Multiphase Pump Systems: A Cost-Effective Surface Solution For EOR
Roberto Mantini, Well Production Services Director, Bonatti S.p.A.
The recent trends in the Oil &Gas market have demonstrated that the combination of the natural depletion of mature reservoirs with the volatility of oil price is forcing IOC, NOC, and small independent producer to rearrange the mix of investment towards larger projects targeting shorter returns and cost efficiency. In parallel, the existing reservoirs, are “squeezed” as much as possible taking advantage of the already-in-place infrastructure using the new technologies for the enhanced oil recovery.
In the last fifteen years, Bonatti—integral oil & gas solution provider for the upstream sector—embraced the new challenge of enhancing oil & gas recovery solutions, applying its own surface technologies to depleting wells through its “Well Production Services” (WPS) Business line. Bonatti proposes an innovative “full rental Solution” able to increase production of marginal fields, without being Capital intensive for the Operators.
Within its Service Portfolio, the most advanced and technological one is the Multi-phase Pumping Service. This Service solution is based on multiphase pumping systems able to treat multiphase fluids (oil, gas, condensate, with presence of water, solids and others minor components) without the need of an early treatment and/or separation. The system basically lowers the well head pressure or boosts the flow of a manifold, allowing the multiphase fluid to reach the CPF.
The advantage in terms of production is to grant additional barrels equivalent to be injected in the network, maximizing wells’ optimization and the overall production life. Others advantages, compared to the classical production systems, are the absence of gas flaring with a significantly lower environmental impact, gas monetization at the treatment plants where separation is commercially possible, and fast truck production startup.
In multiphase flow, the gas volume fraction (GVF) is the volume of gas flow divided by the total volume of fluid flowing. In gas wells, the production must flow through pressurized pipelines, and hence compressors and separators are the standard boosting production method. In contrast, for oil and rich gas wells, multi-phase pumps are used instead. However, the typical application is limited to wells with GVF up to 95%.
Bonatti improved the existing technology in order to sustain production in the hardest applications with GVF up to 100%, where other techniques have previously failed. The company offered a commercial solution to meet Operators’ cash flow objectives. The technology of Multiphase pumps has been improved in order to treat rich & lean gas wells present in Algeria, with high GVF (up to 100%), and through advanced satellite remotization to increase equipment availability in remote areas and decrease operating costs.
Oil operators in addition to quick mobilizations of systems usually require the flexibility to adjust the hydraulics of such plants to adapt the pressures and volumes based on reservoirs variations
Bonatti Well Production Services is offering a “One stop shop” solution with the full responsibility for the engineering, procurement, manufacturing, installation, commissioning, start-up, maintenance and operation of complex multiphase plant system including the power generation, fuels tanks, step-up converter, control rooms and fencing, in the most remote areas.
Bonatti Multiphase Pumping System are directly designed and managed through the full life cycle: from the installation to the operation & maintenance, including warehouse and spare parts management and optimization. Availability of different set of pump-hydraulics allow to adjust differential pressure & volumes, guarantee the possibility to enlarge the operating envelope, follow the operating parameters of the reservoir, and allow a stable production while wells are depleting.
Being the approach on a rental basis, all assets and related spares & consumable and resources involved in the daily O&M are at Bonatti charge, while the service is paid by clients with a fixed “running hour fee”. Oil operators in addition to quick mobilizations of systems usually require the flexibility to adjust the hydraulics of such plants to adapt the pressures and volumes based on reservoirs variations. Bonatti WPS responded by developing pre-engineered set of hydraulics and fully skidded systems to minimize mobilization times, to quickly cope with changing parameters, and guarantee fast response times.
The combined knowledge from multiple disciplines, such as reservoir, production, engineering, construction and O&M, combined with a strong logistics capability, are vital to get proper designs and strategies to ensure the success of multiphase pumps installations. After few years such challenge is won, and Bonatti WPS with 50 plants in operation is producing on behalf of major Oil & Gas companies, more than 150,000 barrels of oil and 8 million standard cubic meters of gas per day. The multiphase technology allows the transport of oil, gas & water from well heads/ clusters of wells, without the need of separation. This helps the commercial viability of hydrocarbons recovery, avoiding gas flaring and allowing gas monetization at the treatment plants, where separation is commercially possible.
In order to have the flexibility to treat both rich and lean gas wells, with a scenario that is evolving in line with reservoir changing parameters, Bonatti is able to select the right multi-phase pump system by comparing different boosting systems performance, and jointly with operators, analyzing the production scenario on well by well basis.
Such surface multiphase system is a very cost-effective solution to enhance oil & gas production compared to other downhole systems, since it does not require any intervention or change to the installed well completion, and upon the fact that it is a surface application, it has small intervention cost and production losses in case any maintenance is required.
The multiphase twin screw pumps being the central part of these complex systems, are customized by Bonatti to allow a wide range of operating conditions. Therefore, it is possible to still operate under the reduction of suction pressure in order to manage production decline and subsequent changes of gas-liquid ratios due to further reservoir depletion. The success of this new pump application relies on the installed liquid management system and its control, capable to monitor, manage and adjust the operating parameters of the pumps in real time, allowing the necessary vibration control, pump priming, and temperature reduction to avoid overheating that will eventually halt the pumps and compromise the final performance.
Such Technology for multiphase pumping systems & rental solutions allow IOC & NOC to produce additional oil & gas from existing depleting wells, reducing flaring, with no capex investments and in a competitive way, freeing up their capital to focus their capex investments on the development of major and more remunerative projects.
This ongoing trend in the oil & gas industry that has been accelerated by 2015 oil price drop, where major oil & gas companies involve suppliers to have more “skin in the game” with more risk sharing. Some oil & gas Service providers such as Bonatti WPS has accepted the challenge acting as partners with a BOO schemes on Multiphase plant systems, with Capex investments on their side in order to transform oil & gas companies’ capital cost in operating costs, lowering project risks, improving project cash flow, flexibility, and paying a “service” rather than buying assets.
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