Abstract: A composition suitable for use in a packer element for a wellbore includes: a hydrocarbon-swellable polymer, the hydrocarbon-swellable polymer present in the composition in an amount between about 10 and 30 percent by weight; an oil-resistant polymer, the oil-resistant polymer present in the composition in an amount between about 10 and 30 percent by weight; and a hydrocarbon swelling agent, the hydrocarbon swelling agent present in the composition in an amount between about 15 and 60 percent by weight. A composition as described may have a good balance of the swelling properties of the hydrocarbon-swellable polymer and the mechanical properties of the oil-resistant polymer. These properties may be useful in a packer element for a wellbore.

Abstract: A composition suitable for use in a packer element for a wellbore includes: a hydrocarbon-swellable polymer, the hydrocarbon-swellable polymer present in the composition in an amount between about 10 and 30 percent by weight; an oil-resistant polymer, the oil-resistant polymer present in the composition in an amount between about 10 and 30 percent by weight; and a hydrocarbon swelling agent, the hydrocarbon swelling agent present in the composition in an amount between about 15 and 60 percent by weight. A composition as described may have a good balance of the swelling properties of the hydrocarbon-swellable polymer and the mechanical properties of the oil-resistant polymer. These properties may be useful in a packer element for a wellbore.

Abstract: A packer system for a wellbore includes a tubular member and a packer element having an inner layer that circumferentially overlies the tubular member and an outer layer that circumferentially overlies the inner layer. The inner layer includes an elastomer that swells upon contact with a swelling fluid. The outer layer includes a material that provides at least a partial barrier to the swelling fluid.

Abstract: High-critical-temperature superconducting materials produce a magnetic field which acts as an electric field insulation, and as a substitute for dielectrics, so as to store high electrical voltage and high electrical energy, thereby eliminating the need of insulating dielectrics capacitors so as to make the energy source light and compact, and very suitable for storage of electrical energy, as a one-stage electron accelerator and/or for pulsed power applications.

Abstract: High T.sub.c superconductor quantum interferometric devices are disclosed. Such devices are especially suited for detecting small changes and spatial variation in magnetic field. Such detection finds important application in NDE evaluation of metals, in the evaulation of magnetic susceptibilities and in magnetic resonance spectrometers.

Abstract: High-T.sub.c superconductor quantum interference devices (SQUIDs) for noise-free, accurate measurements of defects and flaws in metal shapes and forms by measuring changes in the secondary magnetic field intensity around any point which is excited by a primary excitation current or by measuring changes in the impedance of the exciting coils. These measured changes are correlated to defects and flaws present in the metal.