Oil production decline and excessive water production are prevalent in mature fields and unconventional plays, which significantly impact the profitability of the wells and result in costly water treatment and disposal. To seek for a sustainable development of those wells, reducing the operation cost and extending their economic lives, this paper presents a method of synergistic production of hydrocarbon and electricity, which could harvest the unexploited geothermal energy from the produced water and transfer heat to electricity in the wellbore. Such method is cost-effective, since it does not require any surface power plant facility, and it is replicable in numerous wells including both vertical wells and horizontal wells. By simultaneous coproduction of oil and electricity, the value of existing assets could be fully developed, operation cost could be offset, and the economic life of the well could be extended.
This recently proposed method incorporated thermoelectric power generation technology and oil production. In this method, electricity could be produced by thermoelectric generator (TEG) mounted outside of the tubing wall under temperature gradient created by produced fluid and injected fluids. The aim of this paper is to illustrate the economic practicability of oil-electricity coproduction by using thermoelectric technology in oil wells based on previously proposed design. We examined the technical data of high water-cut oil wells in North Dakota and collected required information with respect to performance thermoelectric power generations. Special emphasis was placed on the key parameters related to project economics, such as thermoelectric material, length of TEG and injection rate. Sensitive studies were carried out to characterize the impact of the key parameters on project profits. We showed that by simultaneously production of oil and electricity, $234,480 of additional value could be generated without interfering with oil production.
The proposed method capitalizes on the unexploited value of produced water and generates additional benefits. This study could provide a workflow for oil and gas operators to evaluate an oil-electricity coproduction project and could act as a guidance to perform and commercialize such project to balance parts of the operation cost and extend the life of the existing assets.
As the oil and gas industry is moving towards digital oil field, the selection of leak detection system (LDS) has become more crucial. Early detection of leaks not only saves environment from Hazardous hydrocarbons but considerable loss in production is also saved. This paper discusses about both internal and external LDS and its applicability for onshore and offshore fields. This paper will ease the selection process of LDS for green and brown fields of both offshore and onshore installation.
Oil spill is considered as one of the biggest ecological disasters due to the scale of the impact it has, on the ecosystem being affected. Offshore oil spills have proven to be a global concern for marine ecosystem and appropriate measures for their control, prevention and removal of contaminants must be considered as top priority.
This paper entails a detailed study of the various available oil spill clean-up techniques and looks at its advantages and limitations. Further, a grading system for all these methods based on oil type, treatment volume, weather conditions, complexity, water turbulence, time required for results, their environmental impact, cost and efficiency is prepared.
In the case of a spill, oil dispersion behavior acts differently for different kind of fluids on sea water depending on their properties, with the effect of turbulence being one of the critical factors. This paper also focuses on the study of different behavior of crude oil and gasoline on sea water using a commercially available CFD (computational fluid dynamics) tool which utilizes more accurate and relevant mathematical formulations. A multiphase oil spill model has been developed to simulate dispersion of oil spill. A consistent Eulerian approach and Navier-Stokes equations is applied across the model, and the diffusion is employed to simulate oil dynamics in the water. The used Multiphase Oil Spill Model takes advantage of recent developments in the areas of CFD.
Paddy cultivation contributes 12% of the total methane emitted in the environment by various sources. At EOGEPL, Systematic Rice Intensification (SRI) has been introduced among the paddy farmers which not only increased their crops’ yield but also controlled the emission of methane directly into atmosphere.
CBM Development requires numerous parcels of land. The farmers who were apprehensive about selling land for the CBM project, or those who were trying to get rid of their land as farming did not seem a good enough source of income, were targeted for this project. Training on the SRI method was conducted along with education on the benefits of the system from a farmer's perspective. In addition, the beneficiaries were given support in the form of seeds, rudimentary machinery and SOS medicines, required for the paddy farming.
The result was awakening for the farmers. In comparison to the traditional method the yield of paddy increased from minimum 37% to maximum 83%, resulting in an increase net income of the farming community. The success factor for EOGEPL, was that by working with 37 farmers on total land area of 4.99 hectare, 45.37 tons of methane emission was controlled. It could be concluded from this project that, the SRI method has the capacity to address 3 major aspects of the modern day. At a time when due to increase of population per head availability of food grain is decreasing, SRI method can double the yield on the same area available. In addition, with decrease in required inputs i.e. the investment and growth of marketable output i.e. yield, the net income of the farmer increases. Most importantly, the practice of SRI controls methane emission which is responsible for greenhouse effect.
The additive information in this paper is that, a single move of SRI practice can address very important problems associated with a CBM-Project and can contribute to the nationwide movement of developing a clean environment and increasing the availability of food grain for the future with increase income to farmers.
