Abstract: An improved method for placing ball sealers (25) onto casing perforations (17) in a deviated wellbore (10) is disclosed. In this invention, a plurality of ball sealers (25) are introduced into the casing and are transported to the perforations at an interface (26) between two immiscible fluids; the first or leading fluid (21) having a density greater than the ball sealers and the second or trailing fluid (24) having a density greater than the ball sealers.

Abstract: An apparatus is described for securing two offshore mooring sections together. The apparatus is a connector adapted to quickly disengage each mooring section so that an offshore floating storage vessel, having one mooring section attached to it, may be separated from the riser of an single-anchor-leg-mooring system, having the other mooring section attached to it. The connector comprises a pin member engageable with a hook of a latch member. The latch member is rotated once the hook engages the pin member and a plunger then advances into an open region of the hook prohibiting the rotational movement of the latch member and thereby locking the two mooring sections together.

Abstract: An improved offshore platform base (12) is disclosed having three sets of substantially parallel bulkheads (24, 26, 28) which intersect one another at about 120.degree. forming a repeatable array of contiguous triangular (30) and hexagonal-shaped (34) chambers.

Abstract: The present invention relates generally to the composition and method for reducing the permeability of subterranean formations penetrated by a wellbore. The composition of the present invention comprises a wellbore fluid having dispersed therein a fluid loss control agent comprising a polyester polymer which is substantially insoluble in the wellbore fluid. The polymer degrades in the presence of water at an elevated temperature to form small molecules which are soluble in a fluid in the subterranean formation. The method of the present invention comprises reducing the permeability of subterranean formations penetrated by a wellbore by placing the composition of the present invention down the wellbore.

Abstract: A guidance system for centering and guiding various drill strings or risers within a moonpool of a floating structure, e.g. a caisson vessel. The system comprises one or more guidance vehicles. Each vehicle is movably mounted on a separate track. The tracks, in turn, are spaced about the moonpool wall and extend vertically along the wall of the moonpool from the top of the moonpool to a point near its bottom. Each vehicle has a frame and means to mount the frame on its respective track. Two side arms and a center arm are pivotably mounted on the frame and are movable between a closed position and an open position. Mounted at the outer end of each of the arms is an interchangeable workhead assembly which engages a drill string or riser to center and guide the drill string or riser when the arms are in their closed position. Individual lines controlled by winches above the moonpool are attached to each vehicle for independently raising and lowering that vehicle within the moonpool.

Abstract: Apparatus for detecting flaws in the threaded end of a ferromagnetic pipe is disclosed. The apparatus comprises means for applying a magnetic force to produce a field generally axially through the threaded end of the pipe, first and second means adjacent successive crests of a thread for sensing a generally radial magnetic field and generating a first and second signal corresponding to the sensed magnetic fields, and means for differentially connecting the signals generated by said first and second sensing means, whereby a differential output signal is produced in response to a flaw between the crests of the thread being inspected. The apparatus also comprises means for helically rotating said sensing means to follow a path corresponding to the threads of the pipe, whereby the first and second signals vary with time.A method for detecting flaws in the threaded end of a ferromagnetic pipe is also disclosed.

Abstract: A method and apparatus is disclosed for eliminating vertical motion of a downhole tool in a subsea borehole as the tool is being operated by a drill string from a floating vessel. A vertical motion elimination means is incorporated into the drill string at a point which will be adjacent a blowout preventer stack on the marine bottom when the downhole tool is positioned at a desired point in the borehole. The vertical motion elimination means is comprised of a sleeve which is rotatably mounted on the drill string at a fixed vertical position. The sleeve is adapted to be engaged by the blowout preventer stack to fix the sleeve against vertical movement with respect to the preventer. Since the sleeve, itself, is fixed against vertical movement on the drill string, that portion of the drill string which lies below the preventer (hence, the downhole tool) will also be fixed against vertical motion within the borehole.

Abstract: A method and system for separating and sealing sections of a pipeline are disclosed. A spherical member is advanced by pressure along the interior of a pipeline to seat against a restraining member forming a pressure-tight seal. The advancing pressure may then be increased within the pipeline to monitor for leaks in the upstream section of the pipeline.

Abstract: A hollow tubular member, such as a drill string member (15, 16), stuck by differential pressure against the side wall of a wellbore (10), is released by measuring (21) the temperature distribution around the circumference of the member, determining from this measurement the side which is stuck (17), and then perforating (22) the member at the stuck side to flow fluid into the formation and equalize the pressure behind the stuck portion of the member.

Abstract: A clamping mechanism for connecting members in end-to-end relation having a rotatable, actuating ring to radially move loading devices into engagement with one of the members. The translation of rotational movement to radial movement is accomplished by cam mechanisms. The loading devices may be toggle links of a toggle assembly which are supported by one of the members to be connected. Rotation of the actuating ring advances the locking device into engagement which in turn connects and preloads the members.

