The development of a fully electric subsea blowout preventer significantly improves BOP reliability and performance while reducing weight, wellhead fatigue, emergency disconnect times and OPEX. The full-scale testing of electric shear ram actuators on an 18¾-in BOP at HMH’s electrification lab validates the achievement of such benefits.
BRIAN PICCOLO, VIJAY CHATUFALE, SHAH SAKHAWAT and RUNE SAUA, HMH
Over the history of deepwater drilling, the development of hydraulic BOP (blowout preventer) technology has yielded large, heavy and complicated assemblies to be routinely prepared for drilling operations. The current weight, size and complexity of modern BOP stacks have created opportunities to address wellhead fatigue concerns and reduce the substantial amount of time spent on API STD 53 testing, during the well construction process.
However, the current hydraulic control system also reduces peak shearing force with increasing seawater depth, as well as it limits improvements in emergency disconnect times, when considering the time required to shear. To resolve these challenges, BOP experts agree that an alternative to the current hydraulic control system is needed.
To this end, HMH engineers are aggressively developing a fully electric SSBOP (subsea blowout preventer), as shown in Fig. 1, that involves the complete removal of all hydraulics. The article will discuss how a fully electrified control system enables a step change in expectations on BOP reliability, performance and weight.
As part of its comprehensive SSBOP stack electrification initiative, HMH has prioritized the development and testing of a full-scale prototype shear ram actuator. The decision to begin with the shear ram actuator is based on its critical safety role within the stack, as well as the significant complexity it presents in terms of required force and shock loading.
To date, the implementation of the electrified control system has demonstrated significant progress and capabilities, including:
Shearing drill pipe in 12 sec on an 18¾-in BOP—approximately four times faster than the API requirement, as shown in Fig. 2.
Executing drill pipe shears entirely, using stored battery energy.
Achieving high-precision control of the rams (within 0.1 mm), which enables features that reduce critical path test time and reduce wear on elastomers.
Manufacturing is commencing for a full-scale, field-configured version of the shear ram actuators, with testing scheduled for December 2025.
BENEFITS OF AN ELECTRIFIED SUBSEA BOP
While hydraulic BOPs have enabled the execution of many challenging projects, this same technology inhibits oil and gas operators and rig contractors from unlocking a significant amount of value.
Critical path time savings. To begin, conversion to an electric BOP can enable an operator to save $22 million per year in OPEX, per floating rig in the Gulf of Mexico, by reducing the time spent on critical path testing. Completing projects in less time also can reduce carbon footprint. The opportunities for time savings are discussed below.
Prior to the deployment of an SSBOP stack, a required hydraulic pressure test program must be executed with mandatory hold periods. This entire program can be replaced with an electrical continuity check, which can ascertain the integrity of the electric control system almost instantaneously.
Existing BOPs require drilling to stop for weekly function testing, because pressurizing hydraulic BOP actuators results in the wellbore being obstructed. However, with an electric BOP, high-precision control is used to extend and retract each BOP function just a fraction of an inch, without ever encroaching on the wellbore. This feature is referred to as micro-testing. Under such circumstances, each BOP function can be tested in parallel to drilling ahead, resulting in the elimination of lost critical path time. Furthermore, micro-testing substantially reduces unnecessary wear on elastomer wellbore seals, which are not intended to be tested during a weekly function test.
The implementation of an electric control system creates an opportunity to update the industry’s pressure testing policies to reflect the implementation of modern technology. Under such conditions, there is an opportunity to extend pressure test intervals to a period longer than the generally accepted 21 days. The justification for this extension is based on the fact that electric control systems are inherently simpler in nature, compared to their hydraulic counterparts, while being comprised of components with statistically higher reliability ratings.
Furthermore, the implementation of micro-testing and the ability to perform electrical continuity checks substantially reduces wear on elastomers, thereby improving confidence in the technology. Finally, there is an increase in data, which can be used to enhance real-time condition monitoring programs.
One should also note that the spares management and maintenance effort becomes simplified for the rig contractor, due to the reduced number of spare parts and reliability improvements associated with an electric control system. Furthermore, the need for hydraulic BOP fluid is eliminated altogether.
Weight/space savings reduce operational risks, create opportunities for lighter vessels. As shown in Fig. 3, there is a substantial amount of space savings associated with the removal of hydraulics-related skids at surface, in addition to the extensive weight savings associated with the removal of the subsea hydraulic control system. These weight savings translate into a reduction in wellhead fatigue. During the next new build cycle, these weight and space savings can also contribute to more efficiently designed vessels.
Using alternative configurations for BOP stacks, such as a P&A stack, also results in a substantial weight reduction. In doing so, the operational risks associated with P&A operations on older wellheads are reduced, while opportunities are created for lighter vessels to perform the same work. Finally, while this article is focused on deep water, one should also consider the logistical effort saved on land rigs when moving BOP technology from well to well.
Significant improvements in operational performance. The opportunity to drill wells more efficiently and shear at higher peak forces, while reducing EDS time and wellhead fatigue risks, results in a fleet that offers a higher value proposition to the operator, while also being able to compete for a broader range of projects.
