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.
Gupta, M K (Oil and Natural Gas Corporation Ltd) | Sukanandan, J N (Oil and Natural Gas Corporation Ltd) | Singh, V K (Oil and Natural Gas Corporation Ltd) | Pawar, A S (Oil and Natural Gas Corporation Ltd) | Deuri, BUDHIN (Oil and Natural Gas Corporation Ltd)
In an offshore field, mitigation of H2S from natural gas itself is a big challenge. A situation where high H2S present in well fluid increases the challenges several fold to sweet both processed oil and gas. In a wellhead platform/remote location where manual intervention requirement is minimal, conventional process has several limitation such as space availability, load on structure, frequent monitoring etc., hence may not be suitable for mitigation of H2S from processed gas and oil.
In this work, an approach is adopted for sweetening of sour gas and sour crude in an optimum way, keeping offshore constraints in mind and without usage of rotating equipment's. An integrated simulation model is developed in Aspen HYSYS process simulator wherein well fluid from well manifold is processed in three phase oil and gas separator. The gas liberated from the separator is first sweetened in adsorption columns considering three bed systems unlike general usage of two. The oil is sweetened in an envisaged stripper column utilizing sweet gas from adsorption column as stripping gas. In this work, a three bed adsorption column is envisaged wherein 1st two column in used for sweetening of gas liberated from separator which consists of around 7500ppm H2S. Sour oil from the separator which contains around 2000 ppm of dissolved H2S is processed in a stripper column for mitigation of H2S dissolved in the oil. Sweet gas liberated from 1st two column of adsorber bed is used as stripping gas for oil sweetening. H2S liberated from stripper column is routed to the 3rd column for sweetening. After this gas from all the adsorber column is combined and routed to process platform along with the sweet oil. Analysis reveals that, this scheme can sweeten altogether both oil and gas to the desired H2S level without the need of any rotating equipment's and must be a suitable for remote location.
A holistic approach was taken for sweetening of oil and gas without the need of any rotating equipment's, & any chemicals, unlike the conventional method and hence can be suitably adopted for an offshore environment or at remote location where requirement of manual intervention is bare minimum.
Foaming in absorber column for sour gas treatment using amine is a common problem which adversely affects column performance leading to reduction in sales and fuel-gas production and solvent loss. Mostly antifoam injection has been a common method to counter the foaming, large dosage and frequent dosing of antifoam many a times aggravates the problem. This study details an alternative technique based on pressure pulse mechanism to control foaming in one of ONGC's gas sweetening plants.
One of ONGC's amine based sour gas sweetening plants faced severe foaming problem frequently. The feed rate is 200 kscm/hr and absorber column operating pressure is 51 kg/cm2. The experiment utilizes the property of surface tension which fluctuates with change in pressure of the system leading to foam collapse. The experimental procedure involved varying the sour gas feed rate, thereby creating pressure pulse inside the absorber column. Differential pressure across the column which is an indicator of foaming tendency is then monitored and controlled within 1.0 kg/cm2 and recorded for establishing effectiveness of the method.
It is observed that by providing a number of cycles of pressure pulse in the absorber, the differential pressure stabilizes gradually which indicates collapse of foam. It shows that whenever there is increase in feed, expansion of bubble takes place which provides high interfacial liquid-vapour contact. On the other hand whenever there is decrease in feed rate, compression of bubble takes place which provides low interfacial liquid-vapour contact. Surface layer surrounding the bubbles in a foam acts as a membrane or skin that can stretch or relax in response to change in pressure and gives a mechanical shock which breaks the bubble. The increase of size ultimately leads to instability and break-up of the upper surface and releases the liquid holdup. Hence by using feed rate spikes, the pressure of the bubble is pulsed to higher levels and returned to substantially the original level. This cycle continues for a selected number of times so that this pressure pulse travels through the liquid and bubbles and affects its surface tension. This results into a transition phase which in very high energy level breaks the bubble and releases the gas and decreases the liquid hold up and controls the foaming phenomenon.
This paper will gives an insight into a novel methodology of mitigating foaming problem in a sour gas treating absorber just by varying the feed rates in a controlled manner. This technique eliminates the need for injecting antifoam agents which in turn will reduce the operating expenditure of the plant. Adverse impact on environment due to excessive use of antifoam agent is also minimized.
Drilling operations are faced with conditions of subsurface uncertainty with unexpected drilling hazard potential. Operation is done in 24 hours a day continuously, until drilling is declared complete. The consequence of this work environment is the potential for high work accident, one of which is caused by situational conditions in the field that allow the communication limitations in clear and detailed.
Such conditions may include high-noise working conditions, limited visibility due to weather hazards (rain, fog, dark / night), and sour gas exposure. In this condition, often verbal communication is followed by non verbal communication, either in the form of the use of horns (morse), flag raising (semaphore) and limb movements. Non-verbal communication will be more urgent if the drilling operation conditions in emergency conditions, such as the occurrence of kick, blowout and exposure to sour gases. Non-verbal communication occasionally used in any drilling site does not have standardization, thus increasing the potential for communication errors.
Methods Non-verbal instructions intended in this paper is a sign language that serves as a medium for delivering work orders (instructions). This non verbal instruction uses one limb, represented by at least 2 limb movements in at least 2 stages of movement, to interpret a command or work instruction. If less than 2 movements or less than 1 stage of movement, then the movement of the body may have meaning, but can not be implemented because the instructions are not complete
With the invention, paper and efforts of this standardization, the communication process and the delivery of orders in both normal and emergency conditions at the drilling sites can be carried out in a structured, standardized, clear, detailed and widely applicable manner. The instruction method in the form of non-verbal codes is named: NS Blind Code Drilling, which has been registered since December 2014 to the Directorate General of Intellectual Property Rights and is in process related to the patent application.
Upstream Oil & Gas Industry has witnessed improved HSE performance over time, by adopting latest technology and standards, engineering improvements, including hardware and adopting new processes and systems with maximum emphasis on safety with very good management systems. Compliance and audits have also improved a lot. However, improvement in culture, behavior and commitment at all levels are very important to deliver better business value in Personal and process safety.
Global energy risk engineering companies collate accident data over years and it is very clear that accidents continue to happen, which forces us to think methodology to improve personnel and process safety aspects continuously. It is observed that we are poor in assessing risk as we become used to risk, which could be due to over confidence, ignorance and safety culture issues. As per IOGP Incident Statistics, upstream process has improved over years, while we need to further improve in drilling operations.
It has been seen that Oil & Gas drilling industry is implementing personnel safety very rigorously with greater awareness, certified training programs, advanced technology, mock drills etc. However, Process safety in drilling industry needs greater emphasis. Some of the processes i.e. safety case, Risk and Control register with risk identification, assessment, response, financial impact, control, remediation and self-verification needs to be pursued rigorously. Processes and systems with organizational structure, quality of engineering decisions and understanding safety risk Vs commercial risk and suitable mitigation measures need to be pursued further. Decision hazards are very important to be analyzed including the process and lessons learnt. In addition to above, the basics of safety and the culture of caring for self, colleagues and the Assets are very important aspects.
This paper discusses the culture, processes and systems for safe operations in the upstream industry with special reference to drilling and completion operations.
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.