Grading hoop for well cementation and using method thereof

Abstract

The invention discloses a grading hoop for well cementation and a using method thereof, and belongs to the technical field of oil well sealing equipment, the grading hoop comprises an upper well cementation device, a lower well cementation device is arranged below the upper well cementation device, the upper well cementation device and the lower well cementation device are both connected with a connecting device, and the upper well cementation device and the lower well cementation device are both arranged in an outer sleeve. According to the grading hoop for well cementation and the using method of the grading hoop, the structure is simple, operation is easy, a primary well cementation technology is modified into secondary bump pressure, cement leakage can be effectively prevented, the cement can be prevented from being pumped out by arranging the sealing ring, and the sealing performance between the grading hoop and the cement can be kept.

Description

Technical Field

[0001] The invention relates to the technical field of oil well sealing equipment, in particular to a grading collar for cementing and a use method thereof. Background Art

[0002] Well completion is an important project that connects drilling and oil production. At present, most of the complex wells such as horizontal wells and high-angle wells in oil fields use the traditional casing cementing and perforating completion process. The main problems of this process are that the drilling fluid is not completely replaced, there is retention in the horizontal section, the cement ring is not strong enough, the cement slurry is longitudinally channeled, and there is "continuous casing pressure" (SCP), which reduces the cement isolation effect and affects the production of oil and gas wells. China has begun to promote the large-scale application of horizontal well drilling and completion technology to achieve the goal of continuous production in oil and gas fields. Therefore, improving the wellbore integrity of horizontal wells and improving the cementing quality are of great significance to increasing and stabilizing the production of single wells in the future.

[0003] In the prior art, the oil layer casing cementing all adopts a one-time cementing process. Since leakage often occurs during cementing, the one-time cementing process can no longer meet the cementing requirements. Summary of the invention

[0004] The purpose of the present invention is to provide a grading collar for cementing and a method for using the same, which has a simple structure and is easy to operate. By modifying the primary cementing technology into a secondary impact pressure, cement leakage can be effectively prevented. By setting a sealing ring, cement can be prevented from being pumped out, thereby maintaining the sealing between the two.

[0005] To achieve the above-mentioned purpose, the present invention provides a grading collar for cementing and a method of using the same, comprising an upper cementing device, a lower cementing device being arranged below the upper cementing device, the upper cementing device and the lower cementing device being both connected to a connecting device, and the upper cementing device and the lower cementing device being both placed in an outer sleeve.

[0006] Preferably, the upper cementing device comprises a first ball seat, the first ball seat is fixedly connected to the first sliding sleeve, and a first limiting pin is fixedly connected to the outside of the first sliding sleeve.

[0007] Preferably, the lower cementing device comprises a second ball seat, the second ball seat is fixedly connected to the second sliding sleeve, a second limiting pin is fixedly connected to the outside of the second sliding sleeve, and the inner diameter of the second ball seat is smaller than the inner diameter of the first ball seat.

[0008] Preferably, the number of the first limiting pins and the second limiting pins are both two, and they are symmetrically arranged on the outer walls of the first sliding sleeve and the second sliding sleeve respectively.

[0009] Preferably, four mounting holes and two cement circulation holes are provided on the surface of the outer sleeve, and the two first limiting pins and the two second limiting pins are respectively placed in the four mounting holes.

[0010] Preferably, a sealing ring is provided between the first sliding sleeve and the outer sleeve, and between the second sliding sleeve and the outer sleeve. A sealing ring is provided at the bottom of the first sliding sleeve, and the bottom of the first sliding sleeve matches with the top of the second sliding sleeve.

[0011] Preferably, the connecting device includes an upper joint and a lower joint, the lower end of the upper joint is placed in the outer sleeve, and a sealing ring is provided between the upper joint and the outer sleeve, and the inner diameter of the upper end of the upper joint is larger than the inner diameter of the upper joint in the outer sleeve.

[0012] Preferably, the upper end of the lower joint is placed in the outer sleeve, and a sealing ring is provided between the upper end of the lower joint and the outer sleeve, and the inner diameter of the upper end of the lower joint is larger than the inner diameter of the lower end.

[0013] Preferably, an end face is provided at the upper end of the lower joint, and the length of the second sliding sleeve is smaller than the distance from the end face of the lower joint to the cement circulation hole.

[0014] The present invention also provides a method for using the above-mentioned grading collar for cementing, comprising the following steps:

[0015] S1. When cement needs to be poured into the interior, the first-level rubber plug is put in. The first-level rubber plug falls along the pipeline into the grading hoop, first passes through the first ball seat, then gets stuck on the second ball seat, and cuts off the second limit pin under the action of gravity. The second ball seat drives the second sliding sleeve to move downward until the lower end of the second sliding sleeve is placed on the end surface of the lower joint, and the second sliding sleeve stops sliding downward. At this time, the cement circulation hole is opened;

[0016] S2, pouring cement into the inside, and the cement flows out from the inside of the grading hoop through the cement circulation hole until the cement filling is completed;

[0017] S3. After the cement filling is completed, the secondary rubber plug is put in. The secondary rubber plug goes into the grading hoop along the pipeline and is stuck on the first ball seat. The first limit pin is cut off under the action of gravity. The first ball seat drives the first sliding sleeve to move downward until the lower end of the first sliding sleeve is placed on the end face of the upper end of the second sliding sleeve. The first sliding sleeve stops sliding downward and the cement circulation hole is closed.

