Through Collaboration With Shell, Innovative Answers Developed
Baker Hughes customizes pumping solutions to solve development’s challenges.Baker Hughes brought a totally different subsea solution for deepwater applications to Shell’s Parque das Conchas field development by installing electrical submersible pumping (ESP) systems in caisson on the seabed to boost several production wells in commingle with a single unit. Traditionally, ESPs are installed in well bores. The project, located in BC-10 block offshore brazil, encompasses three separate fields – Ostra, Abalone, and Argonauta B-West – each with different challenges. Baker Hughes’ technical capability to develop a fit-for-purpose solution as well as the company’s demonstrated commitment to investment in new technologies resulted in a collaborative approach to solving the development’s challenges with Shell.
Two of the fields in BC-10 – Ostra and Argonauta B-West – which Shell operates in a joint venture with Petrobras and ONGC, are equipped with ESP systems located inside a caisson below the seabed. several production wells can feed the ESP. However, due to different operating philosophies, both fields have different configurations.
“The Ostra field is composed of two connected production manifolds that bring the production from several wells to the artificial lift manifold (ALM),” said Ignacio Martinez, artificial lift and flow assurance Technical Manager for Baker Hughes. “The ALM is 9 km (approximately 5.6 miles) from the floating production storage and offloading [FPSO] unit and contains four caisson electrical submersible pumping systems.”
Each ESP is enclosed in a 32-in. caisson and there is a gas line that connects the four caissons to the FPSO. The gas is separated from the liquid and vented through the gas line to the FPSO. “This configuration, also called a separator caisson, allows the liquid to fall to the bottom of the caisson where it will then be pumped through a flowline by the ESP equipment to the FPSO,” Martinez explained. The ESP operates as a fluid level control dispositive in the caisson. The pressure on the gas line controls the intake pressure on the ESP equipment and that pressure can be adjusted from the FPSO.
Production from Abalone, the third field, is commingled with the Ostra field. Abalone has a low flowrate and high gas/oil ratio.
“That high gas rate allows pressure to be kept on the gas line. without that extra gas from Abalone, there would not be enough gas on the gas line to flow through, complicating operational issues and not making it possible to use the gas line on the separator caisson,” Martinez said.
In the second field, Argonauta B-West, the caisson is also fed with several production wells, but there is no gas separation. The ESP systems are designed to handle more than 40% gas entrained in the fluids. In this case, the intake pressure is controlled by the ESP. “Argonauta B-West with 17 API is a heavier fluid than Ostra at 28 API, which also affects the operational procedures,” he said.
“The objective was to supply an enhanced run life ESP systems based on proven technology to meet both scenarios where rapid gas decompression, temperature cycles, high-power and high-volume ESP systems are compatible with the subsea infrastructure and Shell’s operational philosophy,” Martinez said.
Critical to the Baker Hughes solution was the fact that the ESP systems were planned as an integral component of the entire hardware configuration. “This differs from the approaches where the ESP is considered as a separate item instead of being pre-planned as part of the final configuration,” Martinez said.
Baker Hughes’ dedication to delivering reliable and technically innovative products and services was applied to the full scale of the process, from the initial research and design efforts through describing the application, qualifying the manufacturing, transporting, and installing the solutions through to commissioning and operation of the equipment.
“This project presented unique challenges and demanded innovative approaches to meet Parque das Conchas’ needs,” Martinez noted. “although we have a demonstrated track record in subsea applications, the complexity of this subsea infrastructure and associated procedures for BC-10 called upon many of our resources. Many hours were dedicated to workshops, internal meetings and meetings with Shell’s experts. Testing of new solutions was required for hardware and new procedures were developed to operate and control the ESP equipment. Many of the hardware solutions on the BC-10 ESP equipment are unique.”
Specifically, the motor used for the ESPs in the BC-10 development was designed and manufactured with new high-end technology seals. “Vanguard™ has been proven to enhance reliability when compared with standard motor construction,” said Martinez. “The extreme performance motor with Vanguard technology is a precision design, manufactured to the highest industry standards. The motors are assembled in a specially designated facility under the close scrutiny of design engineers from Centrilift, a Baker Hughes subsidiary.”
The main hardware improvements were made to the seal section and were required because of expected rapid gas decompression during some transient periods of operation. “Baker Hughes developed solutions to hold up to 1,000 psi per minute of gas decompression from 3,000 to 1,000 psi and 350 psi per minute from 1,000 to 300 psi,” he said.
Rapid decompression is detrimental to all elastomers, necessitating evaluation of composition and change to metal configurations. Components, such as the o-rings on the motor and pump and the power cable were evaluated.
“The BC-10 operational procedures are unique and involve a new philosophy of how to operate ESP equipment,” Martinez noted. “Commissioning of the system and startup has been flawless and the system is in continual operation. To date, there is no subsea boosting system that has the high-volume and high boosting pressure capabilities of this Baker Hughes ESP system, which is considered the most cost-effective solution to the type of operations present in the BC-10 development.”
Martinez said the main objective of all the research was to bring the lessons learned to the design stage, thereby reducing the learning curve during the operational phase. “The applied technology and research enhances the run life of the ESP system and, ultimately, will result in a reduction in the number of interventions.”
Early research and development also improved the quality and outcome of a project which is often influenced by the process and relationship between the operator and the contractor. “In many cases, the operator focuses on the ESP as hardware only, neglecting the importance of the process in the conceptual phase of the project,” Martinez noted. “our work with Shell demonstrates the benefits gained with collaborating to solve unique challenges.”
Many Baker Hughes personnel contributed to the success of the project, especially those located in brazil. “The entire system has been installed and operated by brazilian people, demonstrating the expertise available in the region for delivery of this type of high-end project,” said Martinez. “Rui Pessoa, a member of the brazil team, was the dedicated desk engineer located in Houston who committed more than 18 months to project details. other key personnel included Howard Thompson and his team as technical support; Carl Grotzinger and Ben Gould as project managers and bill largess and his team who managed all processing and manufacturing in Claremore, Okla. all advance qualification testing for every piece of the system was performed using the test wells in the Claremore facility. our management dedicated its best resources from the region as well as from headquarters.”
Research and development was used in installations in Claremore for several studies. The most important was the development of a new high viscosity loop to determine pump operating performance and motor temperature profile in high viscosity scenarios. “This was the first time ever that high volume pumps (10,000 b/d to more than 40,000 b/d) were tested under those conditions and the results were exciting – demonstrating that high volume ESP pumps can be much more efficient than expected,” said Martinez.
“This was a dedicated, successful partnership with Shell which led to further improvements in our processes, products and quality of our services,” Martinez noted. “Our collaboration with shell resulted in a mutual understanding of critical interfaces and delivery of innovative solutions.”
DOWNLOAD PDF (168.4 KB)