Abstract: A compliant offshore structure in which the primary restoring force to lateral displacement is provided by elongate flex elements. A gravity base is rigidly secured to the ocean bottom. A tower extends vertically upward from the base to a position above the ocean surface. A work deck is supported atop the tower. The tower is secured to the base by elongate flex elements which are arranged in an array surrounding the central axis of the structure. Each flex element has one end secured to the base and a second end secured to the tower. The flex elements permit the tower to pivot about its lower end, thus providing the tower and deck with a compliant response to environmental forces. The flex elements also support the tower above and free from contact with the base. This eliminates the need for a vertical load bearing joint between the tower and base.

Abstract: A method for restoring to filtered seismic data at least some of the ramdom background noise associated with the data in its form prior to filtering. The method includes the steps of filtering seismic data in a two-dimensional filter; generating a noise signal representing the random background noise associated with the data; filtering the noise signal in an inverse filter corresponding to the two-dimensional filter; and adding the inverse-filtered first signal to the filtered seismic data. In one embodiment, the noise signal is generated by filtering a copy of the data in a least-mean-squares adaptive filter to remove substantially all coherent energy therefrom. In another embodiment, the noise signal is an independently generated white noise signal having beginning and end times matching those of the seismic data. This white noise signal is the bandpass filtered to cause its frequency content to match that of the seismic data.

Abstract: A system for supporting one end of a riser or other elongate element from a marine structure. In the preferred embodiment, a plurality of gas springs are symmetrically disposed about the upper end of a riser. The axis of compression of each gas spring is parallel to the axis of the riser. One end of each gas spring is secured to the riser and the other end of each gas spring is secured to the marine structure. Relative motion between the riser and marine structure along the riser axis is accommodated by contraction or extension of the gas springs. A gas reservoir can be provided to reduce pressure changes as the gas springs extend and contract. This reduces changes in the loading applied to the riser as the marine structure moves relative to the ocean bottom.

Abstract: A method and apparatus for selectively controlling isolated distributed recorders in an Isolated Distributed Recording System. Selection and control of isolated distributed recording units comprising a seismic data gathering Isolated Distributed Recording System are effected by transmitting preselected encoded acoustic seismic signals to which the isolated distributed recorders have been preconditioned to respond by effecting a desired control action. The same encoded acoustic seismic signal may also provide the seismic data for the experiment. Each isolated distributed recorder is conditioned to respond to several encoded acoustic signals, to discriminate against noise, and/or to respond to one such encoded acoustic signal by effecting a plurality of control actions at the isolated distributed recorder.

Abstract: A 3-D radial seismic survey method is described suitable for accurately defining by migration processing an area having a dome-like subsurface structure. Radial survey lines are plotted with polar symmetry with respect to a center position at the center of the dome, such lines traversing the steep dip in all directions at approximate right angles. Hence, the developed data is efficiently acquired data useful for defining the structure. Bisecting survey lines may be provided as the original lines diverge to satisfy sampling requirements for migration. Data is acquired and sorted into bins that are annulus sectors and which are maintained sufficiently uniform in size to be within a maximum-to-minimum ratio of 2-to-1. Seismic source and receiver lines may be coincident or angularly offset.

Abstract: The present invention utilizes a gravity influenced liquid distribution within a substantially horizontal header which receives a liquid-vapor mixture in annular flow from a supply line and divides that single stream into multiple streams, each flowing through a branchline to deliver substantially uniform quality liquid-vapor mixture to a nearby site. The header is substantially horizontal and each branchline is connected to the periphery of the header further downstream and relatively lower on the periphery of the header than the preceding branchline.

Abstract: A drill pipe protector which surrounds and embraces a section of drill pipe. The protector includes at least an outer portion and surface made of an elastomeric material in which a quantity of small, hard particles are interspersed. During drilling operations when the protector is placed in sliding contact with the interior surface of casing in a wellbore, the particles exposed on the protectors surface abrade away rust and other protrusions from the inner surface of the casing to rapidly reduce frictional torque and drag experienced in running the drill string. As particles and elastomer are abraded away, additional particles are exposed. In the preferred embodiment the protector is a sleeve consisting of a pair of semi-cylindrical sections, each having an outer elastomeric layer containing approximately 27% by volume and 43% of the combined weight of substantially spherical glass particles sized in the range of 0.15-0.25 millimeters and having a hardness on the MOH scale of approximately 5.5.

Abstract: A seismic exploration method and system employing a streamer that houses at least one pair of orthogonally mounted hydrophones. The streamer may be operated downhole in a well, or may be towed in a body of water by a marine vessel. In the downhole embodiment, the invention permits detection of seismic signals of interest with suppression of noise due to tube waves and (dipole and monopole) modal waves propagating in and along the well, and without the need for locking the seismic detectors to the wall of the well. In the marine embodiment, the invention permits selective detection of waves incident from any incidence direction of interest (including the horizontal and vertical directions). In all embodiments, the incidence angle of the detected seismic wave is determined. The amplitude of the detected wave may also be determined from the incidence angle and the amplitude components detected at each hydrophone.

Abstract: An earth drilling bit incorporating a tensioned linkage type bit wear indicator. A tensioned linkage extends through the bit between a wear sensor and a device for altering the resistance of the bit to receiving drilling fluid from the drill string. On detecting a predetermined degree of wear, the wear sensor releases the tension in the tensioned linkage. This activates the flow resistance altering device, causing the flow rate and/or pumping pressure of the drilling fluid to change. The tensioned linkage passes through two intersecting passageways in the bit. A guide element is inserted at the intersection of the two intersecting passageways. The guide element routes the tensioned linkage between the two passageways.

