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Collaborating Authors
Candelier, C.
Abstract Hydrates, solid crystals looking like compact snow (gas system) or slurry (oil system), are formed of water and gas at high pressure and low temperature (Figure 1) [1]. These conditions are usually encountered during shutdowns and restart operations in deepwater environment. Considering the associated production shortfalls and the cost of offshore remediation means, line blockage due to hydrates formation must be avoided [2]. And as a consequence, one of the main constraints in the design and operation of deepwater subsea developments has often been the management of hydrates in the production flowlines.
- South America > Brazil (0.46)
- Africa > Angola (0.29)
- North America > United States > Texas (0.28)
- Europe > France (0.28)
- Production and Well Operations > Production Chemistry, Metallurgy and Biology > Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (1.00)
- Facilities Design, Construction and Operation > Flow Assurance > Hydrates (1.00)
Abstract This paper presents a comparison between field data from a West Africa deep offshore field operated by TOTAL and software available for design engineering. Multiphase flow simulations have been performed for several production loops to evaluate the software ability to reproduce steady state operations (slugging, pressure and temperature profiles, etc.) and the full preservation sequence including shutdown and fluid displacement by dead oil circulation. Results show that software predictions are generally in good agreement with field observation especially with regards to pressure variation and timing. However the structure of the interface (i.e. mixing zone) between the cold dead oil and the live oil is not well reproduced for the loop operated in hybrid mode (i.e. only one branch in production, the other one being already preserved with dead oil). Introduction In oil dominated systems, one of the most common means of preservation against hydrate formation in deep water subsea production networks is to displace the live oil by circulation of stabilized dead oil. In a conventional design, the dead oil is pumped from the cargo tanks and the production lines and risers are looped to allow circulation from both ends. However ensuring the displacement of a multiphase production fluid sitting in deep water risers and flowlines involve complex transient phenomena such as thermal effect (cooldown and warm-up, cold spots effects as manifolds, subsea connectors), occurrence of important pressure variations (depressurization, packing, unbalanced liquid head in risers) and multiphase flow effects (phase segregation, fluid displacement, liquid slugs). In design phases, it is required to model in detail the full preservation sequences to optimize the thermal specifications of the equipment and demonstrate the capabilities of the subsea system to stay free from hydrate formation during the preservation planning considered and to design relevant circulation pumps, etc. Flow Assurance engineers then use commercial multiphase flow software for the design of field development facilities.
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Multiphase flow (1.00)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (1.00)
- Facilities Design, Construction and Operation > Pipelines, Flowlines and Risers > Risers (1.00)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (1.00)
Abstract Subsea pipeline electrical heating is a relatively new technology in the Oil & Gas industry that has been developing, quite intensively during the last 15 years. There are two main techniques considered for subsea pipeline electrical heating; the first one, already deployed and in use, is Direct Electrical Heating (DEH) and the second one, currently in the final stage of the technology readiness process, is Electrical Heat Tracing (EHT). Electrical heating of subsea pipelines is expected to be increasingly deployed as an elegant technical solution to optimize the flow assurance management during production pipeline's service life and as a cost saving solution bringing significant reduction of projects overall CAPEX and OPEX. TOTAL has been operating world's unique EHT PiP (Pipe in Pipe) subsea system, installed as an industrial pilot as a part of the Islay (TOTAL UK) project. Following the success of Islay project, TOTAL has studied implementation of the EHT PIP technology for an on-going deep water brownfield development which consists in the production of new reservoirs as a subsea tie back to an existing FPSO. The "base case" field architecture, a hybrid loop concept, had been selected at initial conceptual study stage. Nevertheless, due to high CAPEX of the "base case" option, TOTAL decided to investigate alternative solutions for the preservation of the subsea production line during shut-down, among which an EHT system appeared as potentially attractive. Therefore, a study was conducted in order to assess if the EHT system is installable, safe, reliable, operable, efficient and environmentally sound throughout its required minimum operating life of twenty (20) years.
- North America > United States > Texas > Terry County (0.41)
- North America > United States > Texas > Gaines County (0.41)
- Europe > United Kingdom > North Sea > Southern North Sea (0.41)
- Europe > United Kingdom > North Sea > Southern North Sea > Southern Gas Basin > Silver Pit Basin > Block 49/30c > Davy Fields > Brown Field > Rotliegend Formation (0.99)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/11 > Åsgard Field > Åre Formation (0.99)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/11 > Åsgard Field > Tofte Formation (0.99)
- (43 more...)
