WO2016039661A1

WO2016039661A1 - Casing string centralizer

Info

Publication number: WO2016039661A1
Application number: PCT/RU2014/000943
Authority: WO
Inventors: Валерий Константинович СМИРНОВ
Original assignee: Общество с ограниченной ответственностью "ОЗБО Иннова Петролеум"; Валерий Константинович СМИРНОВ
Priority date: 2014-09-08
Filing date: 2014-12-15
Publication date: 2016-03-17

Abstract

The claimed invention relates to the oil and gas industry, and more particularly to devices intended for use during the lowering of casing strings, liners or downhole filters into a borehole. The body of a centralizer has a cylindrical longitudinal through opening, the line of symmetry of which coincides with the longitudinal line of symmetry of the centralizer body, and, on the outside, at least three forming ribs, situated along the centralizer body. Additionally, the centralizer body is provided on the outside with at least one mud-breaking rib, which is sharp on the outer side and is situated along the centralizer body. The claimed centralizer provides improved anchoring of a casing string.

Description

Casing Centralizer

The inventive utility model relates to the oil and gas industry, namely, to devices intended for use when lowering casing strings, liners or downhole filters into the well, and that contribute to the destruction of sludge (relatively large pieces of drilled rock), into smaller pieces, which as a result will lead either to the absence of slurry congestion, or at least to better cleaning of the well from sludge at the stage of technological operations for cleaning the well.

Terms used:

A well is a round-cut mine with a diameter many times smaller than the length formed in a rock mass by drilling and securing without access to a person, with a predetermined position in space. d | Cr.7 / sd.asas1et1s.gi / 361 / Well

Casing - designed for fastening boreholes, as well as isolating productive horizons during operation; made up of casing by sequentially making them up (sometimes welding). /http://dic.academic.ru/dic.nsf/enc geolog / 3492 / Casing

Sludge - in the oil and gas industry (well drilling) these are pieces of drilled rock. / Http.7 / neft.academic.ru / 423 / IIInaM

Casing Centralizer (Centralizer) - is an element of the casing string tooling.

/http://dic.academic.ru/dic.nsf/enc geolog / 1954 / Zakolonnaya

Along - (dialect) in the longitudinal direction, in length. / Explanatory Dictionary of Ozhegov / http://dic.academic.ru/dic.nsf/ogegova/2Q134

Across - (adverbial) in breadth, in width, in breadth, sheer in length, in level, (opposite term for the adverb “along”) / Ozhegov's Explanatory Dictionary / http://dic.academic.ru/dic.nsf/enc2p/ 324346 sludge ... (German dirt) - the first part of complex words, written together / B. 3. Bookchina. / Together. Apart. Through a hyphen / http://orthographv.academic.ru/40293 In the process of drilling rock, a well is created; after the drilling is completed, the casing is lowered into the well, technological operations are carried out to clean the well from sludge, after which the string is cemented.

Most of the wells that are drilled in modern times are complex in their spatial structure, i.e.:

1. are directional;

2. have a horizontal section;

3. have one (or more) changes in the azimuth of the well.

It should be noted that the indicated three points often take place simultaneously on one well, which only complicates the spatial profile of the well.

The complex spatial profile of the well leads to the fact that sludge accumulates on its bottom wall; sludge accumulation occurs in directional sections of the well. In directional sections of the well with an angle of 45 ° or more, as well as in horizontal sections of the well, stable slurry formations (congestion) may form that prevent the casing from lowering, as a result of which various problems with the lowering may occur, and sometimes it is even impossible to lower the casing - what is a serious industrial accident.

One of the reasons due to which sludge plugs are formed - pieces of drill cuttings can be so large that it is almost impossible to completely remove them from the well due to technological operations to clean the well from sludge due to their relatively large size.

Although slurry congestion interferes with the casing runoff, however, despite the presence of slurry congestion in the well, the casing can still be successfully lowered to the desired depth, however, work to lower the casing is associated with high risks. As mentioned above, casing string cementing follows and, at this stage, slurry congestion begins to play a negative role for the cementing process. The goal, which is pursued in the process of cementing the casing, is to create such a type of contact in the annulus in the open hole of the well as "casing - cement - rock". This type of contact is required to be created along the entire length of the casing string in the open hole of the well, however, the formation of the specified contact is prevented by sludge that lies on the lower wall of the well, in its directionally and / or horizontal sections. Thus, together you need the type of contact created such a contact as "casing - cement - sludge"; this type of contact after putting the well into operation can lead to various types of production accidents and complications.

A known technical solution, taken as a prototype, containing a cylindrical body made of polyamide with at least 4 ribs located at an angle of 10-20 ° to its longitudinal axis, and the channels between them. (RF patent Ш 2263760, IPC Е21 В17 / 10, priority dated November 26, 2004).