Abstract: An earth drilling bit incorporating a bit wear indicator. The bit wear indicator includes: a sensor to detect wear at a selected point on the bit; a device for altering the resistance of the bit to receiving drilling fluid from the drill string; and, a tensioned linkage extending between the wear sensor and the flow resistance altering means. On detecting a predetermined degree of wear, the wear sensor releases the tension in the tensioned linkage. This activates the flow resistance altering device, causing the flow rate and/or pumping pressure of the drilling fluid to change. This serves as a signal that the predetermined wear condition has been achieved. The bit wear indicator can be adapted to monitor many different types of bit wear, including bearing wear in roller-cone type bits and gauge wear in all types of bits.

Abstract: A method and apparatus for orienting a flowline so that it may be remotely connected to a riser connected to an offshore structure. The apparatus includes a structural guide, connected to the offshore structure, that is capable of being rotated so that the front side of the structural guide is directed toward the lead end of the flowline. The structural guide is designed in such a manner so that is is automatically rotated by the cable which is used to pull the flowline to the offshore structure when tension is applied to the cable. The lead end of the flowline is directed upwardly by a pipe guide. The pipe guide has riser guidepost recepticals that receive guideposts as they are lowered from the offshore structure by guidelines. The guidelines and guideposts direct the riser into position over the lead end of the flowline for final connection.

Abstract: An arctic offshore platform adapted for use in hydrocarbon exploration and production operations conducted in relatively shallow waters with low to moderate ice environments. The arctic offshore platform of the present invention includes one or more support legs. Each support leg includes a base resting on the ocean floor, a central support column extending upward through the base to a position above the ocean surface and a sloped-sided member seated atop the base and extending upward around the central support column to a position above the ocean surface. In installation, the base and central support column are installed and secured to the ocean floor as a unit. Following this, the sloped-sided member is secured atop the base. The sloped-sided member causes ice sheets which may impact the support leg to fail in flexure, thus reducing the overall ice loadings on the support leg relative to the loading which would exist were the sloped-sided member absent.

Abstract: A method for logging a cased well to determine the quantity and location of any barite weighted drilling fluid in the annulus between the casing and the wall of the wellbore. A tool assembly having a neutron generator and a gamma scintillation detector is used to log the zone of interest. The neutrons introduced into the well by the neutron generator convert a portion of the barium-138 in the drilling fluid to barium-137m. The magnitude of the gamma photon peak charactristic of the decayof barium-137 is used to identify the quantity of drilling fluid present in the annulus as a function of depth. This method is especially useful identifying the existence of channels in a cemented wellbore annulus.

Abstract: A tether and tether tensioning system for a tension leg platform. A plurality of elongate tethers 12 are used to secure a tension leg platform hull 20 to a foundation 14 at the ocean floor. Each tether 12 has a lower end secured to the ocean floor foundation 14. The tethers 12 extend upward to a position slightly below the bottom of the hull 20. A tether securing and tensioning system 30 is positioned within the hull 20 for each tether 12. This system includes a tether extender 22 positioned within a shroud 28 in the hull bottom. The tether extender 22 includes a tether latch 24 at its lower end. The tensioning system is adapted to lower the tether extender 22 downward below the hull 20 to permit the tether extender 22 to latch to the tether 12. The securing and tensioning system 30 then raises the tether extender 22 to tension the tether 12. The tether tensioning system of the present invention permits use of a simplified method for installing TLPs.

Abstract: The invention provides an apparatus for limiting tension produced in a tubular string extending from a packer set in a subterranean well to the well surface. Such apparatus comprises a receptacle secured to the packer and defining an elongated seal bore, and a mandrel telescopically and sealably related to the seal bore, the mandrel being connected to the bottom end of the tubing string. In one embodiment, a collet, incorporated in the receptacle for cooperating with an abutment formed on the mandrel, thereby securing the mandrel and the receptacle in a telescopically contracted position until sufficient tensile force is exerted on the mandrel to cause the collet arms to be expanded by the abutment to permit upward movement of the mandrel relative to the receptacle.

Abstract: The shear wave velocity of the formation is determined by logging the fastest component of the guided wave generated by the generating means. This method is advantageous for logging the shear wave velocities of soft formations. If the generating means of a multipole acoustic logging device radiates at frequencies including a critical frequency, the fastest component of the guided wave generated by the generating means will have substantially the same velocity as a shear wave traveling in the earth formation. By logging the velocity of this fastest component, the shear wave velocity of the earth formation is determined.

Abstract: This application discloses a process for drilling and primary cementing a well using a drilling fluid containing a polymeric material which may be cemented into a well cement by irradiation with a suitable radioactive source.

Abstract: This application discloses a process for drilling and primary cementing a well using a drilling fluid containing a polymeric material which may be converted into a well cement by contact with an initiator and, optionally, by irradiation with a suitable radioactive source.

Abstract: A system for mating an integrated deck structure with an offshore substructure is provided. The system comprises a spud can attached to a leg of the integrated deck structure and a bin attached to a leg of the substructure for receiving the spud can. The bin contains a bed comprising a medium having variable stiffness and damping characteristics which is utilized to minimize the dynamic forces that occur between the integrated deck structure and the substructure during the mating procedure.

Abstract: A pipeline system designed for withstanding elevated levels of pressure from external sources. Pressurized gas is introduced into an annulus between an outer pipe jacket and insulation material, which in turn surrounds a pipe, to supply structural support.