[0018] Therefore, the present invention adopts the above-mentioned graded collar for cementing and its use method, which has a simple structure and is easy to operate. By modifying the primary cementing technology into a secondary impact pressure, cement loss can be effectively prevented, and by setting a sealing ring, cement can be prevented from being pumped out, thereby maintaining the sealing between the two.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a structural schematic diagram of a grading collar for cementing and a method for using the same in an embodiment.

[0021] Reference numerals

[0022] 1. Outer sleeve; 2. First ball seat; 3. First limit pin; 4. First sliding sleeve; 5. Second ball seat; 6. Second limit pin; 7. Second sliding sleeve; 8. Upper joint; 9. Lower joint; 10. Sealing ring; 11. Cement circulation hole. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0024] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0025] Embodiment 1

[0026] like Figure 1 As shown, the present invention provides a grading collar for cementing and a method for using the same, comprising an upper cementing device, a lower cementing device is provided below the upper cementing device, the upper cementing device and the lower cementing device are both connected to a connecting device, and the upper cementing device and the lower cementing device are both placed in a jacket 1. The lower cementing device is used to expose a cement circulation hole 11 when moving downward and fill cement inside, the upper cementing device is used to block the cement circulation hole 11, and the connecting device is used to connect the grading collar to the pipeline.

[0027] The upper cementing device includes a first ball seat 2, which is fixedly connected to a first sliding sleeve 4, and a first limit pin 3 is fixedly connected to the outside of the first sliding sleeve 4. When in use, the secondary rubber plug in the first ball seat 2 will drive the first ball seat 2 to move downward, and the first limit pin 3 will be cut off during the movement, and the fixed connection mode of the first sliding sleeve 4 and the outer sleeve 1 will be changed to a sliding connection, and the first sliding sleeve 4 will slide downward inside the outer sleeve 1.

[0028] The lower cementing device includes a second ball seat 5, which is fixedly connected to a second sliding sleeve 7. A second limiting pin 6 is fixedly connected to the outside of the second sliding sleeve 7. The inner diameter of the second ball seat 5 is smaller than the inner diameter of the first ball seat 2. When in use, the primary rubber plug in the second ball seat 5 will drive the second ball seat 5 to move downward. While moving, the second limiting pin 6 will be cut off, and the fixed connection mode of the second sliding sleeve 7 and the outer sleeve 1 will be changed to a sliding connection, and the second sliding sleeve 7 will slide downward inside the outer sleeve 1.

[0029] There are two first limit pins 3 and two second limit pins 6, which are symmetrically arranged on the outer walls of the first sleeve 4 and the second sleeve 7, respectively. The first limit pins 3 and the second limit pins 6 can fix the first sleeve 4 and the second sleeve 7 inside the outer sleeve 1 when not in use. Four mounting holes and two cement circulation holes 11 are arranged on the surface of the outer sleeve 1, and the two first limit pins 3 and the two second limit pins 6 are respectively placed in the four mounting holes.

[0030] A sealing ring 10 is provided between the first sliding sleeve 4 and the outer sleeve 1, and between the second sliding sleeve 7 and the outer sleeve 1. A sealing ring 10 is provided at the bottom of the first sliding sleeve 4, and the sealing ring 10 can prevent the cement slurry from being pumped out and maintain the sealing between the two. The bottom of the first sliding sleeve 4 cooperates with the top of the second sliding sleeve 7, so that when the first sliding sleeve 4 slides downward, it stops sliding when it touches the second sliding sleeve 7.

[0031] The connection device includes an upper joint 8 and a lower joint 9, which are connected to pipelines respectively. The lower end of the upper joint 8 is placed in the outer sleeve 1, and a sealing ring 10 is provided between the upper joint 8 and the outer sleeve 1. The inner diameter of the upper end of the upper joint 8 is larger than the inner diameter of the upper joint 8 in the outer sleeve 1.

[0032] The upper end of the lower joint 9 is placed in the outer sleeve 1, and a sealing ring 10 is provided between the outer sleeve 1. The inner diameter of the upper end of the lower joint 9 is larger than the inner diameter of the lower end. An end face is provided at the upper end of the lower joint 9. The length of the second sliding sleeve 7 is smaller than the distance from the end face of the lower joint 9 to the cement circulation hole 11.

