Abstract: A well system can include a drill string having a drill bit at an end thereof, and a swellable seal exposed to fluid in an annulus external to the drill string. The swellable seal can include a swellable material which swells in response to the fluid comprising a predetermined activating agent. A method of preventing undesired release of fluid from a wellbore can include displacing a drill string through the wellbore, thereby drilling the wellbore, and installing in the wellbore a swellable seal which, in response to the fluid comprising a predetermined activating agent, reduces flow through an annulus formed radially between the drill string and the wellbore. Another well system can include a swellable seal carried into a wellbore on a drill string, with the swellable seal including a swellable material which swells in response to a fluid in the wellbore comprising a predetermined activating agent.

Abstract: A well system can include a drill string having a drill bit at an end thereof, and a swellable seal exposed to fluid in an annulus external to the drill string. The swellable seal can include a swellable material which swells in response to the fluid comprising a predetermined activating agent. A method of preventing undesired release of fluid from a wellbore can include displacing a drill string through the wellbore, thereby drilling the wellbore, and installing in the wellbore a swellable seal which, in response to the fluid comprising a predetermined activating agent, reduces flow through an annulus formed radially between the drill string and the wellbore. Another well system can include a swellable seal carried into a wellbore on a drill string, with the swellable seal including a swellable material which swells in response to a fluid in the wellbore comprising a predetermined activating agent.

Abstract: Systems and methods for determining olefin concentrations in olefin-containing fuels (e.g., gasoline) are described. Generally, a Raman spectrum from a linear-calibration reference sample (e.g., a pure hydrocarbon, such as toluene) and Raman spectra from multiple simulated fuel samples having known olefin concentrations are obtained. An area ratio for each simulated fuel sample is created by dividing the area in the olefin region of each fuel sample by the area in the chemical spectral region of the linear-calibration reference sample. The area ratio and the known olefin concentration for each simulated sample are used to create a linear olefin calibration. The olefin concentration of a fuel sample with an unknown olefin concentration is calculated by determining the area ratio between the olefin spectral region in the unknown sample and the chemical spectral region in a concentration-calculation reference sample (e.g., toluene) and placing the new area ratio into the linear olefin calibration.

Abstract: An optical fiber multiplexer having a fixed plate and a rotating plate. A plurality of fiber-optic channels are coupled to the fixed plate in a circumferential arrangement. One fiber-optic channel is coupled to the rotating plate. Each fiber-optic channel may include one or more separate optical fibers. A servo motor rotates the rotating plate. Switching between channels occurs by rotating the rotating plate and aligning the optical fibers on the fixed plate and the rotating plate. Lens-to-lens coupling is used to transmit optical signals between the rotating and fixed plates. An adjustment device, such as a gimbal mount, may be used to adjust the horizontal and vertical axial alignment of the optical fibers coupled to the fixed plate so that optimum light signal transmission can occur. A control unit controls the operation of the servo motor.

Abstract: A plastic canister for storing and shipping drill bits, especially roller cone drill bit, has a pin-holder built into the lid of the canister for ease of field dressing the bit. The lid and body of the container are slip fit to one another and indexed to each other for positive positioning in their relationship. Safety features include the use of a conductive plastic polymer, a non-rolling base, mating protrusions and recesses for stacking, recessed areas for strapping, and welded loop handles.

Abstract: A plastic canister for storing and shipping drill bits, especially roller cone drill bit, has a pin-holder built into the lid of the canister for ease of field dressing the bit. The lid and body of the container are slip fit to one another and indexed to each other for positive positioning in their relationship. Safety features include the use of a conductive plastic polymer, a non-rolling base, mating protrusions and recesses for stacking, recessed areas for strapping, and welded loop handles.

Abstract: Raman spectrometer for analyzing the chemical composition of sample streams using an external cavity laser light source is disclosed. The laser provides an effective light source useful in continuously analyzing a sample stream containing petroleum products, aqueous or biological fluids, or solid slurries. The light is introduced into a bundle of optical fibers connected to a Raman sample cell. The Raman sample cell is configured to allow continuous sample flow therethrough. Scattered light from the sample cell preferably exits the optical fibers as a linear optical signal. A Raman spectrometer passes the optical signal through an excitation wavelength filter, an optical slit, and a volume holographic transmission grating with an aberration correction device before transmitting the optical signal to a charge coupled device array which converts the optical signal into a electronic signal.

Abstract: A spectrograph for analyzing the chemical composition of a sample is disclosed. Scattered light from a sample cell is collected by one or more optical fibers and is introduced into a collimating lens as a linear optical signal. The collimating lens directs the optical signal to a reflective diffraction grating which reflects the signal into a focusing lens. The focusing lens focuses the optical signal onto a charge coupled device array which converts the optical signal into a electronic signal. Aberration correction is provided by the collimating and focussing lenses. The electronic signal is analyzed and converted by computer into a representation of the chemical analysis of the sample stream.

Abstract: Apparatus and methods for analyzing the chemical composition of fluid streams using Raman spectroscopy are disclosed. The invention is particularly useful in continuously analyzing a fluid stream containing petroleum products, aqueous or biological fluids. The apparatus includes a laser source for producing light having an excitation wavelength. The light is introduced into a bundle of optical fibers connected to a tubular Raman enhancement cell. A transparent optical element (lens and/or window) acts as a barrier element to isolate the flowing sample stream from the optical components. The Raman enhancement cell is configured to allow continuous sample fluid flow therethrough, and it is preferably lined with a material having an index of refraction less than the index of refraction of the fluid stream. Scattered light from the enhancement cell preferably exits the optical fibers as a linear optical signal.

Abstract: A centralizing tool for use in drilling an earth borehole. Drilling fluid pressure extends contact members radially from the tool into engagement with the borehole walls. A timing wheel engages each of the contact members to coordinate their radial movement. A fluid driven tubular central piston extending through the timing wheel causes the wheel to rotate as the piston is moved axially through the tool. High fluid pressure drives the contact members radially outwardly and moves the piston axially to compress a central coil spring surrounding the piston. Reduction of the drilling fluid pressure allows the spring force to return the piston to its initial axial position which rotates the timing wheel to retract the contact elements.

Abstract: Surfaces of hydrophobic polymers are treated to reduce their friction resistance characteristics when in contact with an aqueous environment by exposing the surfaces to an oxidation treatment, preferably by use of radio frequency glow discharge. This oxidation is followed by exposure to atmospheric air, until there is a substantial reduction in the air-water contact angle of the surfaces. The reduced friction resistance characteristics are important in aqueous applications where there is movement between the surfaces of two polymeric materials, such as in double slideable catheters and similar medical products. This process also provides lower coefficients of friction for general polymeric products in contact with water and aqueous solutions.