A method and an apparatus for sealing perforations or cracks found in an oil well casing. The apparatus includes a hydraulic cylinder with an oil supply section at one end and a rod at another end, a cylindrical liner at least a portion of which is a malleable metal and a receiver, the liner with an outer diameter suitable for entry in to the well casing; and a frusto-conical wedge being disposed at a lower end of the liner and fixedly connected to the rod, the frusto-conical wedge having a section with a diameter larger than an inner diameter of the liner. The method includes lowering the apparatus into the well casing and increasing hydraulic pressure to the hydraulic cylinder sufficient to pull the frusto-conical shaped wedge into the liner providing sufficient lateral force to force sufficient liner material into the perforations or cracks of the well casing to seal the well casing wall

A system includes a processor(s), and a memory coupled to the processor(s) having instructions stored therein. When executed by the processor(s), the instructions cause the processor(s) to perform functions to: apply a treatment for stimulating production to at least a first well in a subterranean formation; determine a flow distribution based on at least one of a first-well measurement or a second-well measurement, the first-well measurement taken at the first well, and the second-well measurement taken at a second well; determine a length of a fracture between the first and second wells, based on the determined flow distribution; determine if the applied treatment at the first well interferes with the second well, based on the determined length of the fracture; and apply a diverting material at the first well if it is determined that the applied treatment interferes with the second well, in order to control well bashing.

A system includes a processor(s), and a memory coupled to the processor(s) having instructions stored therein. When executed by the processor(s), the instructions cause the processor(s) to perform functions to: apply a treatment for stimulating production to at least a first well in a subterranean formation; determine a flow distribution based on at least one of a first-well measurement or a second-well measurement, the first-well measurement taken at the first well, and the second-well measurement taken at a second well; determine a length of a fracture between the first and second wells, based on the determined flow distribution; determine if the applied treatment at the first well interferes with the second well, based on the determined length of the fracture; and apply a diverting material at the first well if it is determined that the applied treatment interferes with the second well, in order to control well bashing.

A method for lifting a tubular string from a wellbore includes cutting the tubular string at a selected depth in the wellbore. A check valve is disposed in the tubular string above the selected depth. An interior of the tubular string is pressurized with gas to displace liquid in the tubing through the check valve. The tubular string is lifted, and a portion of the tubular string extending out of the wellbore is cut.

A method for lifting a tubular string from a wellbore includes cutting the tubular string at a selected depth in the wellbore. A check valve is disposed in the tubular string above the selected depth. An interior of the tubular string is pressurized with gas to displace liquid in the tubing through the check valve. The tubular string is lifted, and a portion of the tubular string extending out of the wellbore is cut.

Cement compositions and methods for using the same in subterranean formations are provided. In one embodiment, the methods include introducing a treatment fluid including an aqueous base fluid, at least one viscoelastic surfactant, a divalent salt, a metal salt; and a metal oxide into a wellbore penetrating at least a portion of a subterranean formation; and allowing the treatment fluid to at least partially set in the subterranean formation.

Cement compositions and methods for using the same in subterranean formations are provided. In one embodiment, the methods include introducing a treatment fluid including an aqueous base fluid, at least one viscoelastic surfactant, a divalent salt, a metal salt; and a metal oxide into a wellbore penetrating at least a portion of a subterranean formation; and allowing the treatment fluid to at least partially set in the subterranean formation.

A method of designing a cement composition may include: minimizing an objective function subject to a plurality of constraints to produce a cement composition including at least one cement component and water; and preparing the cement composition.

This invention relates to the method of assessing the integrity of primary and secondary barriers in the interval where a cement plug is to be installed in the well proposed for abandonment. The technical result of the invention is to enhance the accuracy of wellbore barrier integrity assessment. The method of well integrity assessment below production packer, including inner and outer casings, tubing string and production packer installed inside the casing, and cement sheath and adjacent rocks, comprising the following phases: Identification of the target zone for cement plug installation; installation of a temporary cement plug below the target zone; pressure testing and assessment of tubing and below-packer zone integrity based on steady pressure data or pressure variation in time; creation of a perforation zone in casing and cement below production packer in the target zone; conducting a logging survey including noise, temperature, defectoscopy, and production logging in the target zone during a repeat pressure test; issuance of a findings report on casing and cement integrity and subsequent installation of a cement plug for well abandonment, including rigless operations or remedial cementing at designated locations where integrity failures have been identified on the basis of logging data.

This invention relates to the method of assessing the integrity of primary and secondary barriers in the interval where a cement plug is to be installed in the well proposed for abandonment. The technical result of the invention is to enhance the accuracy of wellbore barrier integrity assessment. The method of well integrity assessment below production packer, including inner and outer casings, tubing string and production packer installed inside the casing, and cement sheath and adjacent rocks, comprising the following phases: Identification of the target zone for cement plug installation; installation of a temporary cement plug below the target zone; pressure testing and assessment of tubing and below-packer zone integrity based on steady pressure data or pressure variation in time; creation of a perforation zone in casing and cement below production packer in the target zone; conducting a logging survey including noise, temperature, defectoscopy, and production logging in the target zone during a repeat pressure test; issuance of a findings report on casing and cement integrity and subsequent installation of a cement plug for well abandonment, including rigless operations or remedial cementing at designated locations where integrity failures have been identified on the basis of logging data.