Abstract: An apparatus is disclosed for minimizing the horizontal forces on an offshore arctic structure due to ice movement. The structure includes a base portion, sloped side walls and a smooth, unobstructed top portion. The structure is substantially submerged in a body of water with the top portion at or near the water surface permitting floating ice sheets which strike the side walls to flex slightly upward and advance along and over the structure without substantially destroying the overall integrity of the ice sheet. In this manner, the horizontal forces on the structure resulting from the ice sheet are minimized due to the elimination of a crushing failure mode of the ice sheet commonly associated with conventional offshore arctic structures.

Abstract: A subsea connection unit for securing an offshore structure to a marine bottom is disclosed. The unit comprises a base adapted to be positioned on the marine bottom and an insert member adapted to be connected to the lower end of the offshore structure. The base has a recess thereon adapted to receive the insert member. Releasable vertical latch means comprised of a plurality of tapered shear blocks are carried by the insert member and cooperate with tapered lugs in the recess to lock the insert member against vertical movement within the recess. Releasable horizontal latch means comprised of a plurality of wedge members are positioned on the base around the recess and cooperate with load surfaces on the insert member to center and lock the insert member against horizontal movement within the recess.

Abstract: A retrievable connector assembly is disclosed for securing two parts together. The assembly includes a guide frame to support the first of two parts and a pair of rotatable shafts with threaded ends to carry male coupling members with pins which extend from each coupling member. The assembly also includes a mounting hub attached to the second part. The mounting hub includes female coupling members having slots to receive the pins of the male coupling members. Rotation of the shafts moves the pins into lateral legs of the slots locking the two parts together. Further rotation of the shafts causes the male coupling members to move upward along the shafts forcing the first and second parts together. The two parts can be separated for retrieval by rotating the shafts in the reverse direction thereby separating the male and female coupling members.

Abstract: An improved offshore arctic structure is disclosed which controls the horizontal forces exerted by impinging ice masses. The structure includes lesser sloped wall sections near the sea floor and steeper sloped wall sections near the water surface. Thus, the deep pressure ridges contact the lesser sloped wall sections and the shallower ice sheets contact the steeper sloped wall section. The slope of all wall sections is chosen so as to keep all horizontal loads due to impinging ice masses below a preselected design maximum.

Abstract: A pressure insensitive, fail-safe subsea valve is disclosed. The valve is manipulator operable for deep water application and does not require conventional diving techniques to install, maintain or remove. The valve is pressure balanced by employing a hollow valve stem which equalizes the pressure on both ends of the stem.

Abstract: A method and appartus are disclosed for making a subsea flowline connection between two pipelines. A connector assembly having a base plate is positioned on the sea floor to receive the ends of two intersecting pipelines. Once one of the pipelines is attached to the base plate, the base plate is displaced horizontally along the sea floor toward the other pipeline. When the second pipeline is attached to the base plate, the ends of the pipelines are a predetermined distance apart and a prefabricated spool piece is then remotely installed. In this manner, the base plate permits the connection of spatial and axial misalignments which otherwise would require the on-site fabrication and installation of a spool piece.

Abstract: A method for measuring the thickness of an ice sheet is disclosed. The resistance of an electric circuit embedded in an ice sheet floating at the surface of a body of water is measured. A relationship between the measured electric resistance and the ice sheet thickness is possible because sea ice has a much larger resistance than sea water and, therefore, acts as an insulator. Thus, the resistance of the circuit is altered by the vertical location of the water's surface on the circuit.

Abstract: A method and apparatus is disclosed for determining the flow rate of drilling fluid flowing from a subaqueous well. The invention may also be used to determine the presence of an abnormal drilling condition during heaving motion of an offshore vessel from which the drilling operation is conducted. The invention measures the volume of fluid passing predetermined locations in the drilling system at particular points in time so as to eliminate the influence that the expansion and contraction of a telescoping section has on the total volume of drilling fluid within the system.

Abstract: A method and apparatus for securing and releasing an underwater flexible line (30) within a channel (20) is disclosed. The channel (20) is formed on the support member (22) of an offshore structure such as the leg of a fixed offshore platform of the tension member of an offshore riser buoy system. The apparatus comprises a sled (22) which advances relative to the channel (20) on a track system. The sled (32) includes an aligning system for orienting and seating the line within the channel (20) as it advances along the length of the structure. Initially, the line is attached to the upper end of the offshore structure, preferably at or above the water surface and allowed to hang freely to the sea bed. Thus, the line is adjacent the channel and readily available for proper aligning and seating within the base of the channel. After the sled aligns and seats the line within the channel, it closes the channel securing the line by means of latches (34) pivotally mounted to one side of the channel.