Electrical-submersible-pump (ESP) technology is a proven artificial-lift method for shallow, low-pressure reservoirs such as those found in the West Sak viscous oil field in Alaska. This study examines how subsea processing (SSP) can develop into an important enabling technology for future ultradeepwater-field developments and long-distance tiebacks. Unconventional production patterns in the Permian Basin are leading producers to replace electrical submersible pumps (ESPs) with gas lift, which had been little used there. The sharp downturn in the offshore oil business has sparked interest in using subsea pumps to add production. If those conversations turn into orders, it may convert this rarely used option into a commonly used tool for extending the life of offshore fields.
Devon Energy and its debt gets smaller, as Canadian Natural Resources adds to its huge, long-term bet on Canadian heavy and ultra-heavy crude. The recent production freefall could accelerate even further as US sanctions-related deadlines pass, the US Energy Information Administration said. The authors of this paper propose a novel work flow for the problem of building intelligent data analytics in heavy-oil fields. This paper presents the data collected by an ultrasound downhole scanner, demonstrating a novel method for diagnosing multilateral wells. Against the background of a low-oil-price environment, a redevelopment project was launched to give a second life to a shallow, depleted, mature offshore Congo oil field with viscous oil (22 °API) in a cost‑effective manner.
UK operator Trident Energy is entering Brazil while Australian firm Karoon Energy is expanding its position in the country. Both will try to boost output from already-producing assets. Petrobras says it can produce oil for a lower break-even price than onshore shale plays, including the Permian Basin. Brazil’s offshore sector has cut the cost of deepwater production but comparisons based on break-even prices are slippery. Take a quick look at some of the data points shaping upstream headlines and the movement of oil supplies around the world.
Africa (Sub-Sahara) Oil was discovered at the Ekales-1 wildcat well located in Block 13T in northern Kenya. The well has a potential net pay of between 197 and 322 ft in the Auwerwer and Upper Lokone sandstone formations. Tullow (50%) operates 13T with partner Africa Oil (50%). The Mzia-3 appraisal well in Block 1 off Tanzania encountered a combined total of 183 ft of net pay in the Lower and Middle sands and confirmed reservoir quality in line with that seen in the Mzia-1 and Mzia-2 wells. Asia Pacific The Luba-1 offshore well on Brunei Block L was spudded. The well will evaluate the hydrocarbon potential of the Triple Junction structure. Serinus has a 90% interest in Block L, through indirect wholly owned subsidiaries Kulczyk Oil Brunei (40%) and AED SEA (operator, 50%).
To address flow assurance challenges, Integrated Production Bundle (ETH-IPB) and Heating Cables Replacing Armour Wires (ETH-HCRAW) have been developed. These two technologies use electrical cables, which provide heat to the fluid by Joule effect. They are different in their design, efficiency and cost, and thus on their application domains. This paper details the design, the qualification and the identified envelop of use of the ETH-HCRAW.
The pioneer flexible pipe with active heating technology was ETH-HCRAW, i.e. flexible pipe with electrical cables integrated in the tensile armour layers for active heating and such application is developed in the paper. The integration of the active heating in the flexible and the terminations is presented. The overall qualification of this technology is described considering two different levels. Firstly, the qualification of the components of the electrical system through extensive electrical and mechanical tests is developed. Then, the global mechanical behavior and the reliability of the overall system are demonstrated by a phase of full scale tests.
Such solution based on integrated electrical cables has been demonstrated to be a safe and effective technology for active heating on flexible pipe through dedicated R&D development back in the early 2000’s. This paper presents the latest developments that enable to position the ETH-HCRAW technology as leading solution for active heating with the advantages of flexible pipes. ETH-HCRAW facilitates the exploitation of deep water projects and long tie back by limiting the temperature losses along the lines. Active heating, by increasing the temperature of the fluid, enhances flow assurance for complex and viscous fluids by reducing the viscosity and reduces wax appearance in the lines. Finally, this technology tackles the formation of hydrates by maintaining a minimum temperature during shut down and start-up phases allowing to remain outside the hydrate formation conditions.
ETH-HCRAW is an attractive and cost effective active heating solution with a broad possible domain of application. This technology offers many advantages in terms of flexibility of operation especially for hydrate and wax management. This paper details the numerous advantages and the limitations of this technology compared to other active heating technologies.
