Abstract: A water injection system that includes a primary water injection line; an injection fluid supply tank; a high pressure injection pump in fluid communication with the injection fluid supply and primary water injection line for pumping injection fluid in injection fluid supply tank through the primary water injection line; a polymer gel supply tank; and a high pressure chemical injection pump in fluid communication with the polymer gel supply tank and the water injection line configured to pump polymer gel having a viscosity of at least about 50,000 cP (at 20° C. measured using a Bohlin Rheometer CSR 50, cone and plate measuring system CP 4°/40 mm, single shear rate 1/s) in the polymer gel supply tank into the water injection line for mixture with injection fluid is disclosed.

Abstract: A method of microbial enhanced oil recovery from an oil-bearing formation that involves treating the water that is to be injected into the oil-bearing formation to enable microbial activity and adding oxygen to aid microbial activity. The treatment applied to the water is based, at least in part, upon establishing at least one condition in the oil-bearing formation favorable to microbial activity that enhances movement of oil from the oil-bearing formation.

Abstract: A method of optimizing recovery of oil from a formation that includes injecting an oil tracer into an injection well in the formation and applying a tertiary oil recovery process for recovering the oil from the formation. A production well is monitored to detect the oil tracer in oil from the production wells within particular times. The method also includes modifying the tertiary oil recovery process based on the detection of the oil tracer in oil from the production well.

Abstract: A method of recovering oil from a formation that includes the use of surfactants at low concentrations. The surfactant may be an oleophilic surfactant. The method may include conditioning an oil recovery system to inhibit microbes that could consume the oleophilic surfactant. A method that determines the concentration of a surfactant that is sufficient to change the interfacial tension between oil and water in a near well bore area of an injection well in a formation but does not require changing the interfacial tension between oil and water outside the near well bore area.

Abstract: A method of microbial enhanced oil recovery from an oil-bearing formation that involves treating the water that is to be injected into the oil-bearing formation to enable microbial activity and adding oxygen to aid microbial activity. The treatment applied to the water is based, at least in part, upon establishing at least one condition in the oil-bearing formation favorable to microbial activity that enhances movement of oil from the oil-bearing formation.

Abstract: A water injection system that includes a primary water injection line; an injection fluid supply tank; a high pressure injection pump in fluid communication with the injection fluid supply and primary water injection line for pumping injection fluid in injection fluid supply tank through the primary water injection line; a polymer gel supply tank; and a high pressure chemical injection pump in fluid communication with the polymer gel supply tank and the water injection line configured to pump polymer gel having a viscosity of at least about 50,000 cP (at 20° C. measured using a Bohlin Rheometer CSR 50, cone and plate measuring system CP 4°/40 mm, single shear rate 1/s) in the polymer gel supply tank into the water injection line for mixture with injection fluid is disclosed.

Abstract: A method of treating a hydrocarbon-bearing measure such as an oil-bearing rock formation (13). The method comprises: injecting water containing a source of vitamins, phosphates and an electron acceptor such as nitrate into the formation at first location (10) and allowing anaerobic bacteria, which are either already present in the formation (13) or which are introduced simultaneously to multiply using the oil as their main carbon source. This establishes a biomass layer (16) which acts to dissociate the oil from the rock formation (13). The dissociated oil is removed via an outlet (15). The vitamins are supplied by means of a controlled-release medium.

Abstract: This invention relates to a torque release coupling for use in drill strings comprising an outer string part (1) rotatably mounted outside a radially inner string part (2), and a rotation lock (3) positioned between them. The rotation lock (3) is coupled to a first of said string parts (1, 2) with a coupling device (4, 9) adapted to allow axial shifts relative to the first string part, and comprising axial gripping organs (5) adapted for releasable engagement with cooperating gripping organs in the second string part, the rotation lock (3) comprising a spring (6) or similar adapted to apply an axial force on the rotation lock (3) directed against the cooperating gripping organs (5) from the first string part.

Abstract: A method of microbial enhanced oil recovery for recovering oil from an oil-bearing rock formation (13). The method comprises: injecting water containing a source of vitamins, phosphates and an electron acceptor such as nitrate into the formation at first location (10) and allowing anaerobic bacteria, which are either already present in the formation (13) or which are introduced simultaneously to multiply using the oil as their main carbon source. This establishes a biomass layer (16) which acts to dissociate the oil from the rock formation (13). The dissociated oil is removed via an outlet (15).

