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Technology Applications

Subsea Tapping Machine

The TDW Subsea 1200RC Tapping Machine (Fig. 1) is a remotely ­controlled subsea hot-tap system. It is controlled by an operator with a laptop aboard a diving-support vessel or platform. This machine dramatically reduces dependence upon divers, making the process safer. Because this system reduces dependence upon divers, hot tapping can be carried out in water to a depth of 3000 m. The machine also can be used in shallow situations where divers could not previously operate. The operator has a view of the operation on a screen, providing the ability to make more-rapid better-informed decisions. The machine is self-contained, with a built-in hydraulic and control system that is topside-driven with a passive remotely-operated-vehicle (ROV) interface (i.e., a stationary ROV with its hydraulics and control system attached to the tapping machine). The hydraulic and electronic power can be supplied by standard work-class ROVs or by other subsea hydraulic-power units with similar properties. The ROV provides hydraulic power (closed loop) to engage a motor/pump unit on the  tapping-machine frame. The motor/pump unit sends hydraulics through a valve pack to the appropriate motor / hydraulic function. Electrical power for various control and ancillary functions is supplied by the ROV through an umbilical feed.

Increasing Multizone Efficiency

Traditional ball-drop systems for multizone hydraulic-fracturing operations require deployment of balls and ball seats of successively smaller sizes, moving from heel to toe of a lateral. This process may require increased surface pressure and pumping horsepower to continue the necessary flow rate. Operators compensate by deploying additional casing and pumping larger volumes of proppant. Weatherford’s i-Ball Multizone Fracturing System (Fig. 2), which can be run as part of the ZoneSelect system, eliminates downhole-pressure buildup and associated logistics and storage concerns with the use of a single ball-and-seat size. The diameter of the system (close to that of the tubing) enables an unlimited number of zones to be stimulated, and the zones are fracture stimulated one at a time. Then, the sleeves retract to a size that is close to the inside diameter (ID) of the host tubing. This action reduces frictional force, enables a more-efficient fracture at each zone, allows for a smaller-ID fracturing string, and, in some cases, facilitates fracturing operations through the completion. The technology has been tested in openhole and cemented wellbores and is rated to 10,000 psi with a temperature envelope of 32 to 350°F. It is highly tolerant of downhole debris, such as lost-control material and fracturing sand and proppant. In April of this year, 400 of these sleeves will be run between four operators, running an average of 30 sleeves per well.

Casing to Target Depth

Two conventional attempts to run a 7-in. liner to total depth (TD) in a Norwegian North Sea well had been unsuccessful, with the liner hanging up hundreds of meters from TD. The problem was caused by borehole instability and severe washout in the weak shales, coals, and notorious paleosols of the area. A sidetrack was drilled successfully, and the liner was run with Deep Casing Tools’ Turbocaser Express as a contingency against wellbore obstructions. The system is a high-speed drillable reaming system that enables drilling teams to land casings and intermediate liners at target depth on the first attempt. If hole conditions prove too severe, the full-bore rapid-drill-through capability of the tool would allow the remaining reservoir to be accessed. The 7-in. liner was run and, as predicted, stopped with 10 t total weight at 4117 m (1260 m from TD), where the liner could not be rotated or run deeper. Circulation was established, and the reaming system was used to clear the obstruction. The next obstruction was at 4378 m, where the tool was used again to ream. This process was repeated most of the way to TD. Total reaming time was 21 hours, at an average rate of 60 m/h.

Programmed Variable-Speed Drive

WEG has launched a new range of inverter drives that provide exceptional performance for three-phase induction-motor control. The CFW500 inverter drives (Fig. 3) have power ratings from 0.18 to 22 kW. The drives are based on modular plug-and-play design. The drive includes a built-in programmable-­logic controller—a micro-PLC—that can be programmed according to standard protocol, International Electrotechnical Commission 61131-3. It also comes with preprogrammed macros for a range of applications (e.g., positioning, timer, and acceleration). Users can program the drive by use of the built-in display, or by a computer through a variety of interfaces. The drives can identify up to 64 different plug-in modules for supporting decentralized automation concepts, and they are easy to connect to all the major fieldbus systems. The drive uses expansion plug-in modules, which makes it easy to customize even for bespoke applications. The system provides an indication of up to three simultaneous variables, such as speed and performance statistics of the inverter. The inverter drives can operate in ambient temperatures up to 50°C.

Pile-Guiding Tool

IHC Handling Systems, part of IHC Merwede, delivered a pile-guiding tool for installing 80 wind-turbine foundations at the Meerwind offshore wind-farm project in the German North Sea. The pile-guiding tool is part of an extensive package of handling and lifting equipment for the project. The package included a 700-t upending tool (Fig. 4) and the accompanying hydraulic-power packs. The windmill-­foundation monopiles are lifted and positioned by the equipment more efficiently than previous methods. The foundation of these wind turbines consists of a monopile and a transition piece. The monopiles have an outer diameter of 5.500 m, an overall length of 64 m, and a maximum weight of 680 t. The transition piece connects the monopile to the mast of the wind turbine. The new pile-guiding tool replaced the commonly used upending bucket and guiding-and-positioning tool by combining two operations—tilting and positioning—into one piece of equipment. In doing so, it saves time during the installation process. In addition, less deck space is required and the tool is much lighter than previous equipment.

Oilfield Antiscalant

BWA offers its Bellasol oilfield antiscalant product line (Fig. 5) that meets Centre for Environment, Fisheries & Aquaculture Science standards. The suite of products includes a biodegradable antiscalant (68% in 28 days per the Organisation for Economic Co-­operation and Development Test 306) that is hydrothermally stable to 180°C, is compatible with biocides and other oilfield additives, and outperforms traditional biodegradable scale-control chemistries such as polyaspartate for inhibition of barium sulfate, calcium carbonate, and mixed scales. The company has also launched its Bellacide 350, a biocide that is highly effective at controlling sulfate-reducing bacteria that can introduce hydrogen sulfide and lead to souring. The biocide active is one of the first new biocidal actives approved by the US Environmental Protection Agency in nearly a decade. Unlike glutaraldehyde or glutaraldehyde blends typically used in the oil/gas industry, this biocide helps minimize health and safety risks because it is not classified as a skin sensitizer, is not a human carcinogen, and does not present inhalation hazards. This biocide is used in many US hydraulic-fracturing operations, where health and safety are increasingly important.

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High-Pressure Switches

Honeywell has introduced its High-Pressure-Premium, HPS Series Pressure Switches (Fig. 6) that have a 2,000,000 life-cycle rating, environmental sealing, and multiple-port and termination options. The electromechanical-gauge pressure-on/-off switches are designed for use in applications that require the making or breaking of an electrical connection in response to a pressure change of the system media. The switches have a wide pressure-switching-point range of 150 to 4,500 psi, a proof-pressure-rating of 10,000 psi, and burst-pressure rating of 20,000 psi. The sealing rating ensures media ingress will not create switch failure—useful in applications where the switch is splashed with fluid or is temporarily immersed. The switches are compatible with a variety of media including petroleum-based hydraulic fluids, pressurized air, water, and mineral-oil-based brake fluid. An operating temperature range of −40 to 248°F enables use in a variety of environments. These switches have a switching-point accuracy of up to ±2%. Their switching capability of 5 mA to 5 A allows use in a wide range of applications, from heavy loads to those connected to an electronic control unit.