Abstract: A process is disclosed for enhancing oil recovery in oil-containing reservoirs formed of water-wet sand. The process involves placing oil-wet sand in the near-bore region of a production well. The process can be used to provide an improvement to both a conventional pressure driven fluid drive process and a conventional steam-assisted gravity drainage process. In the fluid drive process, the drive fluid is injected intermittently.

Abstract: The present invention is directed to aspartic protease inhibitors, in particular to HIV protease, renin, pepsin and cathepsin D inhibitors. Inhibitors of the present invention have a 3 to 12-membered heterocyclic core containing at least two heteroatoms which interact with the carboxyl groups of the aspartic acid residues in the active site of the protease to inhibit the action thereof.

Abstract: A method is provided for blocking high permeability channels in subterranean geological formations, using swelling clay. A slurry is prepared by mixing swelling clay, such as bentonite, into an aqueous solution containing the salt of certain cations, which inhibit clay swelling. The cations K.sup.+, Ca.sup.2+ and Mg.sup.2+, among others, are inhibitive of clay swelling. The clay slurry is introduced into a geological formation, where it preferentially enters channels of high permeability. There the slurry is contacted by NaCl brine solution present in natural or injected drive fluids, and the inhibitive cations bound to the clay particles are replaced by Na.sup.+ ions, which attract water molecules and promote clay swelling. The Na.sup.+ -clay swells to up to 10 times its original volume, causing the slurry to acquire a gel-like consistency. The clay gel so formed is capable of blocking the flow of water, and can resist pressure of up to 500 kPa per meter.

Abstract: Polymer composite products, including products made of polymer concrete, reinforced polymer concrete and reinforced plastics, such as bulk molding compound, sheet molding compound, mineral molding compound and advanced molding compound systems, are produced by the simultaneous application of vibration, heat and pressure to a mixture of filler and polymeric binder. The simultaneous application of vibration, heat and pressure provides a protective layer of polymerized binder that protects the surfaces of the mold and provides products that are substantially free of curling, cracking or voids. The process of the present invention substantially reduces the time required to cure polymer composite products.

Abstract: Novel maleimide copolymers have at least two monomeric units, a maleimide unit and a vinyl unit having a pendant group, the pendant group having two to twenty-one carbon atoms, at least one nitrogen atom and at least one oxygen atom. The copolymer has an average molecular weight between about 1,000 and about 6,000,000. Preferred maleimide copolymers include acrylamide/maleimide copolymers, N-vinyl amide/maleimide copolymers, vinyl lactam/maleimide copolymers, alkenyl cyclic imino ether/maleimide copolymers, and acryloylamide/maleimide copolymers. The substantially water soluble maleimide copolymers are useful for inhibiting the formation of clathrate hydrates in a fluid having hydrate-forming constituents by reducing the rate of nucleation, growth, and/or agglomeration of gas hydrate crystals in a petroleum fluid stream, thereby inhibiting the formation of a hydrate blockage in the pipe conveying the petroleum fluid stream.

Abstract: The invention disclosed herein is a method for producing oil from a reservoir after predetermining its residual oil saturation, S.sub.orm. Such a method would displace a hydrocarbon fluid in a subterranean formation using a substantially non-aqueous displacement fluid after a waterflood. The non-aqueous displacement fluid can be introduced as a single bank, in alternating sequence with water, or by other means. The method predetermines S.sub.orm using the difference in the solubility parameters between the hydrocarbon liquid in the formation and the displacement fluid to be used for displacing the hydrocarbon fluid. The solubility parameter of the hydrocarbon liquid can be determined by a variety methods including, but not limited to, (1) using the hydrocarbon liquid's energy of vaporization, .DELTA.E.sub.

Abstract: A method for inhibiting the formation of clathrate hydrates in a fluid having hydrate forming constituents is disclosed. More specifically, the method can be used in treating a petroleum fluid stream such as natural gas conveyed in a pipe to inhibit the formation of a hydrate restriction in the pipe. The hydrate inhibitors used for practicing the method are substantially water soluble polymers formed from a cyclic imino ether. Such polymers may be ring closed cyclic imino ether ("CIE") polymers, ring opened CIE polymers, or combinations thereof. Some examples of ring opened CIE polymers include various N-acyl polyalkyleneimines produced by cationic polymerization, such as N-acyl substituted polyethyleneimine, N-acyl substituted polypropyleneimine, N-acyl substituted polybutyleneimine, N-acyl substituted polypentyleneimine and copolymers thereof.

Abstract: The current invention is an improved method for preventing annular fluid flow following primary cementing of a casing string in a wellbore. The method involves injecting high pressure pulses of a working fluid into a liquid-filled casing string to produce tube waves that will propagate through the casing liquid until they encounter a casing restriction or barrier. This encounter vibrates the casing string. Vibration of the casing string helps to maintain the pressure of the cement slurry at or above the pressure of fluids in the surrounding formations, thereby preventing or reducing annular fluid flow.

Abstract: A threaded connection with improved fatigue-life useful for connecting adjacent sections of a pipe string subject to bending, tensile, and compressive stresses such as a drill collar string is disclosed. The connection comprises a pin member which is threadedly engageable with a corresponding box member. In the preferred embodiment, the inventive connection is designed to have bending strength ratio ("BSR") of about 3.20 or greater, and more preferably, in a range between about 3.20 and about 4.00. The preferred thread form of the connection is a V-type thread form having two flank angles of 30 degrees and a 0.038 inch root radius. Other design features may be used in combination with the threaded connection to further improve the connection's fatigue-life.

Abstract: A method for inhibiting the formation of clathrate hydrates in a fluid having hydrate forming constituents is disclosed. More specifically, the method can be used in treating a petroleum fluid stream such as natural gas conveyed in a pipe to inhibit the formation of a hydrate restriction in the pipe. The method uses a mixture comprising a first additive and a second additive. The mixture produces a synergistic hydrate inhibition effect. The first additive is selected from the class of substantially water soluble polymers. The second additive is selected from the class of ionic or non-ionic organic compounds which have a polar part and nonpolar part with the nonpolar part having an alkyl, alkenyl, or alkynyl group with 12 or fewer carbon atoms.