Abstract: An electromagnetic clearance joint and an assembly method thereof are provided, the joint includes a mandrel and a shell. An inner diameter of the shell is larger than an outer diameter of the mandrel, the mandrel includes a first structure part and a second structure part which are connected to each other, and the shell includes a third structure part and a fourth structure part which are connected to each other. A plurality of acting grooves are evenly and circumferentially distributed around the first structure part. An outer diameter of the first structure part is gradually reduced, a plurality of annular ridges are sequentially distributed axially on the outer surface of the second structure part and form the ridge structures, a plurality of grooves axially extending are arrayed circumferentially on the outer surface of the second ridge structure.

Abstract: This invention provides a multi-frac composite perforation device having (i) a gun body having an outer wall, (ii) an inner gunpowder box between adjacent perforating charges in the charge frame 1 of said perforation device, and (iii) a structure for gunpowder charge with an outer gunpowder box 4 attached to an outer wall of the charge frame 1, the gun body has a pressure releasing structure corresponding to a closed end of the perforating charge. This invention further provides a method of using the multi-frac composite perforating device to fracture a formation and the choice of gunpowders and gun body thickness with regards to the pressure required for fracturing a formation.

Abstract: This invention provides a structure for gunpowder charge in multi-frac composite perforation devices that is easy to assemble and transport while the charge volume of gunpowder is increased. In one embodiment of the present invention, an triplet outer gunpowder box is attached onto the outer wall of the charge frame and comprises one middle gunpowder box charged with gunpowder of certain burning rate, and two side-hung gunpowder boxes charged with gunpowder of another burning rate. The two side-hung gunpowder boxes are separately located on the two sides of the middle gunpowder box and are connected with the middle gunpowder box as a unit. The middle gunpowder box is located at a position corresponding to the perforating charge, and has an inner groove for orienting the perforating charge and a through hole through which the jet flow passes.

Abstract: This invention provides a structure for gunpowder charge in multi-frac composite perforation devices that is easy to assemble and transport while the charge volume of gunpowder is increased. In one embodiment of the present invention, an triplet outer gunpowder box is attached onto the outer wall of the charge frame and comprises one middle gunpowder box charged with gunpowder of certain burning rate, and two side-hung gunpowder boxes charged with gunpowder of another burning rate. The two side-hung gunpowder boxes are separately located on the two sides of the middle gunpowder box and are connected with the middle gunpowder box as a unit. The middle gunpowder box is located at a position corresponding to the perforating charge, and has an inner groove for orienting the perforating charge and a through hole through which the jet flow passes.

Abstract: The present invention relates to a composite perforating device with scallops on its inner wall to improve the depth of penetration in the oil reservoir during perforation of oil and gas well. In one embodiment, the scallops on the inner wall of the gun body are located at a position corresponding to the open end of a perforating charge. In one embodiment, the scallop may have a stepped-cylindrical or truncated-conical inner peripheral surface and a conical or flat bottom surface. Alternatively, the scallop may have an inner conical surface. The scallops on the inner wall of the gun body increased the burst heights of the perforating charges such that the penetration depth of the perforating device is increased.

Abstract: A method for testing petroleum or water wells. A tool is secured to a tubing and run into the well and to the reservoir zone to be explored. An upper and a lower seal isolate the reservoir zone. A piston is run into the tubing and pumped down to the tool. When sampling is to take place, a valve is opened and the reservoir fluid, together with drilling fluid filling the well, is allowed to enter the tool while displacing the piston. At the same time, measuring is carried out to identify a tracer added to the drilling fluid. When the tracer no longer can be traced, the drilling fluid contaminated reservoir fluid is displaced out of the tool by the piston and clean reservoir fluid is allowed to enter the tool. The invention also relates to an apparatus for practising the method.

Abstract: The invention relates to a perforating device comprising one or more perforating gun (1) installed in a perforating body (9), a perforating gun head (2) in the uppermost end of the perforating body (9), a perforating gun base (7) in the lowermost end of the perforating body (9) and a detonating device (3) installed inside or outside the perforating head (2), in which a charge frame (10, 22) is installed inside of the perforating body (9). A plurality of perforator unit connected each other by a detonating cord (15) are provided on the charge frame (10, 22). Every perforator unit comprises an explosive box (11) in a charge socket, a charge (13) in charge housing (12) and energy-bearing media (14). Moreover, an energy-bearing media sleeve (28) is provided outside of the perforating device. The perforating device is easy to manufacture with low cost and can be used securely in the operation.

Abstract: Compositions and methods for emulsifying a petroleum product that has been spilled upon a portion of the earth's surface are based upon use of a nonionic, primary surfactant composition comprising a first ethoxylated sorbitol oleate and, preferably, a second ethoxylated sorbitol oleate, and a nonionic, secondary surfactant that is capable of stabilizing and solubilizing the primary surfactant composition such that the resulting emulsifing compositions have a hydrophilic/lipophilic balance between about 12.0 and about 13.5.

Abstract: The invention relates to a device (2) designed and adapted to bring an in per se known mixing body (11) to correspond to a fluid flow area which e.g. is defined by a pipeline (1,3) wherein a two-phase fluid may flow, said fluid being desired to be mixed in connection with sampling (4), and to withdraw the mixing body (11) easily and rapidly in order to release said fluid flow area. For this purpose, the device according to the invention comprises a valve housing (6) formed for fluid-tight connection to said pipeline in an area of two diametrally opposite openings (1', 1") of the pipeline, enclosing said openings. Within the valve housing (6), a sluice body (5) carrying said mixing body (11) has been displaceably arranged. The sluice body (5) and thus the mixing body (11) is displaceable between two main positions. In one main position, the mixing body (11) has been brought to correspond with said fluid flow area.