A disadvantage of the known technical solution is the design, which does not contribute to the destruction of pieces of drill cuttings (sludge) into smaller pieces, which would improve the cleaning of the well from drill cuttings (sludge) during circulation, which is performed in the well before cementing the casing.

The authors were tasked with developing a centralizer that ensures the destruction of pieces of cuttings (sludge) into smaller pieces and helps reduce the likelihood of accidents in general.

The problem is solved in that in the casing centralizer, including the centralizer body, containing, inside, a longitudinal through cylindrical hole, the line of symmetry of which coincides with the longitudinal line of symmetry of the centralizer body, and at least three forming ribs located along the centralizer body outside , additionally, from the outside, the centralizer body is provided with at least one sludge-destroying rib, which is made pointed from the outside, located along the centralizer body. In this case, the forming rib is made with the possibility of having a height less than the diameter of the casing or well, into which the centralizer descends, is located either parallel to the longitudinal line of symmetry of the centralizer body, or at an angle to the longitudinal line of symmetry of the body of the centralizer. The sludge-destroying rib is either parallel to the longitudinal line of symmetry of the centralizer body, or at an angle to the longitudinal line of symmetry of the centralizer body, which can be no more than 90 °, mainly 25 °. In addition, the sludge-destroying rib is located between two adjacent forming ribs, mainly in the middle.

The technical effect is to expand the arsenal of funds for this purpose. In addition, in the possibility of destruction of the sludge, in reducing the likelihood of emergencies and obtaining better casing fastening (cementing).

The claimed technical solution is illustrated by drawings. Figure 1 presents a block diagram, where 1 is the body of the centralizer, 2 is a forming rib, 3 is a sludge-destroying rib.

The inventive utility model contains the body of the centralizer 1, which is made having a longitudinal through cylindrical hole. The latter is made to provide the ability to put the centralizer on the casing. In order that the centralizer does not have slopes in operation when resistance arises from the side of the destructible sludge, the symmetry line of the longitudinal through cylindrical hole strictly coincides with the longitudinal line of symmetry of the centralizer body. One of the functions of the centralizer for the casing string is the ability to orient the casing in the middle of the well (to center). The number of centralizers installed per casing can reach hundreds of units for one well. The forming rib 2 is configured to have a height less than the diameter of the well into which the centralizer descends. To ensure sufficient rigidity of the centralizer, the forming rib 2 is configured to have a height less than the diameter of the casing. The forming rib 2 is located either parallel to the longitudinal line of symmetry of the centralizer body, or at an angle to the longitudinal line of symmetry of the centralizer body. The location of the forming ribs at an angle to the longitudinal line of symmetry of the body of the centralizer contributes to a better passage of the casing into the well. To destroy large pieces of sludge into smaller pieces from the outside, the centralizer body is additionally equipped with at least one sludge-destroying rib 3. To ensure better the destruction of the fragments of the cuttings cuttings sludge-destroying rib 3 is made pointed from the outside. Sludge-destroying rib 3 is located along the body of the centralizer and is located between two adjacent forming ribs. Moreover, it can be located either parallel to the longitudinal line of symmetry of the body of the centralizer, or at an angle to the longitudinal line of symmetry of the body of the centralizer, which can be no more than 90 °. The best effect of sludge destruction is achieved when the sludge-destroying rib 3 is located in the middle of the distance between two adjacent forming ribs and at an angle to the longitudinal line of symmetry of the centralizer body of 25 °.

The advantages of the proposed technical solution:

1. Helps to obtain the necessary type of contact "casing - cement - rock" and, accordingly, increases the quality of fastening of the casing (cementing) as a whole;

2. Reduces the likelihood of accidents in general.

Claims

Utility Model Formula

1. A centralizer for a casing string, comprising a centralizer body, comprising, inside, a longitudinal through cylindrical hole, the line of symmetry of which coincides with the longitudinal line of symmetry of the centralizer body, and on the outside, at least three forming ribs located along the centralizer body, characterized in that outside the centralizer body is additionally equipped with at least one sludge-destroying rib, which is made pointed from the outside and located along the centralizer body.

2. The casing centralizer according to claim 1, characterized in that the forming rib is configured to have a height less than the diameter of either the casing or the well into which the centralizer descends.

3. The casing centralizer according to claim 1, characterized in that the forming rib is either parallel to the longitudinal line of symmetry of the centralizer body, or at an angle to the longitudinal line of symmetry of the centralizer body.

4. The casing centralizer according to claim 1, characterized in that the sludge-destroying rib is either parallel to the longitudinal line of symmetry of the centralizer body, or at an angle to the longitudinal line of symmetry of the centralizer body, which can be no more than 90 °, preferably 25 °.

5. The centralizer for the casing according to claim 1, characterized in that the sludge-destroying rib is located between two adjacent forming ribs, mainly in the middle.