Kumar, Ajay (GNPOC Sudan, ONGC Videsh Ltd) | Ibrahim, Yasir (GNPOC Sudan) | Atta, Badrelddin (GNPOC Sudan) | Singh, Vijendra (ONGC Videsh Limited) | Musa Elmubarak, Omer (GNPOC Sudan) | Razak, Chik Adnan Abdul (GNPOC Sudan) | Tripathi, Bamdeo (ONGC Videsh Limited) | Vidyasagar, V. (ONGC Videsh Limited)
Produced water is an inextricable part of the hydrocarbon recovery processes. Safe and environmentally benign disposal of produced water is a major concern for all the oil fields across the world in the present low cost and stringent environmental & statutory compliance era. Many technology available in the market to treat produced water oil contaminants but economical treatment of heavy metal content is still a great challenges for oil industries for safe disposal.
Therefore, New innovative technology i.e. Reed bed technology has been adopted in Heglig field of Sudan to treat the produced water and heavy metal economically through phytoremediation. After successful implementation in Heglig oil field, it is being implemented in other surrounding oil field also.
It is probably a world largest Phytoremediation/Bio-remediation system using Reed Bed technology operating successfully for last 15 years. It is environmental friendly, solar energy driven clean up techniques. This paper not only elucidate, how reed bed removes oil contaminants and heavy metals but also provide clear picture of how this project provide shelter for flora, fauna, other species that help to maintain ecological and environmental balance. Research has also demonstrated that reed-bed technology is feasible and resilient in treating oil produced water
Case studies of mill-out operations in the Permian Basin which evaluate chemical programs and processes used. Results show how existing processes and chemicals used or lack thereof, can affect equipment and undo the preventative chemical treatments used during the hydraulic fracturing process.
The study looks at field water testing performed during various mill-out operations and considered workover rig vs coiled tubing, equipment set up, water & chemicals used, and operational challenges. Water analyses were completed on the injection water and returns at various intervals of the mill-out. Effectiveness of chemical treatment was also monitored when biocide was used.
Field case studies of horizontal wells for two operators in the Permian Basin are presented. Wells were milled-out utilizing workover rigs or coiled tubing units. Testing results show the impact of equipment setup and operations process on the water quality and efficiency of the chemicals used. Water fouling was prevalent in all cases, with coiled tubing jobs showing the highest degree of water contamination and chemical inefficiency. Changes in the water treatment program during operations showed significant improvement and sustainable results. Potential corrosion of the work string due to water fouling and water composition were also observed. The effects of changes to chemical dosages were also monitored. This was important because it identified operational improvements that can reduce equipment replacement costs, reduce chemical overuse and help protect wells from fouling due to high bacteria.
These case study provides a comprehensive review of mill-out operations, which provides guidelines for improving chemical efficiency and potential of extending life of the work string.
Mishra, Gaurav Kumar (Oil and Natural Gas Corporation Limited) | Meena, Rakesh Kumar (Oil and Natural Gas Corporation Limited) | Mitra, Sujit (Oil and Natural Gas Corporation Limited) | Saha, Kunal (Oil and Natural Gas Corporation Limited) | Dhakate, Vilas Pandurangji (Oil and Natural Gas Corporation Limited) | Prakash, Om (Oil and Natural Gas Corporation Limited) | Singh, Raman Kumar (Oil and Natural Gas Corporation Limited)
India is the fastest growing major economy and third largest CO2 emitter in the world. Keeping cognizance of country's energy requirement and commitment to climate change, embarking upon technologies having minimal carbon footprint is the need of the hour. Carbon capture, utilization and storage (CCUS) is one such technology which offers dual benefits of carbon sequestration & enhancing oil production from mature oils fields. This paper outlines ONGC's efforts in bringing nation's first CO2-EOR project.
In view of non-availability of natural CO2 sources in India, usage of anthropogenic CO2 captured from thermal power plants was conceptualised. Based upon CO2 source-sink matching exercise and favourable reservoir & fluid parameters, two oil fields were screened. Technical feasibility of CO2-EOR was first ascertained in laboratory by determination of minimum miscibility pressure (MMP) of CO2 through slim tube experiments. Encouraged by laboratory results, full field compositional simulation studies along with fluid characterization inputs from PVT simulator were carried out.
The MMP were found to be in range 190-250 Ksc, which is below the initial reservoir pressures of the targeted reservoirs. The proposed scheme entails drilling of around 70-80 wells inclusive of both producers & injectors and has the potential to yield an incremental recovery between 10-14 %. A sensitivity analysis based upon purity of CO2 and its adverse effect on MMP was carried out in terms of reduced oil recoveries. Since, this shall be a CCUS project, CO2 from the produced stream has to be separated, compressed and reinjected in a closed loop system. Around 5-8 MMT of CO2 will be sequestrated through Structural, Solubility and Residual trapping mechanisms as modelled in compositional simulator. IFT reduction & decrease in Sor (Residual oil saturation) as result of swelling, miscibility of CO2 with native oil were also modelled in simulator. Being first of its kind project in India, there are many inherent challenges to the CCUS project. At the source end, capturing CO2 from flue gas stream and its compression & transportation is a cost and energy intensive process. At the Sink end, CO2 being acidic and corrosive gas will need retrofit modifications in terms of special corrosion resistant metallurgy for existing processing facilities.
