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Schuman, Thomas (Missouri University of Science and Technology (Corresponding author) | Salunkhe, Buddhabhushan (equal contributor)) | Al Brahim, Ali (Missouri University of Science and Technology (Equal contributor)) | Bai, Baojun (Missouri University of Science and Technology)
Summary Preformed particle gels (PPGs) are 3D, crosslinked, dried polymer particles that can swell to several hundred times on contact with formation water. PPGs have been used extensively to control water production problems in reservoirs with conformance problems. The current state-of-the-art PPGs are polyacrylamide-based hydrogel compositions which lack long-term thermal stability under high-temperature and -salinity conditions. There are many oil reservoirs across the globe exhibiting conditions of temperatures higher than 120°C with high salinity. A novel ultrahigh-temperature-resistant PPG composition (DMA-SSS PPG) was designed to fill up the technology gap between existing polyacrylamide-based PPG technology that degrades readily over 110°C temperatures. DMA-SSS PPG exhibited excellent thermal stability for greater than 18 months in North Sea formation and formation water environments at 130°C. DMA-SSS PPG described herein showed swelling capacities of up to 30 times in different salinity North Sea brines. DMA-SSS PPG’s physiochemical properties like swelling, swelling rate, and rheological behavior were studied as a function of temperature and salinity. DMA-SSS PPGs showed excellent elastic modulus (G’) of about 3200 Pa in formation water of 90% water content. Thermostability of DMA-SSS PPGs was assessed at 130 and 150°C in North Sea brines with different salinity conditions. DMA-SSS PPGs proved to be stable for more than 18 months without losing molecular integrity. Thermostability was further confirmed through different metrics such as cross-polarization magic angle spinning carbon-13 nuclear magnetic resonance (CPMAS C NMR), thermogravimetric analysis (TGA), and morphology. Laboratory coreflood experiments were performed to demonstrate the plugging efficiency of open fractures and effectiveness in reducing the permeability. DMA-SSS PPG comprehensive evaluation confirms its novelty for excellent hydrothermal stability, thus can be used to control water production problems for mature reservoirs exhibiting conditions of high salinity and high temperature.
Craig Cipolla is a Principal Engineering Advisor in the Hess Technology Team, supporting the development of innovative technologies to enhance well productivity and oil recovery. Craig provides hydraulic fracturing, completions, and reservoir engineering support to HESS business units worldwide. Craig's current focus is the development of unconventional resources, optimizing completions and well spacing. His expertise in tight/unconventional reservoirs includes a unique combination of hydraulic fracturing, geomechanics/geophysics, and reservoir engineering skills. Craig's experience includes the design and optimization of fracturing treatments and integrated field studies in tight/unconventional and naturally fractured reservoirs in the U.S., Canada, Mexico, South East Asia, North Sea, South America, Australia, Russia, and the People's Republic of China.
Sun, Hao (Marine Technology Division, COSCO Shipping Specialized Carriers Co. Ltd / College of Shipbuilding Engineering, Harbin Engineering University) | Cai, Liancai (Marine Technology Division, COSCO Shipping Specialized Carriers Co. Ltd) | Sun, Mingyuan (Marine Technology Division, COSCO Shipping Specialized Carriers Co. Ltd) | Yuan, Meng (Marine Technology Division, COSCO Shipping Specialized Carriers Co. Ltd) | Yao, Hanwen (Marine Technology Division, COSCO Shipping Specialized Carriers Co. Ltd) | Wang, Andy (Marine & Offshore Operations, DNV Singapore Pte. Ltd)
ABSTRACT A mega topside of an HVDC platform located in the North Sea was transported by a DP-2 heavy transport vessel, M/V Xiang He Kou from Dubai, UAE to the German offshore installation site. After the voyage, the topside was successfully installed by dynamic positioning (DP) float-over installation method. This paper presents a comprehensive description of the engineering analysis, motion monitoring of the topside during transportation and installation. The vessel's motion analysis model is tuned and verified by the model tests, which ensure the accuracy of motion response analysis results. A motion monitoring system has been installed onboard to record the actual motion response at the topside COG throughout the voyage. The monitored results are compared to the design limits obtained from simulations during sailing in real-time, which are found well within the design limits. It is found that the concerned parameters are below the limits with sufficient safety margin and thus are well engineering covered. INTRODUCTION An HVDC platform is installed off the coast of Borkum in the German sector of the North Sea. The topside of the platform is the world's largest high voltage direct current (HVDC) station that converts the alternating current produced by the offshore wind turbines to direct current for export. The topside was transported by the DP-2 heavy transport vessel, M/V Xiang He Kou, from Dubai, UAE to the German offshore installation site. After the transport voyage, the topside was successfully installed by dynamic positioning (DP) float-over integration method. Before sailing, the motion and acceleration response of the vessel CoG, and the topside CoG under the design environmental conditions are analyzed. The voyage operational limiting weather conditions are also defined according to the guidelines for marine transportations (GL Noble Denton, 2016). By following the operational limit and operational criteria, the captain can decide to maintain the planned route, or change the heading to avoid the severe weather, based on the daily weather report and forecast along the planned route. During the whole transport, the motion and acceleration of the vessel and the topside CoG were real-time monitored and interpreted by the onboard installed Octopus-onboard server during the sailing. The real-time motion statistics and motion prediction based on the weather forecast will be supportive to the captain to lead a safe voyage.
