The Zohr subsea production system, around 180 km off the coast of Egypt in 1,500-m water depth, was configured with a novel metering system providing the necessary functionalities for optimized hydrate inhibition. Different subsea measurements from startup and normal production phases were obtained and combined to extract valuable information regarding water production and to monitor hydrate inhibitor dosage in real time. Conventional hydrate inhibition system overdesign and overdosage would have had a significant impact on the technical and financial viability of the Zohr development, considering that no monoethylene glycol (MEG) regeneration capability was available at startup due to the fast-track nature of the project. Therefore, it was critical to limit the use of MEG, selected as hydrate inhibitor, in order to manage the available storage capacity. A data interpretation model was developed for the subsea water analysis sensor based on flow loop testing and analytical methods, allowing for real-time measurement of the MEG dosage for each well. Flow assurance modeling was performed to validate subsea measurements, and to explore model limitations and enhancements. Field data comparisons provided unprecedented insight into unexpected reservoir behavior several weeks faster than measuring fluids arriving onshore, considering the 220-km tieback distance. Indeed, the produced fluids at startup contained water at an order of magnitude more than initially expected, which would normally have resulted in underinhibition and a possible hydrate blockage risk. The subsea measurement system allows for MEG dosage to be monitored and injection flow rates to be adjusted in real time, from the first day of production, to respond to the fluids produced subsea. With only two wells initially producing in a 26-in, 220-km-long flowline, up to 5 weeks were required until produced water was received onshore for sampling. Data analytics were applied to validate the measurements obtained, identify trends, and anticipate onshore fluid arrival conditions weeks in advance. The field data also allowed to identify areas requiring improvement and to specify additional functionality development needs. The use of innovative subsea metering and measurement systems has enabled a safe startup of the field while meeting the first-gas target date. This is the first time in the industry that a direct hydrate inhibitor concentration monitoring and control, aimed at real-time hydrate management, has been achieved subsea for gas fields. The success of this innovative application of a subsea water analysis sensor was made possible through an unusual level of collaboration and openness between the field operators and subsea hardware providers. The cooperation that occurred on the Zohr Field development, from early engineering activities to operational support, has allowed for the combined team to advance the data interpretation models, improve the concept and obtain great value from the subsea measurements. This pioneering application of subsea technology is a game changer that will enable unlocking additional long-distance deepwater gas reserves.

Over the last decade, a number of subsea solutions have been deployed to unlock the commerciality of deepwater fields and increase the overall recovery factor of the reservoirs. Numerous types of monitoring and measurement technologies have been developed and installed downhole, subsea, and topside, but usually in a fragmented manner. The traditional field surveillance approach often addresses the reservoir challenges separately from issues that may affect flow in the production network or from processing facilities considerations. The value of information obtained using sensing equipment is then not fully taken advantage of, and critical information is lost due to the lack of integration. The objective of this work is to link all data collected along the fluid journey from the reservoir to the process facilties in order to optimize its production and better manage reservoir recovery. In this work, a novel integrated production management solution (IPMS) is introduced. Dedicated subsea and subsurface metering devices, advanced flow control equipment, production surveillance systems, and production optimization tools are combined to increase the understanding of the reservoir and subsea production network, maximize the value of the subsea hardware and address operational challenges to enable increased predictive flow assurance capabilities and production optimization. Bridging the gap from abstract measurement values to production management decisions, such as inflow control actuation; allow a better reservoir management implementation along of the field life, leading to an increased recovery. The functionality of the system is designed to address a number of challenges, including the following:reservoir management—recovery increase by combining continuous downhole sensing, seabed data, and IPMSEquipement centric monitoring and predictive maitenancethermal management—increase in system no-touch time and improved system preservationhydrate management—opex savings in regards to hydrate inhibitor injection and regenerationliquid management—avoiding unexpected shutdowns due to liquid surgespigging optimization—potential for reduced production losses during pigging operation and reduced pigging frequencylow temperature management—material integrity and hydrate preventioncorrosion and scale inhibition optimization—completion, subsea production system (SPS), and pipeline integrityerosion monitoring—SPSs and pipeline integrity. For the first time, integrated production data are used in online pore-to-process integrated models to guide reservoir decisions, optimize opex, and enhance recovery. Specific examples such as detection of reservoir property changes and their impact on recovery, optimized inorganic scale, and hydrates management based on integrated downhole seabed and process data are discussed in detail.

The oil and gas industry has long perceived computational fluid dynamics (CFD) as a computationally expensive, high-end simulation method to analyzing extremely complex behavior. However, the recent increase in computational power and the democratization of CFD packages have enabled 3D modeling to become part of the regular in-house execution scope. This paper presents a range of flow assurance CFD applications and shows the impact of 3D workflows in the overall system design, the adoption of standard specifications, and fast-track project executions. As oil and gas fluid journeys from the reservoir pore space to production facilities, it faces a wide range of complex flow assurance issues related to the nature of the live production fluids (compositional changes, viscosity, compressibility), the production system environment (high and low pressures) and its interaction with hardware (erosion, flow induced vibration, scaling). One-dimensional mechanistic models are used to solve these flow hindrance issues in wells and pipelines but provide limited results in the complex geometries of subsea and subsurface equipment. In subsurface applications, a CFD workflow was used to tune near-wellbore reservoir properties based on advanced 1D and 3D thermal modeling of the completion interval. Accurate thermal modeling was then used to manage downhole flow assurance issues (e.g., asphaltenes and scale buildup). In subsea equipment, the methodology was used to fast-track project execution by using standardized equipment using project specific parameters at an early stage. CFD analyses were used to estimate the risk of erosion and flow-induced vibration in a subsea tree. The thermal aspect was not neglected because CFD conjugated heat transfer was used to detect cold spots and improve the thermal behavior of insulated equipment (trees, manifold) during normal production and shutdown. To avoid long and expensive material qualification campaigns, CFD was used to define the temperature gradient in trees and compare the design temperatures of materials against their calculated temperatures. The ability to perform advanced CFD calculations has become a true enabler in the ability to adopt standardized equipment and supplier-led specifications on subsea field development applications, thus contributing to better capital efficiency and shorter time from discovery to production. Several concrete examples from wide-ranging subsea field development projects worldwide are presented to illustrate the added value of CFD in all stages of engineering, from concept definition to project execution.