Abstract: A quantitative evaluation method for integrity and damage evolution of a cement sheath in an oil-gas well is provided based on a fractal theory, an image processing technology, structural features and failure mechanisms of a casing-cement sheath-formation combination. The method uses correlations among fractal dimensions of casing-cement sheath interface morphology, cement sheath microscopic pore morphology, particle morphology of an initial blank group, and macroscopic mechanical properties including a radial cementing strength of the cement sheath interface, a tensile strength, and a compressive strength to quantitatively evaluate the integrity of the cement sheath of the blank group.

Abstract: A downhole displacement impact method and an impact drilling tool are provided, which relates to the field of drilling tools. The downhole displacement impact drilling tool includes a flow passing sleeve, a first main shaft, an impact-bearing seat, and a second main shaft that are all formed by annular structures and are connected in sequence from top to bottom. A vibration sleeve, a vibration starting seat, and an impact head are connected in sequence from top to bottom on the impact-bearing seat. The vibration sleeve is connected and fixed to the impact head through a connecting sleeve. The vibration starting seat synchronously rotates with the impact-bearing seat through a spline connection therebetween. The vibration starting seat generates an up-down periodic displacement along an axial direction of the vibration starting seat during rotating.

Abstract: The present disclosure provides a two-stroke pumping method and oil production device, and relates to the technical field of oil production. The oil production device comprises a pump body, wherein the oil production device further comprises a central tube of a hollow structure, and the central tube is partially located in the pump body and coaxially arranged with the pump body; a traveling valve and a standing valve are arranged on the left side and the right side of the outer wall of the central tube respectively, and the traveling valve is arranged between the pump body and the central tube; the standing valve is located outside the pump body; the traveling valve and the standing valve are matched with the pump body and the central tube to form an oil pumping space; and an oil pumping assembly is further arranged in the oil pumping space.

Abstract: A downhole displacement impact method and an impact drilling tool are provided, which relates to the field of drilling tools. The downhole displacement impact drilling tool includes a flow passing sleeve, a first main shaft, an impact-bearing seat, and a second main shaft that are all formed by annular structures and are connected in sequence from top to bottom. A vibration sleeve, a vibration starting seat, and an impact head are connected in sequence from top to bottom on the impact-bearing seat. The vibration sleeve is connected and fixed to the impact head through a connecting sleeve. The vibration starting seat synchronously rotates with the impact-bearing seat through a spline connection therebetween. The vibration starting seat generates an up-down periodic displacement along an axial direction of the vibration starting seat during rotating.