Leonard LeBlanc
Houston
Electronic sensing of wellhead pressure under development
Steel exposed to changes in pressure reacts by taking on different magnetic properties. This is the principle upon which the development of the non-intrusive wellhead pressure measurement device is based.
ABB Vetco Gray and ABB Corporate Research are preparing to introduce the non-intrusive pressure sensor which eliminates the drilling of holes in the wellhead to insert measurement instruments. The device permits easy mounting, calibration, and transmission of pressure information from subsea wellheads to surface platforms.
Composite anode tests indicate 30% reduction in weight and cost
A new sacrificial anode made of aluminum alloy with a magnesium alloy skin has produced a 30% reduction in cost and weight in early testing. Much of the cost reduction is a product of the protective calcareous deposits formed quickly on the cathodic structure.
The anodes were developed by Agip Offshore and Tecnomare and are being tested in the Garibalde D and Daria platforms in the Adriatic Sea. Special casting parameters have been developed to optimize the adhesion and chemical properties at the interface between the two materials.
The calcareous coating acts as a dielectric coating reducing current requirements for protection. This anode supplies high peak current required to produce an effective layer of protective deposits, while minimizing the size of the anode structure.
Valve uses choke flow to eliminate moving parts
The nuclear power uses a vortex to choke down or cut off flow in a valve, a principle that eliminates all moving parts within the valve body. The technology is being used to develop a similar type wellhead choke valve for the petroleum industry in order to control erosive mixtures of sand, oil, gas, and water. The development is being undertaken by Liverpool University, AEA Technology, Total, BP, Amerada Hess, Texaco, and the British OSO.
The valve operates at full open flow by allowing product flow into a thin circular chamber from a radius supply port. The flow exhausts the valve directly through an axial port. Control begins with injection of a small flow from a tangential port. This spirals the product flow from the supply port, creating a radial pressure gradient across the chamber. This step increases resistance to the flow. Production flow will cease completely as soon as flow from the tangential port reaches 10-15% of the production flow.
Low-cost skid-mounted syncrude plant designed for remote locations
A skid-mounted natural gas conversion plant has been designed by DCA Consultants of Britain to deal with associated gas on locations where it cannot be flared or inexpensively re-injected into the reservoir. The modular unit can accommodate 2-200 MMcf/d and can be mounted on platforms and vessels.
The system can be adjusted to output syncrude (45°-65° gravity), syncrude plus LPG, syncrude plus diesel, syncrude plus electricity, syncrude plus diesel and electricity, paraffinic wax, and methanol. The product mix can be changed while the plant is in operation. The methanol output change will require a slightly longer period for refit and additional storage.
The system consists of three modules: partial oxidation plant, oxygen plant, and Fischer Tropsch plant. Excess energy from the plant can be used for refining or blending with crude oil.
Reference: Antia, D., Seddon, D., "Offshore Conversion of Associated Gas to Synthetic Crude Oil: An Economic Option for Deepwater and Marginal Fields, OTC 7868. May, 1995.
New developments in Electronics, software:
- Reservoir coupling: Interra (Abingdon, Oxfordshire, UK) Norsk Hydro, and Statoil have developed a simplified way of modeling the joining of independent reservoirs through common surface facilities.
- 3D volumes: CogniSeis Development of Houston has created a program that allows a user to conduct sub-volume detection on a trace inverted volume and extracting the reservoir interval to analyze.
- Seakeeping power: The Maritime Research Institute of Wageningen, The Netherlands has developed a program to idealize power needs and predict seakeeping behavior for surface effect ships and planing craft.
- Shear wave logs: Halliburton Energy Services of Houston has developed a dipole sonic logging system that provides shear wave logging in unconsolidated formations.
- Process engineering: Desktop PC inspection of processing information has been developed by Setpoint of Houston to provide charting of historical data from multiple measurements.
- Map conversion: A system that converts paper and raster maps into digital data for geological databases has been developed by Neuralog of Houston.
- Video bid walking: A method of producing videotapes of facilities, including CAD drawings, text, charts, animation, and audio to illustrate project modifications to be done has been developed by EDG of New Orleans. The process eliminates walk-throughs of offshore facilities.
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