Le, Tuyen Quang (Institute of High Performance Computing) | Dao, Ha My (Institute of High Performance Computing) | Lu, Xin (Institute of High Performance Computing) | Bangar, Inez (Institute of High Performance Computing)
ABSTRACT In this study, we explore the ability of the full connected neural network (FCNN) in prediction of phase-resolved uni-directional and multi-directional waves in various wave conditions in a typical offshore engineering application. The neural network models are trained on random waves that are generated by the JONSWAP spectrum with significant wave height and peak spectral wave period taken from the North Sea wave data. The selected wave steepness varies from 0.01, 0.017 to 0.038, which covers mild to steep waves. Linear Wave Theory (LWT) could provide reasonable accuracy for mild wave conditions but less accurate for steeper waves. The FCNN gives more accurate results in phase-resolved prediction of average steepness cases in multi directional waves. INTRODUCTION Wave prediction in ocean and offshore engineering has been advancing rapidly. Several models (WAMDI, 1988; Booij et al., 1999) can give information of statistical quantities: significant wave height (Hs), peak spectral period (Ts) and mean wave direction. However, rapid phase-resolved prediction of wave propagation has still been a challenging topic for researchers due to fully non-linear physics. In the initial effort of phase-resolved prediction, the linear wave theory (LWT) based on potential flow was proposed in early 1990, it is simple but only works for small steepness and short-term prediction (Morris et al., 1998; Ruban, 2016). Thanks to advances in the machine learning (ML) in computer science, the non-linear problem in engineering can be solved or partly solved. The neural network model can quickly predict a result in online stage after being trained on available data in offline stage. More recently, with advanced neural network being rapidly developed, its application has widely used computer vision, fluid dynamics and control. Therefore, deterministic wave prediction using ML in real-time has become possible. The short-term deterministic wave prediction plays an important role in the efficiency of maneuver operations which take only few minutes but being crucial in operations of ocean platform. These include takeoff and landing of helicopters, dynamic positioning of floating structures or vessels and rescues operations. To meet these practical applications, both accuracy and speed in wave prediction are required. Researchers therefore have strongly focused on using ML to build a prediction model for ocean waves. The wave height can be predicted accurately in several ML models: Long short-term memory (LSTM), the Artificial neural network (ANN) and hybrid models with combination of nonlinear autoregressive exogenous (NARX) (Ren et al., 2018; Fan et al., 2020). The phase-resolved prediction in multi-directional steepness wave has hitherto been challenged for researchers even though there are some reports for uni-directional long-cress wave (Law et al., 2020; Duan et al., 2020).