[0033] The present invention also provides a method for using the above-mentioned grading collar for cementing, comprising the following steps:

[0034] S1. When cement needs to be poured into the interior, a first-level rubber plug is put in. The first-level rubber plug falls into the grading hoop along the pipeline, first passes through the first ball seat 2, and then is stuck on the second ball seat 5. Under the action of gravity, the second limit pin 6 is cut off. The second ball seat 5 drives the second sliding sleeve 7 to move downward until the lower end of the second sliding sleeve 7 is placed on the end surface of the lower joint 9. The second sliding sleeve 7 stops sliding downward, and the cement circulation hole 11 is opened.

[0035] S2, pour cement into the interior, and the cement flows out from the inside of the grading hoop through the cement circulation hole 11 until the cement filling is completed.

[0036] S3. After the cement filling is completed, the secondary rubber plug is put in. The secondary rubber plug enters the grading hoop along the pipeline and is stuck on the first ball seat 2. The first limit pin 3 is cut off under the action of gravity. The first ball seat 2 drives the first sliding sleeve 4 to move downward until the lower end of the first sliding sleeve 4 is placed on the end face of the upper end of the second sliding sleeve 7. The first sliding sleeve 4 stops sliding downward, and the cement circulation hole 11 is closed.

[0037] Therefore, the present invention adopts the above-mentioned graded collar for cementing and its use method, which has a simple structure and is easy to operate. By modifying the primary cementing technology into a secondary impact pressure, cement loss can be effectively prevented, and by setting a sealing ring, cement can be prevented from being pumped out, thereby maintaining the sealing between the two.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A grading collar for cementing, characterized in that: The utility model comprises an upper cementing device, a lower cementing device is arranged below the upper cementing device, the upper cementing device and the lower cementing device are both connected with a connecting device, and the upper cementing device and the lower cementing device are both placed in an outer sleeve.

2. A grading collar for cementing according to claim 1, characterized in that: The upper cementing device comprises a first ball seat, the first ball seat is fixedly connected to the first sliding sleeve, and a first limiting pin is fixedly connected outside the first sliding sleeve.

3. A grading collar for cementing according to claim 2, characterized in that: The lower cementing device comprises a second ball seat, which is fixedly connected to the second sliding sleeve. A second limiting pin is fixedly connected outside the second sliding sleeve. The inner diameter of the second ball seat is smaller than that of the first ball seat.

4. A grading collar for cementing according to claim 3, characterized in that: The number of the first limiting pins and the number of the second limiting pins are both two, and they are symmetrically arranged on the outer walls of the first sliding sleeve and the second sliding sleeve respectively.

5. A grading collar for cementing according to claim 4, characterized in that: The outer sleeve surface is provided with four mounting holes and two cement circulation holes, and two first limiting pins and two second limiting pins are respectively placed in the four mounting holes.

6. A grading collar for cementing according to claim 5, characterized in that: A sealing ring is arranged between the first sliding sleeve and the outer sleeve, and between the second sliding sleeve and the outer sleeve. A sealing ring is arranged at the bottom of the first sliding sleeve, and the bottom of the first sliding sleeve matches with the top of the second sliding sleeve.

7. A grading collar for cementing according to claim 6, characterized in that: The connecting device comprises an upper joint and a lower joint. The lower end of the upper joint is placed in the outer sleeve and a sealing ring is arranged between the upper joint and the outer sleeve. The inner diameter of the upper end of the upper joint is larger than the inner diameter of the upper joint in the outer sleeve.

8. The stepping collar for cementing according to claim 7, characterized in that: The upper end of the lower joint is placed in the outer sleeve, and a sealing ring is arranged between the lower joint and the outer sleeve. The inner diameter of the upper end of the lower joint is greater than the inner diameter of the lower end.

9. A grading collar for cementing according to claim 8, characterized in that: An end face is arranged at the upper end of the lower joint, and the length of the second sliding sleeve is smaller than the distance from the end face of the lower joint to the cement circulation hole.

10. A method for using the cementing grading collar according to claim 9, characterized in that: The following steps are involved: S1. When cement needs to be poured into the interior, the first-level rubber plug is put in. The first-level rubber plug falls along the pipeline into the grading hoop, first passes through the first ball seat, then gets stuck on the second ball seat, and cuts off the second limit pin under the action of gravity. The second ball seat drives the second sliding sleeve to move downward until the lower end of the second sliding sleeve is placed on the end surface of the lower joint, and the second sliding sleeve stops sliding downward. At this time, the cement circulation hole is opened; S2, pouring cement into the inside, and the cement flows out from the inside of the grading hoop through the cement circulation hole until the cement filling is completed; S3. After the cement filling is completed, the secondary rubber plug is put in. The secondary rubber plug goes into the grading hoop along the pipeline and is stuck on the first ball seat. The first limit pin is cut off under the action of gravity. The first ball seat drives the first sliding sleeve to move downward until the lower end of the first sliding sleeve is placed on the end face of the upper end of the second sliding sleeve. The first sliding sleeve stops sliding downward and the cement circulation hole is closed.

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