Abstract: An optical binary signal geophone is described. The geophone utilizes an optical fiber for the transmission of light to the geophone. The geophone contains a light chopping means which oscillates in response to vibrations imparted into a geologic formation. As the chopping means such as a baffle or a tubular member vibrates, it chops the light signal and creates an on/off light pattern. The light passing through a slit in the baffle or tubular member is returned to the seismic vehicle for further processing. The optical geophone creates a binary signal directly without the use of clipping electronics and magnets or coils used in conventional geophones.

Abstract: A method and means for determining the amount of stretch in a well logging cable is disclosed. An optical fiber is run into a well with a logging cable and looped back to the surface. A second optical fiber of nominal length is maintained on the surface. A source of monochromatic light is passed through both fibers and recombined. As the well logging tool is raised and lowered in the wellbore, the number of interference fringes passing a fixed point is determined. The change in length of the optical fiber and, therefore, the cable will be equal to 1/2 the number of interference fringes passing a fixed point times the wavelength of light used. A precise determination of vertical location can then be made when this information is combined with information from a surface mounted odometer or encoder. This information further allows a precise determination of interval bulk density or other formation parameters in which it is important to know the depth of a tool.

Abstract: A method and apparatus for determining the vertical location of a logging tool in a wellbore is disclosed. An electrical signal is transmitted through a conductor in a well logging cable and a second conductor in the surface. Change in length of the well logging cable is determined by monitoring phase changes in the signals from the first and second conductors.

Abstract: A method and means for determining the amount of stretch in a well logging cable is disclosed. An optical fiber is run into a well with a logging cable and looped back to the surface. A second optical fiber of nominal length is maintained on the surface. A source of monochromatic light is passed through both fibers and recombined. As the well logging tool is raised and lowered in the wellbore, the number of interference fringes passing a fixed point is determined. The change in length of the optical fiber and, therefore, the cable will be equal to 1/2 the number of interference fringes passing a fixed point times the wavelength of light used. A precise determination of vertical location can then be made when this information is combined with information from a surface mounted odometer or encoder. This information further allows a precise determination of interval bulk density or other formation parameters in which it is important to know the depth of a tool.

Abstract: An optical-electrical geophone which generates a binary signal is described. The geophone utilizes an optical fiber for the return transmission of a light source in the geophone. The geophone contains a light chopping means which oscillates in response to vibrations imparted into a geologic formation. As the chopping means such as a baffle or a tubular member vibrates, it chops the light signal and creates an on/off light pattern, i.e., binary signal. The light passing through a slit in the baffle or tubular member is returned to the seismic vehicle through an optical fiber for further processing. The optical-electrical geophone creates a binary signal directly without the use of clipping electronics and magnets or coils used in conventional geophones.

Abstract: In accordance with the present invention, a marine streamer test system and method (MARSTEST) is disclosed for testing field-worthiness of hydrophone sections within the streamer under both passive and dynamic operating conditions. With regard to a passive operating state, five (5) test parameters are automatically generated and compared with upper and lower limits stored within a mini-computer housed aboard the marine exploration boat. Any out-of-specification values trip an alarm network and a printer to warn of the malfunctioning streamer section. Result: replacement or other repair can be effected. With regard to dynamic operating conditions, acceptable "signature" characteristics of the streamer (such characteristics can be 2 or more of the above 5 parameters) are stored within the computer aboard the exploration boat and are compared with actually generated field parameter values acquired during operations, say between "shots", i.e.