The ability to shear in 12 sec enables a 50% reduction in EDS time, assuming accepted sequences in drilling operations today. Such a benefit allows the well to be secured more quickly and enables floating rigs to compete for contracts in shallower water. The increase in shearing speed is primarily the result of the considerable amount of horsepower that can be generated in the space envelope of a BOP operator with an electrical system.
The elimination of subsea accumulator bottles results in a system that is no longer seawater depth-dependent, with regards to its shear force. Instead, the electric BOP system is powered by batteries, drives and an electric motor, which deliver the same peak shear force, regardless of seawater depth. Furthermore, an electric system can deliver the rated peak shearing force continuously and repeatedly.
Finally, battery energy storage systems are more energy-dense than hydraulic accumulators. As a result, stored energy requirements from API and NORSOK can be achieved in just a fraction of the space occupied by subsea accumulator bottles today. Furthermore, the batteries selected to perform this function are capable of high discharge rates and are comprised of a chemistry that is not prone to thermal runaway. The selected battery chemistry is also not flammable.
THE ELECTRIC BOP TECHNOLOGY DEVELOPMENT PROGRAM
The electric BOP program is built on a foundation of proven components from both the oil and gas industry and parallel, rugged industries, where necessary.
Using the shear rams as an example, the wetted wellbore components—such as the BOP body, elastomer seals and cutting technology—remain entirely the same. Key components of the surface and subsea control system also remain the same. However, the existing subsea PLCs are now mapped to an electrical actuation system, as opposed to a MUX pod, accumulators and hydraulic actuators.
The electrical actuation system is comprised of a compact, power-dense motor and a drive system from the transportation industry and a drivetrain from the mining industry, which has equivalent force and shock loading conditions. The battery technology has been acquired from the large data center industry, where high-energy storage density and discharge rates are critical.
To optimize the sizing and selection of key components, as well as validate algorithms, HMH constructed an electrification test rig in Houston, Texas. This test rig was comprised of an 18¾-in, 15K BOP, electro-mechanical actuators, drives and a battery energy storage system. The test rig, as shown in Fig. 4, was designed in a rapid fashion from off-the-shelf components, to enable the development team to quickly validate assumptions throughout the development program. With the test rig assembled, the team was able to perform shearing in 12 sec, micro-testing and soft stopping the shear rams, to reduce wear. The electrification lab will be used for the electrification of other key components on the SSBOP.
With lessons learned from the electrification lab in hand, HMH has been able to swiftly progress into the manufacturing phase for a set of full-scale, field-configured actuators with high confidence, Fig. 5.
The full-scale, field-configured actuators (Fig. 5) are equivalent to the existing 22-in., 5K operators, in terms of their space envelope and peak shear force. However, these electric actuators come with several additional advantages. First, the electric actuator is able to maintain its peak shearing performance through an entire shear and for subsequent shears, due to the elimination of accumulator bottles. Such performance is no longer impacted by seawater depth. Secondly, the system shears in 12 sec, while maintaining the capability to execute the complete API STD 53 test program. Finally, these actuators are designed with a redundant mechanical locking solution and multiple provisions that enable the system to withstand high shock loads. The compactness of these actuators is such that the bonnet doors can still be swung open to perform typical BOP maintenance, as is done today. HMH plans to test these actuators in December 2025.
CONCLUSION
The capabilities unlocked during HMH’s electrification journey have significantly changed performance and reliability expectations for a subsea BOP. The more reliable electric control system—combined with opportunities to reduce EDS time, wellhead fatigue and critical path testing time—ultimately improves safety, reduces OPEX for the operator and enhances the value of a rig contractor’s fleet. Capitalizing on the success of the program thus far, HMH is progressing with the development of the remainder of the major SSBOP components, such as the annular and wellhead/LMRP connector and later, the choke and kill valves and stabs. WO
ACKNOWLEDGMENT
This article is derived from the presentation, “Full scale BOP electrification test rig validates E-BOP benefits,” presented by Brian Piccolo, HMH, at World Oil’s/Gulf Energy Information’s Deepwater Development Conference, Madrid, Spain, March 27, 2025.
BRIAN PICCOLO has a master’s degree in petroleum engineering from LSU and is focused on the development of new technology in the oil and gas industry. As a Principal Systems Engineer at HMH, Mr. Piccolo is supporting the development of a fully electrified BOP for both surface and subsea applications. Previously, he has supported engineering and commercialization for multiple deepwater managed pressure drilling systems.
VIJAY CHATUFALE has a master’s degree in mechanical engineering from Oklahoma State University, and he has been involved in the development of various pressure control products used in oil and gas industry. As a staff engineer at HMH, Mr. Chatufale has been supporting the development of fully electrified BOPs, as well as other products, for both surface and subsea applications.
SHAH SAKHAWAT holds a master’s degree in electrical engineering, with a specialization in Power Systems, and he serves as a senior engineer at HMH. He has been deeply involved in the development of subsea power and control systems, contributing to technologies, such as a 20K and fully electrified BOP. Mr. Sakhawat is a licensed Professional Engineer in Power, with prior experience in the design of harmonic filters and VAR compensators.
RUNE SAUA has a degree in Power Electronics from the Stavanger Offshore Technical School, and he serves as a responsible expert for electrical installations. He has 15 years of experience designing VFD systems and is well-versed in industry regulations and standards, including IEC and NEK. In addition to electric bop, he has worked on robotics, shore power systems, winches and top drives.