Seismic monitoring is bringing reservoir operators new information about fluid movement. Two different methods—4D seismic and micro-seismic monitoring—are emerging as promising techniques that use seismic energy to map fluid fronts. With field examples, we illustrate the power of these methods and discuss the potential of permanent sensors for seismic surveillance.
Harmful drilling vibrations are costing the industry dearly. This article explains the three main vibration types—axial, torsional and transverse—and what causes them. Technology exists to eliminate most vibrations, but requires more systematic deployment than is usual. Hardware that eliminates vibrations is reviewed, including downhole shock measurement, torque feedback shock guards and antiwhirl bits.
Downhole formation fluid sampling would be much simpler if we could see the fluid in the formation before deciding whether or not to take a sample of it. Optical analysis provides the eyes to reveal oil, water or gas as fluid is pumped from the formation. This not only allows sampling when the desired fluid is present, but can provide zone-by-zone details of formation fluid. We look at the development of formation sampling and how optical analysis works.
Traditional methods of evaluating fluid saturation behind casing are limited to either high-salinity water or nontubing wells. The RST Reservoir Saturation Tool overcomes these limitations by combining both thermal decay time and carbon oxygen logging in a tool slim enough to log through tubing.
Over the past few years, exploration tools have evolved at a quickening pace, changing how explorationists think about prospects. Advances in 3D seismic, reservoir characterization, geochemistry and drilling techniques are making formerly uneconomic prospects attractive. Overall, prospect analysis is embracing a wider scope of disciplines. A group of leading geoscientists shares their views on how changes in the technology of exploration are redirecting the search for hydrocarbons.
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