Abstract Magnesian calcite has been identified as the main constituent of solids fouling several bp facilities in the North Sea and Azerbaijan and in partner operations in other locations. These solids were, for many years, thought to be calcite scale for a number of reasons. The deposits formed compacted solids and thus looked similar to scale, they effervesced and dissolved in acid and calcium was detected as the main constituent. XRD analysis, however, revealed the deposits were magnesian calcite. The inclusion of magnesium into the crystal cannot be co-precipitated with calcite scale under typical oilfield conditions and timelines and their deposition cannot be controlled by conventional scale inhibitor injection. These solids, transported from the reservoir with the produced fluids can act as scavenger sites, reducing the effective concentration of scale inhibitors available to manage conventional scale deposition. The fact that these solids, in many ways, present themselves as a conventional scale has perhaps hidden the extent of their occurrence in offshore and onshore operations. Magnesian calcite has been identified as the main constituent of retrieved solids that were (1) adhered to tubing and restricting production in a North Sea field (2) impacting operation of subsurface safety valves in both North Sea and Caspian Sea operations (3) reducing the efficiency of heaters and coolers offshore North Sea and onshore in the Caspian and (4) plugging strainers in the produced water handling systems offshore North Sea and onshore Caspian. This paper will describe how this ‘pseudo scale’ was detected and its prevalence, using field case examples from several bp operated and non-operated assets. It describes the theories developed to rationalise magnesian calcite deposition onto production surfaces including the possible role of ‘sticky’ molecules and the technology bp is evaluating to holistically manage this fouling phenomena. It will share dispersant chemical field trial performance data and the deployment of electromagnetic fields to determine the impact of changing zeta potential on the attraction of fine magnesian calcite particles to the surface and thus the fouling rate.
Abstract HDPE lining has been used offshore for reeled water injection lines since decades, especially in the North Sea. It has been proven to be a cost-effective alternative solution to CRA materials when corrosion allowance is not an option. There have also been several developments in the last years to unlock the use of HDPE lining for other pipelay methods, using HDPE sleeves for the field joints. This paper presents investigations performed on the use of HDPE lining for a study case of a corroded water injection network replacement in a shallow water environment. A case study has been built based on a typical shallow water architecture including several platforms, connected to a shared water injection network. It is composed of a large water pipeline on which each platform is connected through a static riser, some spools, including goosenecks, a small water line and a shutdown valve. Design, system architecture and manufacturing of such pipe network to be prefabricated onshore were investigated to assess technical feasibility and costs of HDPE lining as an alternative to CRA (Corrosion Resistant Alloys). It is technically feasible to have HDPE lined static risers and spools which include short radius bends and goosenecks with basically any shape. Additional lined flanges (when compared to a usual steel or CRA lined assembly) have to be added to allow for the connection between straight and bended sections of the tie-in connections. Any spool or riser shape can be prefabricated, assembled and tested onshore prior to be installed offshore as a classical static riser or spool. The use of the FBJ (Fusion Bonded Joint) technology developed by Saipem was considered to try to further reduce the costs of such design and to reduce the quantity of lined flanges. Even with the additional lined flanges required for the HDPE lined riser/spool assembly, there is significant room for cost savings since expensive CRA lining materials will not be used. While the usual investigations/developments with HDPE lining usually focuses on water pipelines, this study focused on the rigid pipe connections such as static risers and spools, to be prefabricated onshore and presents a technical solution to use HDPE lining for such applications. This could typically be used for corroded water injection network replacement as an alternative to expensive CRA materials and would allow to consider full network with HDPE lining as an option.
Abstract The use of monobore expandable systems has been theorized in previous works (Dean 2003, Dupal 2002) with various proposed embodiments. Commercially available sizes are limited to 8-1/2 and 12-1/4 wherein the size designation refers to the drift diameter which the monobore system may pass through and the post-expanded drift diameter of the monobore liner. In particular, the 12-1/4 in. size has a run history which includes a recent successful commercial installation (Baker 2021). An application within the North Sea where significant pressure gradients are typically encountered during drilling of a 6-1/2 in. section below the 7-3/4 in. base casing was identified as a candidate to leverage existing monobore expandable technology in a 6-1/2 in. size. Monobore expandable technology is the preferred method to manage challenges presented by steep pressure gradients or fluid loss zones while drilling due to the robustness of a solid steel barrier with external isolation seals, which may be cemented in place without a reduction in wellbore diameter. Beginning with the 12-1/4 in. platform and scaling down to a 6-1/2 in. platform created challenges regarding geometry, critical load ratings, and achieving post-expanded system ratings. A feasibility study was performed which relied heavily on finite element analysis to determine the possibility of the system scale down from 12-1/4 in. to 6-1/2 in. The analysis proved the design of a monobore expandable system in the 6-1/2 in. size based on the requirements for the North Sea application. It also proved that the design would require a non-standard pipe size. The pipe and expansion system were tested in a series of surface level qualification tests and at a test rig within a downhole environment. The results of testing validated the finite element analysis approach to the feasibility study and proved system readiness for field qualification trials.