Technologies Combine To Benefit Offshore, Remote Artificial Lift
Electric submersible pumps (ESPs) are usually the optimal artificial lift option available in terms of cost-efficiency. However, the potential of ESPs in offshore and other remote locations has been constrained by the high costs incumbent with rig deployment, coupled with loss of production and an inability to access the reservoir without pulling the production tubing.
Headquartered in Houston, AccessESP has integrated two practical technologies into a unique solution that solves this offshore problem by simplifying the conveyance of ESPs without the use of a rig. Operators benefit by being able to maximize the value of ESP wells with significantly lower intervention costs, minimal lost production and full bore access to the reservoir.
The AccessESP solution combines two technologies—a permanent magnetic motor (PMM) and a side-pocket wet connect system—into one tubing-mounted permanent completion and a slickline retrieval assembly. With the company’s technology, operators no longer need to consider an ESP as a part of the completion string that must be pulled whenever there is a need to intervene in the well or to replace an ESP component or system.
Client study: West Africa, offshore installation
Following the failure of the conventional ESP, AccessESP was tasked to install an alternatively deployed ESP to reduce future ESP replacement costs and mitigate production changes by using the Access375 system. The customer was uncertain of the reservoir capacity of the well and ESP size after a long shut-in period and therefore needed a cost-effective method to replace the ESP, if needed.
During the commissioning of the initial Access375 system, the productivity of the well was found to be much higher than expected. Consequently, a new system with increased horsepower (hp) was installed. This retrievable ESP system was replaced with slickline in days rather than months with a conventional ESP and rig.
As a result, the new Access375 system achieved the required drawdown and target production rate.
An industry first
AccessESP installed the first rigless ESP conveyance system in Nigeria in the Ukpokiti No. 4 offshore well in January 2014. The installation was performed using AccessESP’s 375 series, 190 hp PMM and wet connector system. The ESP system was deployed through 4.5-inch tubing on conventional .125-inch slickline after installation of the tubing string. The Ukpokiti No. 4 system was deployed via slickline to a depth of 1,978 m (5,900 ft) and took less than 15 hours to install.
As a flexible solution tailored to a company’s specific needs in each region, the AccessESP system offers significantly lower intervention costs, reduces lost production and provides full-bore access to the reservoir by eliminating the need for a workover rig.
Maximizing well performance
ESP pumps are generally never replaced until they fail, meaning that the ESP pump design must cover three or more years of the life of the well. Production rates and composition change significantly over this period; therefore it is necessary for the pump design to have a large operating range. For most of the pump’s life, it will operate in a compromised, rather than optimal, range.
In the AccessESP system, the pump can operate at a higher level of efficiency based on the actual well conditions, as it can be retrieved at any time to be optimized for the current known well conditions while leaving the motor in the well. This gives the operator an optimized pump design with reduced lifting costs, longer pump run life and lower overall hp required for fluid lift.
The degree of flexibility and ease of operation that is now possible with the AccessESP retrievable ESP system has not been previously possible. Slickline retrievable ESP systems are now a commercially viable technology, proven in a range of challenging environments and successfully operating in fields globally. This technology actively increases rates of production and significantly reduces operating costs, capex and cost per barrel for operators in the global ESP market.
Pentair Delivers Produced Water Management Solutions
The oil and gas exploration industry is under intense scrutiny to address mounting water management challenges. Practices such as water reuse, injection and discharge all impinge on economics. An ever-changing regulatory environment combined with demands from the public sector for conservation and sustainability has put water management at the forefront of the industry.
Produced water streams must be treated prior to disposal, reinjection or reuse. Conventional treatment schemes employ numerous technologies and still achieve inconsistent results. Continually changing inlet conditions often limit their effectiveness. Additionally, conventional systems often call for a heavy dose of chemicals, creating an ongoing economic and chemical management burden for the industry.
Some of the issues that offshore owners and operators are facing include plugging of injection wells and producing formations by solid particles and suspended oil droplets; plugging of lines, valves and orifices due to deposition of inorganic scales; exceeding discharged oil concentrations; and growth of bacteria that plug lines and valves or result in the formation of harmful products.
Effective hydrocarbon recovery and solids removal from produced water streams is critical. Delivering reliable, stable operations enhances performance while addressing the health and safety of the surrounding environment.
Pentair’s Hydrocarbon Recovery Technology (HRT) provides the potential for dramatically improved solids control and hydrocarbon recovery. HRT was designed and engineered to remove solids as fine as a half micron with efficiencies up to 99.98%. Customers using HRT on produced water systems have experienced operational, environmental and economic benefits. Better operational flexibility, savings on chemical additives, lower maintenance costs associated with fouling and elimination of water quality excursions all significantly increase performance.
“HRT has the flexibility to respond to changing produced water conditions as well operations and production conditions fluctuate,” said Pentair’s Dr. Carl Hahn.
The robust design is modular and scalable, suited for either new capital projects or existing equipment upgrades. HRT has demonstrated recovery efficiencies greater than 99.98% with hydrocarbon concentrations up to 5%. This allows effective separation of hydrocarbons as heavy as API gravity 13 oils. This translates into increased throughput, reduced operating costs, more recoverable product and less downtime.
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