stacked tight carbonate reservoirs with low reservoir energy and as such is being developed with water injection scheme from day one. As such, effective monitoring of downhole injection parameters is important from an early stage. A common industry practice to monitor these parameters is to install Permanent Downhole Gauge (PDHG) and Distributed Temperature Sensing (DTS) system. Recently, a new smart Hybrid Technology has been developed to measure the downhole data at surface. This paper describes the successful application of this hybrid technology in a green onshore oil field development. Details are presented about the well bore segmentation design of the DTS system, the hybrid cable installation and the operational challenges with the hookup to the wellhead control system. The paper also presents the data acquired during commissioning job, and interpretation of the temperature data which was used to generate the injection profile along the wellbore. Finally, a strategy for future implementation of the DTS system is discussed. Overall, this technology showcases the application of the smart hybrid completion for real-time monitoring of the water injection profile, including the pressure and rates along with injection volume per segment in the horizontal section. Real-time data from the hybrid technology has been integrated to digital oil field implementation to enhance the real time decision making to optimize the injection rates and to allow the operator to implement the decisions without any delay. This technology optimized the cables requirement and maximized the utilization of cable for multi-application environment to support acquiring Pressure, DTS and DAS data to generate real time injection profile.