Malikai field, located offshore Malaysia at a water depth of 500 m, was brought on stream in December 2016. The field is developed using tender-assisted drilling and completions from a Tension Leg Platform (TLP) – a first in Malaysia. The TLP is a conventional 4-column, ring-pontoontype hull structure that connects to asemi-submersible type TAD vessel through nylon hawser ropes which together with chain-polyester-wiremoorings on the TAD and TLP allow for station-keeping during drilling operations. This paper describes the design, analysis and operational experience of the coupled TLP-TAD mooring system. Design of the coupled mooring-hawser system was driven by the need to not only keep TLP excursion limits for risers but to also maintain the gangway within its stroke limits. In addition, there was a need to move the TLP over short distances by winching the TLP and TAD moorings to facilitate latching of the top-tensioned risers and to maximize drilling uptime. Understanding the strongly nonlinear stiffness behavior of nylon rope was crucial in ascertaining these safety and functional requirements. Several numerical simulations were performed and were supplemented by wave-basin and rope stiffness tests during design validation. Marine instrumentation systems were incorporated on the TLP from which real time environmental data, TLP and TAD conditions, and mooring and hawser tensions are obtained. These measurements are used to calibrate numerical models for mooring advisory. Station keeping during drilling operations were managed through daily interface between offshore and onshore teams for winching plans recommendations for TLP repositioning and to predict station keeping responses based on short-term weather forecasts. Collaborative interface with the risers, wells and facility-operations teams has proved valuable in safe and effective station keeping during the drilling campaign.
Subsea Flowlines blockage due to hydrate or paraffin plugs, resulting from pour point issues or deposition, is a frequent concern in subsea production requiring expensive remediation methods. The expenditures associated with subsea flowlines unplugging can increase very quickly, especially when considering the associated loss of production as well as the various investigations needed to define the appropriate remediation strategy. Such investigations cover the identification of the plug's nature, its location, the assessment of the appropriate dissociation method as well as the flowline restart strategy.
In some scenarios, the plug dissociation method, like depressurization for hydrate plug and chemical soaking or pigging for paraffin plug, may take a long time ranging from several days to several months. Often, the remediation cannot be performed from the topside facility and will require the mobilization of an external drillship vessel to carry manifold or Xmas tree work over. Ultimately, the plug removal method may fail and therefore lead to flowline abandonment and/or replacement. From these observations, there is room for the development of a more efficient, predictable and reliable method to unplug subsea flowlines. With this regard, the development a new subsea flowline intervention system named Electrically Trace Heated Blanket (ETH Blanket) has been initiated.
The ETH-Blanket is a compact and modular system, with length adaptable typically up to 2km. The system is equipped with trace heating cables relying on Joule's Effect for heat generation to dissociate the plug and distributed temperature sensing (DTS) to monitor the flowline's bore temperature in order to identify the location of the plug, characterize its nature and follow-up the temperature and pressure profiles during plug dissociation. The ETH Blanket can be deployed onto any kind of existing flowlines (flexible or rigid) and in any condition (buried or not) from a Light Construction Vessel. The power required to dissociate the plug is low (typically <1MW) and once the dissociation is completed, the ETH Blanket can be recovered onto the intervention vessel and relocated.
This paper describes into details the ETH-Blanket assembly and its operating principles, its anticipated thermal performances determined using CFD modeling, as well as and its deployment method and spread. To illustrate the ETH-Blanket efficiency, a typical multiple hydrate plugs dissociation operation will be presented and compared to a conventional topside depressurization.
As a conclusion, the on-going fast-track qualification programme for the development of the Electrically Trace Heated Blanket Technology will be presented.
Tzotzi, Christina (Forsys Subsea) | Parenteau, Thomas (Forsys Subsea) | Kaye, David (Technip) | Turner, Douglas J. (ExxonMobil Development Company) | Bass, Ronald (ExxonMobil Development Company) | Morgan, Julie E. P. (Woodside Energy Ltd) | Zakarian, Erich (Woodside Energy Ltd) | Rolland, Julien (TOTAL Exploration & Production) | Decrin, Marie-Kathleen (TOTAL Exploration & Production)
Electrically Traced Heated Pipe in Pipe (ETH-PiP) technology has been developed to overcome some of the challenges associated with deeper and more remote offshore oil and gas production. This active heating technology applies power to achieve a production fluid temperature above the wax or hydrate appearance temperature either continuously, during normal production, or intermittently, during shutdown periods. Concerning hydrate management, the contractor Company in collaboration with Major Operators conducting experimental and modelling studies to investigate hydrate dissociation in heated flowlines through a Joint Industry Project (JIP) kicked-off in 2012. The main objective of these investigations is to demonstrate that a long, non-permeable hydrate plug can be dissociated in a safe and controlled manner with the ETH-PiP technology.
