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Steam generation for the purposes of thermal recovery includes facilities to treat the water (produced water or fresh water), generate the steam, and transport it to the injection wells. A steamflood uses high-quality steam injected into an oil reservoir. The quality of steam is defined as the weight percent of steam in the vapor phase to the total weight of steam. The higher the steam quality, the more heat is carried by this steam. High-quality steam provides heat to reduce oil viscosity, which mobilizes and sweeps the crude to the producing wells.
Typically, it is banded or clamped to the production tubing from below the wellhead to the ESP unit because it is not designed to support its own weight. It is a specially constructed three-phase power cable designed specifically for downhole well environments. The cable design must be small in diameter, protected from mechanical abuse, and impervious to physical and electrical deterioration because of aggressive well environments. They are available in a wide range of conductor sizes or gauges. They can be manufactured in either round or flat configurations, using several different insulation and metal armor materials for different hostile well environments.
The ESP motor is a two-pole, three-phase, squirrel cage, induction design. It operates on three-phase power at voltages as low as 230 and as high as 5,000, with amperages between 12 and 200. Generally, the length and diameter determines the motor's horsepower (HP) rating. Because the motor does not have the power cable running along its length, it can be manufactured in diameters slightly larger than the pumps and seal-chamber sections and still fit in the same casing bores. Typical diameters and rated HP ranges are shown in Table 1.
The Papa-Terra field in the Campos basin in Brazil is identified as having an oil interval of 14.6 API in turbidite sandstones. Because of the high-viscosity oil and low-API grade, innovative solutions and technological advances were incorporated into the project. The development uses an integrated production system consisting of a floating production, storage, and offloading (FPSO) vehicle connected to a tension-leg wellhead platform (TLWP) and dry completion wells. This allows the production of ultraheavy oil in deep water and enables rapid intervention for maintenance of electric submersible pumps (ESP). Because of the properties of the oil from the Papa-Terra field (high viscosity at low temperatures and low gas/oil ratio), the whole production development concept of the field was driven by artificial lift and flow-assurance requirements.
This paper presents an overview of the development of fire- and blast-resistant walls for offshore installations and introduces a fourth generation, or type, of wall. This thoroughly tested and certified type was developed as a response to the continual quest to further optimize the cost and weight of offshore topsides, thus allowing operators and designers to accommodate more equipment and higher field yield. The design of offshore installations is based on a variety of factors. This paper aims to explain dominant design preferences in the industry and review the key criteria that should be considered in order to optimize fire- and blast-resistant wall designs, with the hope that this may facilitate further wall optimization based on specific performance requirements. The intention of the paper is to provide the professionals who consider fire- and blast-wall designs for offshore installations with an objective viewpoint, allowing them to improve design for additional weight and cost savings.
As subsea electric lines age, they are prone to cracks that allow seawater in, reducing their effectiveness, and if the leaks are bad enough, they can shut down operations. A British subsea engineering and equipment company is selling a novel repair option that can be installed without ever going into the water. Viper Subsea's solution comes in the form of a box sending out specially programmed electrical signals. It has installed units on 17 umbilicals and subsea cables and it worked in all but two cases, said Max Nodder, business development director and cofounder of Viper, during a presentation at SPE Offshore Europe. For anyone whose mental image of insulation is a hard plastic shell isolating wires from the elements, Viper's method may seem farfetched.
DNV GL unveiled a methodology for managing safety and cost associated with corrosion under insulation (CUI) alongside new technology designed to support it. CUI occurs when water becomes trapped between insulation and the piping and vessels it is designed to protect. CUI contributed to more than 20% of all major oil and gas accidents in the EU over the past 35 years, according to DNV, in the form of localized external corrosion in carbon and low-alloy steels, external stress corrosion cracking, or pitting in austenitic and duplex stainless steel. Recommended Practice (RP) DNVGL RP G109, was developed with several regulatory bodies, international oil and gas operators, and others in the supply chain. DNV said the methodology helps integrity engineers and plant managers identify areas with the greatest current and future risk of CUI and take action to prevent failures.
A consortium of organizations has set out to tackle one of the more enduring challenges in the North Sea: the nondestructive testing (NDT) of corroded pipes under insulation and engineered temporary pipe wraps. The group--which includes TRAC Oil & Gas; the University of Strathclyde; and CENSIS, the Scottish Innovation Centre for Sensor and Imaging Systems--will methodically audit the tools, capabilities, and approaches currently used by industry to look at the steel surfaces of assets often obstructed by layers of material. While there are several NDT technologies on the market, many are ineffective when used on pipes that are protected by insulation. They tend to average out wall thickness where corrosion scabs have formed, failing to pinpoint specific areas of vulnerability. Taking and interpreting these readings is further complicated by the varying dimensions, materials, locations, and accessibility of different oil and gas assets.
This paper describes both design and economic considerations that lead to the selection of vacuum-insulated tubing (VIT) or vacuum-insulated casing (VIC) for the completion of thermal wells. The results shared in this paper are some of the parameters considered during thermal-well design: temperature on the casing and the tubing, and heat loss. Knowing these parameters, well integrity can be studied and the overall efficiency of the process estimated. The most common thermal enhanced-recovery methods are cyclic steam stimulation, steamflooding, and steam-assisted gravity drainage, which is widely used in Canada. The role of these thermal-recovery methods is to convey heat into the reservoir, mainly by convection.
In the summer 2015, Nikhil Joshi, an experienced chemical engineer, and a small integrated team which included subsurface, facilities and flow assurance personnel were faced with a task. They had to look at design simplifications for a brownfield subsea tieback (including flow assurance front-end engineering design) to enable an investment decision. What was different about this project, however, was that they had only 3 months to complete the task. During an SPE Flow Assurance Technical Section presentation, Joshi, a director for Moulinex Energy, presented a case study "Getting to Sanction in 3 Months--Engineering Perspective," which detailed how he and his team enabled an investment decision with partner approval. "My general manager said, 'I have a great project I want to go forward with'. His mind was made up, but he wanted assurance from flow assurance people," Joshi said.