Abstract: A dynamic crack leaking stoppage evaluation experiment device includes a crack simulation experiment instrument having a dynamic crack simulation mechanism. The dynamic crack leaking stoppage evaluation experiment device can simulate a dynamic change process of a crack from a closed state to an open state. An experiment method can be applied to study a variation range of the width of the crack that have been subjected to self-adaptive leaking stoppage with various combinations of leaking stoppage materials and under different increments, and the method can also be applied to quantitatively study on effecting patterns of rheological parameters and hydraulic parameters of well drilling fluid on stability of a leaking stoppage layer in the dynamic crack, so that enabled is not only simulation of leaking stoppage process of a dynamic crack, but also real-time monitoring and evaluation on leaking stoppage effect and leaking stoppage location inside the dynamic crack.

Abstract: A multi-stage fracturing sliding sleeve is provided, which comprises a fracturing pipe, a shear slip device, a fracturing sleeve, a ball seat support, a first sliding sleeve and a limiting sleeve, the fracturing sleeve seals fracturing ports, the ball seat support and the fracturing pipe are connected through at least one first shear pin, a first spring is arranged between the first sliding sleeve and the limiting sleeve, a second sliding sleeve is arranged below a multi-segment ball seat and connected with the first sliding sleeve, an outer wall of the first sliding sleeve comprises a downward facing annular shoulder, an inner wall of the limiting ring comprises an upward facing annular shoulder, the first spring is located between the downward facing annular shoulder and the upward facing annular shoulder, and an upper end face of the limiting ring limits the axial travel of the first sliding sleeve.

Abstract: The present invention provides a multi-stage fracturing sliding sleeve, with a fracturing ring, a ball seat bearing, a first sliding ring and a limiting ring arranged from top to bottom along a fracturing pipe. All of the fracturing ring, the ball seat bearing and the first sliding ring are in sliding connection with the fracturing pipe, and the fracturing ring forms plugging by sealing fracturing holes in the fracturing pipe in a natural state; the ball seat bearing and the fracturing pipe are connected through first shear pins; a first spring is arranged between the first sliding ring and the limiting ring; the limiting ring limits the axial position of the first sliding ring; multi-blade ball seats are arranged in the ball seat bearing. With a two-stage shear structure, the structure is simplified, and multi-stage fracturing construction can be realized without reducing the inner diameter.