A drill-free step-by-step cementing device and its application method

Abstract

The invention relates to the technical field of petroleum and natural gas exploration and development, in particular to a plug-free step-by-step cementing device and a use method thereof. The plug-free step-by-step cementing device includes an outer cylinder and an inner cylinder, the side wall of the outer cylinder is provided with a first through hole, the side wall of the inner cylinder is provided with a second through hole, and the lower end of the outer cylinder is provided with a lower joint , the upper end is provided with an upper joint, and a closing sliding sleeve and an opening sliding sleeve that can block or connect the first through hole and the second through hole are arranged between the outer cylinder and the inner cylinder from top to bottom, so The lower end surface of the inner cylinder is axially provided with a guide chute, and the guide rod mechanism corresponding to the guide chute is fixed on the inner side wall of the lower joint through the fourth shear nail, and the inner cylinder and the guide rod mechanism can pass through The overshot fishes out the wellbore. The invention achieves the internal penetration of the graded cementing device by fishing out the accessories, without the need for drilling plugs, has a large internal diameter, high completion efficiency, stable connection of pipe strings, good shock absorption effect, process stability and safety.

Description

technical field [0001] The invention relates to the technical field of petroleum and natural gas exploration and development, in particular to a plug-free step-by-step cementing device and a use method thereof. Background technique [0002] During oil and gas well cementing construction, cementing cement needs to be injected into the wellbore, and then a cement plug is lowered into the well to squeeze the cementing cement in the wellbore into the space between the open hole wall and the tubing. In some special occasions, the staged cementing process is required to meet the needs of on-site cementing construction, such as wells with too much cement injected at one time, wells whose formation cannot withstand excessive liquid column pressure, and wells that need to be isolated when drilling complex formations. The large temperature difference between the top and bottom of the well and the cementing section makes the performance of the cement slurry difficult to meet, including...

AI Technical Summary

Problems solved by technology

[0003] 1. The drilling time is long, and the opening and closing sliding sleeves of the hydraulically opened and hydraulically closed graded cement injectors are all made of cast aluminum, with a small inner diameter and a large tool length. At the same time, the rubber plug seat or blind plate are all made of cast aluminum Processing, which brings about the problems of heavy drilling and milling workload and long drilling and milling time, which leads to the extension of the completion cycle. In addition, there are also problems such as drilling deviation, drilling leakage and graded cementing equipment, which greatly affect the later oil recovery operation;

[0004] 2. After drilling and milling, the internal diameter is small. For 7in casing, a φ152mm drill bit is usually used for drilling and milling construction. After the drilling plug is completed, the diameter is small, which is not conducive to the running of the subsequent construction pipe string;

[0005] 3. During the pressure holding process, the opening sliding sleeve and the closing sliding sleeve slide under pressure and collide with the pipe body, causing a large vibration and affecting its service life and sealing performance;

[0006] 4. The locking performance between the graded cement injector and the pipe string is poor, which affects the connection stability of the pipe string

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