Abstract: Apparatus to generate electricity from energy in a flowing stream of fluid comprises a piezoelectric member and a flow restrictor connected with the member to cause portions of a flowing stream of fluid to flow past different sides of the member such that the member deforms to generate electricity in response thereto. A particular such apparatus includes a conduit to conduct a flowing stream of fluid; a divider disposed along at least a portion of the length of the conduit such that the divider divides that portion of the conduit into two flow channels; a piezoelectric member connected to the divider such that one side of the piezoelectric member is exposed to one of the two flow channels and another side of the piezoelectric member is exposed to the other of the two flow channels; and a flow restrictor disposed at a location between one end of the divider and the other end of the divider.

Abstract: The present invention provides improved traceable well cement compositions and methods. The compositions are basically comprised of hydraulic cement, sufficient water to form a pumpable slurry and a normally non-radioactive tracer compound which becomes radioactive and emits detectible rays over a relatively short time period when exposed to neutrons. The methods of the invention relate to cementing a zone in a well and subsequently detecting the subterranean location of the cement composition therein. A traceable well cement composition of the invention is formed and introduced into a subterranean zone to be cemented. Neutrons are then emitted from a source in the well so that the tracer compound emits detectible rays, the rays are detected and the location of the cement composition in the well is determined.

Abstract: An intelligent automatic gain stabilization method and apparatus for a radiation detection instrument automatically locate the position of a predetermined characteristic within an energy spectrum, automatically determine whether the characteristic is properly located, and automatically provide gain adjustment to the output of the radiation detection instrument to maintain measurement accuracy of the system.

Abstract: A method of evaluating a gravel pack slurry uses a fast neutron source and a thermal neutron detector to produce responses from which gravel settling rate, packing efficiency, gravel concentration, porosity and density can be determined. The method can be applied to either static or dynamic slurries in either a laboratory test environment or an actual well environment.

Abstract: An apparatus and method utilize a neutron sensitive medium in which initially existing atoms of the medium are divided into particles, reaction energy and neutron energy. The medium undergoes polarization in response to the reaction energy and the neutron energy. This produces an electrical charge gradient which is proportional to the energies and which can be sensed and analyzed to indicate just the neutron energy.

Abstract: A vessel for receiving a test sample of fluid whose water content is to be determined and a thermal neutron sensor are retained in cavities of a biological radioactivity shield. The cavities are lined with a material which blocks external thermal neutrons outside the test sample from being detected by the thermal neutron sensor. Another cavity, having an inner end terminated by the lining material, receives a source of fast neutrons which are to be emitted through the liner into the test sample to become thermal neutrons if they interact with hydrogen within the test sample. The latter thermal neutrons which are backscattered to the sensor are detected, and in response an electrical signal encoded to represent the count of detected thermal neutrons is generated to indicate a measure of the water content of the test sample.

Abstract: A downhole tool for an oil or gas well includes a self-contained power supply having a housing in which a primary fuel source, a Stirling cycle engine, and a linear alternator are disposed. The primary fuel source includes a radioisotope which, by its radioactive decay, provides heat to operate the Stirling engine which in turn drives the liner alternator to provide a suitable electrical output for use by the circuit of the downhole tool.