Large hydrate plugs (approximately 200 kg each) are formed in an 18m ETH-PiP 6? OD prototype, using a water and gas system equipped with DTS fiber optics systems for temperature monitoring, pressure and temperature sensors, and high accuracy gas flow meters. Different heating strategies are tested to investigate the best active heating procedure for safe hydrate plug dissociation, using temperature, pressure and released gas flow rate monitoring along the entire length of the prototype. Hydrate plug dissociations are performed in open or closed volumes for various conditions during the 2nd phase of the experimental campaign, which started at the end of 2013. High pressure differentials are applied across the hydrate plugs; non-uniform longitudinal heating profiles are applied to reproduce operating conditions similar to direct electrical heating; and three-phase dissociation experiments are conducted to simulate the influence of oil present in the hydrate pores on the plug dissociation.
The paper gives an overview of the experimental set-up and measuring techniques used. It describes the hydrate plug formation, location, and characterization, as well as the successful dissociation of hydrate plugs. Preliminary simulation results based on a specifically developed "in-house" simulator are presented, as well as extrapolation of the results to real subsea conditions. This test program demonstrated that large non-permeable hydrate blockages in single line field architectures could be dissociated without local pressure build-up or plug run-away using ETH-PiP technology.
Active heated pipe technologies are enabling solutions for field developments allowing cost effective management of flow assurance to overcome specific challenges like longer distance tie-backs and greater water depths.
This paper introduces wax and hydrate issues and conventional approaches to manage them. It highlights the need for other approaches, such as active heating technologies, to reach longer tie-back distances and greater water depths.
It reviews Direct Electrical Heating (DEH), Electrically Heat-Traced Flowline (EHTF), and active heated flowline bundles comprising Hot Water Circulation (HWC) and EHTF in bundle. A general presentation of these systems is given, including design, fabrication and installation methods, as well as the maturity of the technology. Typical field architecture is proposed to illustrate the benefits of each active heating technology in terms of field development optimisation.
This paper provides global information and an understanding of different available solutions for active heating pipeline systems, with technical and economic perspectives, and concludes with elements for selection of optimised field architecture.
Wet DEH is a field proven technology with large track record that has already been installed on a 43km pipeline in 1070m water depth. It fits production fields not requiring high thermal insulation performances and thus allowing wet insulated pipe (U-Value =2W/m2.K). The system presents high electrical power requirement (50-150W/m). Therefore, infrastructure capacities in terms of footprint and power supply available have to be checked against specific project power requirements.
EHTF fits production fields requiring high thermal insulation performance provided by Pipe-in-pipe (down to U-Value < 0.5W/m2.K). Thanks to its high efficiency, the system has low power requirement (typically below 50W/m). Therefore, it can also be an alternative to DEH when topsides capacities cannot meet footprint and power supply requirements. Pipeline heat tracing is a known technology for onshore plants and by extension applicable for subsea applications. The implementation of EHTF is completing qualification of this technology for deepwater applications.
HWC within bundle is a field proven technology. It fits production fields requiring high thermal insulation performance provided by bundle arrangement (down to U-Value < 0.5W/m2.K). The technology requires power and equipment to heat water thus impacting topsides space. These requirements vary considering project specific needs and selection of direct or indirect heating. For example, re-use of the produced water as an indirect heating medium can highly limit required power generation.
Quenot, C. (Technip.) | Carvalho, C. (Technip.) | Hanonge, D. (Technip.) | Fontes, F. (Technip.) | Beça, I. (Technip.) | Knapp, S. (Technip.) | Condessa, D. S. (Petrobras - Petróleo Brasileiro S.A.) | Damno, G. S. (Petrobras - Petróleo Brasileiro S.A.) | Gonçalves, W. P. (Petrobras - Petróleo Brasileiro S.A.)
The Papa Terra oil field is located on the BC-20 Block in the Campos Basin - Brazil (110 kilometers away from Rio de Janeiro state coast) in a water depth of 1,200 meters. The field is operated by Petrobras having Chevron as non-operator partner. Papa Terra has a crude oil with an API index between 14 and 17 degrees. The field is among one of the most complex subsea developments ever executed in Brazil with its first oil performed in 2013 and the production subsea facilities installation completed in 2014. The proposed design for the subsea production system was the use of an Electrically Trace Heated Integrated Production Bundle (ETH-IPB), the 3rd generation of this field proven technology, which was successfully designed, manufactured and installed by Technip on previous West African projects. A total of 27 km of ETH-IPB riser and flowline as well as its own electrical and monitoring module have been designed, manufactured, installed and successfully commissioned for the Papa Terra project. The core of the ETH-IPB is a 6" ID flexible pipe dedicated to production fluid.