ARC Advisory Group
AsOffshore's readers know all too well, designing, constructing, and operating an offshore production facility in a safe and environmentally responsible manner is difficult and complicated. It involves multiple groups internal as well as external to the owner-operator, and multiple disciplines with different responsibilities and different functions. In particular, the lifecycle of an offshore production facility has many phases, beginning with conceptual design and continuing through operations and finally decommissioning.
As many energy companies have learned, advanced simulation incorporating a common modeling environment with consistent models across the lifecycle of an asset can facilitate this intricate procedure.
Today's owner-operators use advanced, software-based simulation tools to perform conceptual design of a subsea production system and the topside production facility. One main purpose of the conceptual design is to develop a flowsheet of the production process and to establish the size and configuration of piping and equipment such as pumps, compressors, and separators. This is often accomplished using a steady-state model that incorporates material and compositional data determined from a sample of production from the reservoir.
In detailed design, accuracy rather than speed is paramount. Therefore, compre-hensive analysis using complex rigorous models that consider every facet of the process is highly desirable. Here, by adding increasing detail and complexity, design engineers transform simple conceptual models to high-fidelity models that accurately represent the process. This way, they can refine and transform the conceptual design into a detailed design that forms the basis for bids from vendors.
Companies are leveraging efforts put into steady-state models to develop and use consistent dynamic models. For offshore projects, dynamic simulation can help de-sign the control system and other elements such as the inlet size to topside separators that are sensitive to transients and slugging phenomena. Operators also use the dynamic simulation during commissioning to help identify problems.
Increasingly, new projects are in less-developed regions of the world and often re-quiring local participation in operating the facility, regardless of the experience or skill of the local workforce. The dynamic models used for design can be the basis for training simulators to increase the proficiency of the local operators. The major concern with training simulation is realism; it must simulate the response of the process to disturbances to the operators' adjustment in real time.
In the past, models built for design purposes were never reused. This discarded valuable data, information, and knowledge, resulting in duplication of effort in later phases. Today, leading owner-operators leverage this knowledge across the total lifecycle of an asset. This lifecycle approach helps lower costs, identify and resolve problems better, and shorten development time for various simulation systems.
Simulation as a collaboration tool
Many organizations fail to take advantage of data, information, and knowledge creat-ed by different departments or in different phases of a project. This results in duplicated effort which increases costs and lengthens design cycles. Leveraging modeling efforts across the asset lifecycle ensures the use of accurate and consistent models for design, operations, control and management technologies, and facilitates knowledge reuse and collaboration.
When designing an offshore production facility, owner-operators typically make dif-ferent teams responsible for different aspects. The subsea team is responsible to get the oil to the surface. The topside team is responsible to design the surface processing facility. Within each team are multiple disciplines such as reservoir, production, and processing engineering as well as transport specialists. Increasingly, leading owner-operators use a common simulation and modeling environment as a collaborative tool among different groups around the world. The common model and simulation environment provides a common basis for communications for all disciplines, acts as a repository for data, and promotes collaboration among the groups.
Open standards increase versatility
In the past, many of the simulation tools in upstream oil and gas were incompatible or used different models, making collaboration difficult for different departments or disciplines.
For the design of an offshore production facility, owner-operators typically contend with many legacy models, proprietary thermodynamic packages, and other third- par-ty simulation tools. For instance, the actual reservoir itself is modeled using a different simulation software package. The reservoir, subsea production system, and topside processing facility are, in essence, a continuous process. Changes in the reservoir affect the topside processing facility, which in turn, affects the re-injection of gas in the well, which affects recovery, and so on. Today's common simulation environments integrate the subsea production system with the topside processing facility; but the reservoir remains outside of its domain. Standards-based architectures can facilitate exchange of results between different software programs.
The open architecture also allows the owner-operator to incorporate its own models and thermodynamic packages into the simulation environment. They also can incorporate third-party multi-phase pipe flow models into the simulation environment.
To remain proficient, today's owner-operators must continue to improve workflow methods to increase efficiency and productivity, reduce costs, and facilitate collabora-tion across all project phases, including both operations and, ultimately, decommissioning. Using a common modeling method can promote facility lifecycle benefits through data reuse and collaboration by linking different phases and functions such as conceptual design, costing, detailed engineering, operator training, process improvements, optimization of operations, etc.
By adopting a common model approach where appropriate, owner-operators can exploit the full and considerable lifecycle benefits of their simulation tools. However, this requires buy in and support from different groups within an organization to break down the silo mentality and to result in collaboration on different aspects and phases during the lifecycle of an asset.
Tom Fiske, senior analyst Automation & Supply Chain, ARC Advisory Group, is part of the Automation Consulting team at ARC. He focuses operations management, process simulation, operator training simulators, advanced process control, asset optimization, and collaborative production management markets. Contact the author at firstname.lastname@example.org.
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