The learning curve from this endeavour shall create knowledge base to further expand deployment of CCUS in India, bringing a large portfolio of reservoirs under the ambit of CO2-EOR. Success of CCUS in India will not only increase domestic oil production but also cater to address the National INDC of reducing emission intensity of GDP by 33-35 percent by 2030 as per Paris agreement.
Hazra, Suchandra (Dynachem Research Center) | Madrid, Vanessa (Dynachem Research Center) | Luzan, Tatiana (Dynachem Research Center) | Van Domelen, Mark (Downhole Chemical Solutions) | Copeland, Chase (Downhole Chemical Solutions)
This paper provides a detailed evaluation of the impact that field source water chemistry has on the performance of friction reducers being used for hydraulic fracturing. In this research, correlations are established between friction reducer performance and source water chemical composition, allowing operators to shorten the learning curve within their fracturing operations, use the most appropriate fluid systems, and potentially mitigate job failures. Extensive testing has been conducted to evaluate friction reducer performance in the presence of different ionic components such as calcium, magnesium, iron and chloride. Performance testing was determined by varying individual ions, as well as using source waters from multiple field locations having total dissolved solid (TDS) levels of well over 100,000 ppm. Testing parameters included friction reduction, hydration rate via viscosity, and rheological characterization for viscosifying-type friction reducers. Principal component analysis was used as statistical tool to characterize the variation in water chemistry and to establish its relationship with friction reducer performance.
Operators in unconventional shales are continuously looking for ways to reduce potential emissions from production facilities. This is especially challenging in liquid-rich regions, such as the Marcellus Shale. As regulations and various industry best practices evolve, facility designs and equipment must evolve as well. Facility-design improvements and successful operational procedures were examined to eliminate or significantly reduce emissions (Porter et al. 2016).
By taking a proactive approach, operators can significantly reduce emissions. In a previous work (Porter et al. 2016), we discussed the key elements of a successful program: (1) a facility design and operational philosophy that considers emission controls, (2) a comprehensive maintenance program that addresses all unplanned or unintended releases encountered during optical-gas-imaging inspections and allows for feedback to facilitate corrective action, and (3) a focused plan for improving technology to diminish the quantity of future leaks. Applying enhanced technology and past experiences to older designs is often the most efficient measure for reducing potential emissions. While these elements are crucial, equally important is the historical defining and tracking of actual identified leaks and the documentation of corrective actions that were taken (Porter et al. 2016). This work further corroborates these key elements.
Additional facility designs for maximum emissions reduction were compared to facility designs in our previous work (Porter et al. 2016), using calculated emissions for each scenario. As well production increases (owing to longer lateral drilling and enhanced stimulation practices), wellsite liquid handling and vapor control become challenging. Techniques for effectively controlling vapors and mitigating emissions were explored in detail, using an actual case study. Also, a previous leak-detection field study with preliminary data was updated with additional years of data, which yielded further clarification of emissions released on a field and pad level with resulting variations in time. Detailed data analysis compiled from inspections identified the most common areas where leaks occur within a production facility—the majority of which were located on atmospheric stock tanks. Data further demonstrated the effectiveness of higher-quality tank relief valves for reducing fugitive leaks.
Production-facility emissions can be managed by using effective production-facility designs and technologies. The present work offers an improved understanding of how technological evolutions can support effective design solutions and processes in a modern shale-gas development (Porter et al. 2016).
A so-called perturb-and-observe (P&O) algorithm is adapted for a novel centrifugal pump to continuously optimize the point of operation. The novel pump coalesces and increases the size of oil droplets in the produced water, resulting in a unique relationship between the coalescing effect and the point of operation, and allowing for the successful implementation of the P&O algorithm. The algorithm was implemented in two different setups, one measuring the dropletsize distribution between the hydrocyclone and the pump, and the other measuring the oil concentration downstream of the hydrocyclone. The latter was considered the most robust because it required no prior knowledge of the system. Nonetheless, both setups achieved satisfying results and compared favorably with a third setup, where the optimal point of operation was predicted using measurements of the upstream produced-water characteristics. Introduction During oil and gas production, significant amounts of water are often produced along with the hydrocarbon mixture. Coproduced water, usually called produced water, can be a considerable source of pollution because it contains combinations of organic and inorganic materials that can lead to toxicity. Because of this, produced water is cleaned before being discharged into the sea or reinjected into a reservoir (Fakhru'l-Razi et al. 2009). Subsequently, in combination with other treatment technologies, hydrocyclones are often used to remove the remaining dispersed oil from the produced water.