Abstract: This invention relates to a torque release coupling for use in drill strings comprising an outer string part (1) rotatably mounted outside a radially inner string part (2), and a rotation lock (3) positioned between them. The rotation lock (3) is coupled to a first of said spring parts (1, 2) with a coupling device (4, 9) adapted to allow axial shifts relative to the first string part, and comprising axial gripping organs (5) adapted for releasable engagement with cooperating gripping organs in the second string part, the rotation lock (3) comprising a spring (6) or similar adapted to apply an axial force on the rotation lock (3) directed against the cooperating gripping organs (5) from the first spring part.

Abstract: Device for annular isolation in oil/gas wells comprising a production tube, the production tube comprises coaxially positioned, cylindrical sleeve (5) having in one end an at least partially radially directed opening slot (2), said sleeve including a cylindric sealing crown (1) coupled in one end to a release mechanism (3, 4) adapted to push the sealing crown (1) out through the opening, said sealing crown (1) in its other end being expandable in the tangential direction.

Abstract: A down hole motor assembly includes a hydraulic drive portion, a drill bit operatively connected to the drive portion and a disengage mechanism (11) arranged to disengage drive to the drill bit. The disengage mechanism (11) is arranged to be actuated by supplying drilling fluid to the drive portion at a flow rate which is greater than the flow rate at which fluid is supplied to run the drive portion during normal drilling. The disengage mechanism is arranged to be re-set so that drive is reconnected to the drill bit when the fluid supply to the drive portion is shut off.

Abstract: Air is introduced into the injection water for microbial enhanced oil recovery. The injection water is passed through an ejector where it is entrained and the oxygen subsequently dissolves in the water.

Abstract: A method for removing hydrogen sulfide in drilling mud comprises adding to the drilling mud which is circulated in a borehole a relatively sparingly soluble divalent iron salt having a solubility from 0.1 to 1000 ppm at room temperature in the drilling mud, whereby the hydrogen sulfide reacts with the divalent iron salt to form iron sulfide.

Abstract: A plugging liquid for plugging of a zone of a subterranean formation around a drill hole, consisting of an emulsion comprising (a) a continuous phase containing a hydrophobic liquid, an emulsifier and a crosslinking agent for a polysaccharide, and (b) a discontinuous phase containing water and a polysaccharide. A variant of the plugging composition contains in addition a weighting material in the discontinuous phase. Also described is a method for preparing the plugging liquid and a method for plugging a zone of a subterranean formation penetrated by a drill hole in fluid communication with the zone, according to which method the new plugging liquid is injected into the zone via the drill hole and is subjected to high shear forces in the drill hole, whereby the polysaccharide and the crosslinking agent are brought into contact with one another with resulting initiation of a crosslinking of the polysaccharide and the crosslinking agent and a setting of the plugging liquid.

Abstract: An apparatus for testing a shear thickening plugging fluid that is an emulsion of two components which react with each other to provide a thickening of the fluid when subjected to high stress, such apparatus comprising a cylinder (1) having an inlet (2) with an inlet valve (3) for the plugging fluid and an outlet (4) with an outlet valve (5) for the plugging fluid, a moveable piston (6) sealing against the chamber walls, so that the piston by being moved rearward in the cylinder can suck plugging fluid into the cylinder through the inlet (2), and in a retrograde movement can press the plugging fluid out through the outlet (4), a shear valve (7) connected with the outlet (4), which shear valve (7) is adjustable for adjusting a desired shear stress to be subjected upon the plugging fluid, a means (8, 9) for measuring the pressure drop over the shear valve (7), a receiver means (10) for collecting plugging fluid that has been pressed through the shear valve, and one or more means for measuring properties of the

Abstract: A method of microbial enhanced oil recovery for recovering oil from an oil-bearing rock formation. A population of aerobic bacteria is introduced into the formation at a position spaced from a production borehole. The micro-organisms are adapted to use oil as a carbon source. Pressurised injection water is introduced into the formation via an injection borehole, the water including a source of oxygen and mineral nutrients. The bacteria multiply using the oil as their main carbon source and the oxygen in the injection water as their main oxygen source. In so doing, they dissociate the oil from the rock formation and the dissociated oil is removed via the production borehole by the injection water.