Abstract: A method for creating branch fractures in an oil well, including: injecting a first pad fluid containing a first absorbent resin to a first position of the main fracture; injecting a second pad fluid containing a second absorbent resin to a second position of the main fracture; after the second absorbent resin absorbs water and expands to form a first plugging layer, injecting a third pad fluid free of absorbent resin to the main fracture to build up a pressure at the first plugging layer; exerting the pressure to sides of the main fracture to form a first branch fracture; breaking the first plugging layer to generate a fragment; bridging the fragment to the first absorbent resin to form a second plugging layer; and injecting a third pad fluid to build up a pressure to form a second branch fracture at the first position.

Abstract: Disclosed is a device and method for measuring the magnitude of a seepage force and its influence on effective stress of a formation. The measuring device includes a lower bearing platform having a pressure testing device fixed on an upper part thereof, and a water storage chamber mounted with a seepage water discharge pipe. A confining pressure loading chamber is mounted on the upper part of the lower bearing platform, and the lower bearing platform is used for placing a sample which has 11 measuring points distributed at equal intervals on an outer wall thereof. An upper and a lower permeable pressure-bearing steel sheet are placed on an upper and a lower end surface of the sample, respectively. The invention can improve the validity and accuracy of measurement and make the calculation result of the test more accurate.

Abstract: A method for creating a branch fracture with temporary plugging and pressure buildup using super absorbent resin, comprising: setting a fracturing packer to fracture a target layer by pad fluid to form a main fracture; injecting into the main fracture pad fluid mixed with salt-intolerant super absorbent resin and performing replacement till depth of the main fracture, and then injecting pad fluid mixed with strong salt-tolerant super absorbent resin; after the strong salt-tolerant super absorbent resin absorbs water and expands to form a temporary plugging layer, re-injecting the pad fluid to create a branch fracture with pressure buildup; and lifting injection pressure to break up the temporary plugging layer formed by the strong salt-tolerant super absorbent resin to form residue, transporting the residue to the depth of the main fracture to bridge the temporary plugging layer formed, and re-building up pressure to create a branch fracture.

Abstract: Disclosed is a device and method for measuring the magnitude of a seepage force and its influence on effective stress of a formation. The measuring device includes a lower bearing platform having a pressure testing device fixed on an upper part thereof, and a water storage chamber mounted with a seepage water discharge pipe. A confining pressure loading chamber is mounted on the upper part of the lower bearing platform, and the lower bearing platform is used for placing a sample which has 11 measuring points distributed at equal intervals on an outer wall thereof. An upper and a lower permeable pressure-bearing steel sheet are placed on an upper and a lower end surface of the sample, respectively. The invention can improve the validity and accuracy of measurement and make the calculation result of the test more accurate.

Abstract: The present invention provides a method for further forming a plurality of small fractures in a main fracture. If a radial main fracture is further fractured axially to form a plurality of branch fractures, the stimulated volume of the oil and gas reservoir will be achieved to greatly increase the yield of dense oil and gas. The main contribution of the present invention is to form three-dimensional fracture networks for any low-permeability oil reservoirs to achieve stimulated reservoir volume. The concept is that an original main fracture is further fractured to form a plurality of branch fractures (the branch fractures form included angles with the original main fracture), and the locations for forming the branch fractures in the main fracture and even the size and length of the branch fractures can be controlled artificially, so that the branch fractures can be formed by fracturing where needed.

Abstract: An apparatus for coupling a rupture disc and a perforated casing is disclosed and pertains to the field of petroleum and gas field development tools. The apparatus includes a coupling body. Axially extended swells are provided at intervals in a circumferential direction on the coupling body. Several radial openings are provided on each swell. A nut is provided in each opening. A rupture disc is provided between one end of the nut and a bottom of the opening. A fixing cap is provided at the other end of the nut. A cavity with particular air pressure is formed by the fixing cap, the nut, and the rupture disc. An upper end of the fixing cap is coated with a self-dissolvable softening film. When the apparatus of the present invention is used to perform perforating or fracturing, structural force of a connected casing is not impaired.