Risk Factors in Oil and Gas Well Electronics Compared to Other Electronic Industries

Risk Factors in Oil and Gas Well Electronics Compared to Other Electronic Industries — The oil and gas well electronics industry is a low volume industry in which the development and the operating life cycles of the electronic products used is considerably longer than those of the commonly available commercial parts used to build them. Oil and gas well electronic systems, especially the ones that are used for permanent monitoring of oil wells are required to function reliably at all times throughout the entire life of an oilwell. This gives rise to special requirements for the electronics used in this industry. Guaranteed reliability under high stress operating requirements over longer life cycle profiles necessitates the use of special design, qualification and testing techniques and quality controls. All these factors create considerable risks for the suppliers and manufacturers of oil and gas well electronics. This paper presents a study of the factors that lead to risks, which manufacturers and suppliers of oil and gas well electronics must address while developing products for use in the well completion and continuous monitoring operations. A comparison with other low-volume electronic industries is provided. Oil & Gas Science and Technology – Rev. IFP, Vol. 60 (2005), No. 4 1 OIL AND GAS EQUIPMENT ELECTRONICS Electronic products are essential in all aspects of oil and gas exploration, development and production, from the petroleum reservoir, to transport, and to the refinery, where it is transformed into fuels and other chemical products [1]. A hydrocarbon reservoir life-cycle chronologically consists of exploration, discovery, extended well test, appraisal, field development, production plateau, and production decline [2]. Figure 1 shows a time line for an oil and gas well depicting the use of electronic technologies. The measurement of one or more physical quantities in or around the well is called well logging, with the word “log” used in the sense of a record. Well testing provides access to and measurement of dynamic reservoir data—including pressure, temperature, and fluid properties—while the well is either flowing or shut in. Well completion is the work conducted on a wellbore to establish safe production of the resource (i.e., oil and gas) after the production casing string1 has been set. Based on the operations along the time line, the four major applications of electronic products in the oil and gas industry are: • Oil and gas exploration: Electronic technologies are used extensively in turning untapped resources into recoverable reserves by acquiring an understanding of the architecture and fluid flow behavior of the reservoir. Initial geologic information from seismic surveys, well-logs, productivity tests, and other remote sensing techniques such as gravimetric, radiometric and electromagnetic sensing, are used 1 A long section of connected pipe that is lowered into a wellbore and cemented to provide strength for installation of wellhead equipment, to seal off leaky, low strength or fractured formations, and to seal off high-pressure zones so that lower pressure formations may be drilled with lower drilling fluid densities [3]. to evaluate reservoir boundaries, estimate reserves, plan drilling programs, and design surface facilities. • Data acquisition technologies: Data acquisition technologies compile and integrate the reservoir data including geologic, seismic, well log, well test, pressure, rock, fluid and interpretative data. Data interpretation, geological modeling, reservoir simulation and production analysis help to create field depletion scenarios and reservoir development strategies [2]. These are used to find how much oil or gas is there, how much is recoverable, how fast it can be recovered, how much capital expenditure is required, and what will be the return on investment [4]. • Sensor technologies: Sensors are used to identify the reservoir rock and any fluids contained therein by measuring their physical properties. The physical properties used are resistivity (oil has high resistivity, salt water has low resistivity), radioactivity (gamma ray detector), acoustic impedance, pressure, density, temperature and temperature gradient. Measurement of these properties enables the improvement of oilwell effectiveness. • Permanent monitoring and control systems: Permanent monitoring systems measure and record well performance and reservoir behavior in real time, 24 h a day, throughout the lifetime of the reservoir. This information can be used by engineers to dynamically manage hydrocarbon assets, to update reservoir models, to optimize production techniques, and diagnose problems so that remedial treatments and field development strategies can be refined or adjusted [1]. Permanent downhole gauge (PDG) systems are widely used for horizontal and multi-lateral wells, as an alternative to wireline conveyed downhole surveys used traditionally for vertical wells [5]. Gauges collect data useful for both shortterm troubleshooting and long-term development planning. Downhole measurements include temperature, pressure, 722