ABSTRACT: Subsea processing technologies are becoming new solutions for subsea production enhancement for new deepwater field developments but especially for brown fields where subsea oil/water separation and water re-injection into reservoir is particular relevant to generate spare capacity on host platform. This usually requires efficient bulk oil/water separation coupled potentially with additional water treatment to cope with stringent residual Oil in Water and Solids in Water requirements in order to re-inject/dispose safely after treatment produced water. SAIPEM is currently developing an efficient and compact liquid/liquid separation system based on cyclonic technology to propose an alternate solution to gravity separation systems (as implemented on Troll and Tordis) having operating limits and potentially fabrication issues; and to propose a solution compliant with deepwater requirements. The SAIPEM cyclone is based on an innovative geometry to improve the system flexibility to tolerate both flowrate and composition variations at the system inlet; but also to propose a self-regulating system tailor-made for subsea applications. Extensive computational works have already been performed to optimize cyclone internal geometry, to improve separation efficiency and to define the system dynamic regulation. All results have been confirmed through an extensive test campaign carried out with a full scale cyclone and two synthetic oils under several flow conditions to simulate all the field lifetime operating conditions. Test campaign proved the excellent separation performances and the efficiency of the system for all tested operating conditions and confirmed the self-regulation of the system. This regulation is largely simplified and limited compared to conventional cyclones and achieved by means of only one single valve infrequently actuated. Based on the excellent results of the qualification test campaign, 3C cyclone appears to be particularly suited for various applications ranging from topsides pre-treatment to deep and ultra-deep water applications. According to some optimizations, 3C cyclone design can be easily adapted for both gas/liquid separation and de-oiling applications, and allows foreseeing full cyclonic subsea stations development providing high separation efficiency, self-regulation, as mitigating sand accumulation issues into the system. In the paper, 3C cyclone development will be presented. Emphasis will be placed on 3C cyclone description, test campaign results, potential applications and subsea station arrangements that might be envisaged following 3C cyclone development activities. Benefits in term of separation efficiency, control, availability, flexibility and arrangement will be also discussed and compared to conventional solutions for the different applications
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.34)
ABSTRACT: Dry-tree production units are continually being evaluated, selected and installed for deepwater developments worldwide. These units involve floating host platform housing drytrees Top Tension Risers. Drilling and intervention facilities are selectively integrated on vessels to take advantage of the direct accessibility of the wells located below the platform. In the context of deeper and buried reservoirs demanding long and constraining drilling operations (extended wells, horizontal wells...); these dry-tree production platforms eliminate the need to mobilize dedicated vessels for drilling and workover activities and lead to significant cost and time savings and improved availability. West African unique metocean conditions allow deepwater field operators to consider spread-moored barge to support both surface wellheads and perform drilling operations. The Wellhead Barge is a unique spread-moored technology taking advantage of benign metocean conditions of Gulf of Guinea to offer a single vessel as drilling and production supports for field development. This feature integrates on a cost effective, standard and high carrying capacity hull the drilling, completion and work-over facilities, houses dry-tree production risers into a central wellbay and is able to support any kind of processing plant ranging from no processing at all (next to FPSO) to full process. Self standing top tensioned risers considerably reduce interfaces with the barge and provide to the concept operational advantages, such as possibility of fixed drilling rig at the centre of the barge due to easy riser transfer and dedicated intervention / workover equipment along the wellbay for simultaneous operations. This paper will present the main features of a full processing Wellhead Barge designed to accommodate up to 36 dry-tree production wells, fitted with autonomous drilling rig and equipped with specific intervention / work-over equipment. Emphasis will be placed on the specific arrangement of drilling facilities and wellbay housing dry-tree production risers which provide to the concept a high safety level by segregating functions and high availability where simultaneous drilling, well intervention and production operations might be performed. Benefits in term of vessel operability related to the specific wellbay and drilling equipment arrangements will be developed by means of results of computational studies and extensive model tests campaign. Technical maturity of the design, economical advantages which results from the use of Surface tree barges and the possibility of simultaneous operations in term of CAPEX and OPEX will be also developed