CN104563953A - Double-layer steel pipe expansion type pipe external casing packer - Google Patents

Abstract

The invention relates to a double-layer steel pipe expansion type pipe external casing packer, which comprises an expansion base pipe, a packing unit, an upper joint and a lower joint, wherein the upper joint and the lower joint are processed at the two ends of the expansion base pipe, the packing unit is formed by installing one or more than one packing unit outside the expansion base pipe at intervals, each packing unit comprises an expansion outer pipe, upper and lower fixed pup joints and a rubber tube, the upper and lower fixed pup joints are connected with the two ends of the expansion outer pipe, the rubber tube is connected with the outer part of the expansion outer pipe, the expansion base pipe and the expansion outer pipe respectively adopt expansion steel pipe materials, the upper and lower ends of the expansion outer pipe are connected onto the expansion base pipe through the upper and lower fixed pup joints, and a pre-set expansion cavity is formed between the expansion outer pipe and the expansion base pipe. The external casing packer has the advantages that through the expansion of a double-layer steel pipe, the tight attachment of the steel pipe and the rubber tube to the ground layer is realized, the advantages of great packing outer diameter of the packer, high intensity, capability of complying with the well hole packing and the like are realized, and the external casing packer can be widely used in the fields of well completion such as segmented well completion and inter-layer packing.

Description

Double-layer steel pipe expandable external packer

technical field

The invention relates to the field of drilling and completion tools, in particular to provide a double-layer steel pipe expansion type external packer for segmented well completion and interlayer isolation.

Background technique

The outer pipe packer is an important tool in the process of petroleum cementing and selective well completion. It is connected with the casing and is a downhole tool used to seal the annular space between the casing and the well wall. Implement layer separation, it can carry out operation and production control according to layer, so as to effectively realize the segmented production of oil and gas wells and the interlayer isolation of complex formations.

The existing outer casing packer mainly realizes outer casing sealing by two methods of rubber sleeve expansion sealing and self-expansion when encountering oil and water. The expansion sealing method of the rubber sleeve, through the action of the high-pressure fluid entering the expansion cavity of the rubber sleeve, makes the packer expand and deform and closely contact with the well wall to form a seal, thus realizing sealing and separating the annular space. The hydraulic expansion type external packer usually uses drilling fluid as the expansion medium, and it is easy to seal failure in complex downhole environments such as high temperature and high pressure, and casing eccentricity; the cement slurry expansion type external packer uses cement slurry as the expansion medium. However, its construction technology is relatively complicated, causing serious construction accidents; oil/water self-expanding tubular packer adopts oil/water self-expanding rubber, which expands after encountering oil/water in the later stage to seal formation, but its sealing effect is limited under high temperature and high pressure conditions, and the sealing strength of rubber after self-expansion is also limited, making it difficult to seal complex formations.

Conventional outer casing packers have been widely used in the field of petroleum well completions to perform staged screen completion and interlayer isolation, protect and reduce oil layer pollution, and delay horizontal bottom water coning to a certain extent; but There are still problems such as limited sealing effect, fragile sealing rubber, and short sealing time.

Contents of the invention

The purpose of the present invention is to solve the shortcomings of the existing casing outer packer technology by expanding the sealing rubber cylinder to provide a double-layer steel pipe expansion type outer packer. It expands to make the steel pipe and rubber tube close to the formation. It has the advantages of large outer diameter of isolation, high strength, and ability to adapt to wellbore isolation. It can be widely used in well completion fields such as staged well completion and interlayer isolation.

The present invention is achieved like this:

Double-layer steel pipe expandable external packer, including expansion base pipe, isolation unit, upper joint and lower joint, the two ends of the expansion base pipe are processed with upper joint and lower joint, wherein: the isolation unit consists of one or The above isolation units are arranged outside the expansion base pipe at intervals, and each isolation unit includes an expansion outer pipe, upper and lower fixed joints connected to both ends of the expansion outer pipe and a rubber tube connected to the outside of the expansion outer pipe; the expansion base pipe and the expansion The outer tubes are all made of expandable steel pipes, and the upper and lower ends of the expanded outer tubes are connected to the expanded base pipe through upper and lower fixed nipples, and an expansion chamber is preset between the expanded outer tube and the expanded base tube.

The above program also includes:

Liquid is injected into the expansion cavity.

The two ends of the expansion outer tube are respectively connected with the upper and lower fixed sub-joints through connecting sub-joints. An expandable sealing ring is provided on the outer side of the expansion base pipe with the same section as the connecting sub-joints, and liquid inlet holes are radially processed on the upper fixed sub-joints.

The sealing ring is made of a metal material with certain elongation, and is processed into an annular structure.

The wall thickness of the expanded outer tube is thinner than that of the expanded base tube, and its shape includes a circular tube or a corrugated circular tube.

The rubber cylinder is one or more sections, and the sealing rubber used is directly vulcanized on the outer surface of the expansion outer tube, or embedded and processed on the outside of the expansion outer tube, or self-expanding rubber in contact with oil/water is used.

The advantages of the present invention are:

(1) Through the expansion of the double-layer steel pipe, the steel pipe and the rubber cylinder are tightly sealed against the formation, and the concept of the expansion pipe is introduced into the outer pipe packer. ability.

(2) The invention depends on the expansion of the double-layer steel pipe, and the rubber tube also expands accordingly. Therefore, the invention has a larger outer diameter after expansion, and the range of the annular space of the isolated wellbore is larger, and it can be closely attached to the wellbore compliance well At the same time, the length and quantity of the isolation unit can be adjusted to improve the isolation effect.

(3) The rubber retraction phenomenon will not occur after the expansion seal of the present invention, and the isolation time is long, which is suitable for the fields of screen segment completion, expansion screen completion, selective completion and interlayer isolation.

Description of drawings

Fig. 1 Schematic diagram of a double-layer steel pipe expandable external packer

Fig. 2a Schematic diagram of the isolation unit when the liquid inlet hole is closed by expansion

Fig. 2b Schematic diagram of the expansion of the isolation unit

Fig. 2c Schematic diagram of the inflated isolation unit

Fig. 3 Schematic diagram of the structure of the external packer after expansion and setting

In the figure: 1. Expansion base pipe, 2. Expansion outer pipe, 3. Connecting sub, 4. Upper fixed sub, 5. Lower fixed sub, 6. Rubber tube, 7. Expandable sealing ring, 8. Upper joint , 9. Lower joint, 10. Inlet hole 11. Inner tube, 12. Variable diameter expansion tool, 13 Expansion chamber, 14. Packing unit.

Detailed ways

Now in conjunction with the accompanying drawings of the description, the present invention will be further described.

As shown in Figures 1 to 3, a double-layer steel pipe expandable external packer is composed of an expandable base pipe 1, a packing unit 14, an upper joint 8 and a lower joint 9, and the two ends of the expandable base pipe 1 are processed There are an upper joint 8 and a lower joint 9, and the packing unit 14 is mainly composed of an expansion outer tube 2, a connecting sub-joint 3, an upper fixed sub-joint 4, a lower fixed sub-joint 5, a rubber tube 6, a seal 7, a liquid inlet hole 10 and Expansion cavity 13 etc. constitute. Both the expansion base pipe 1 and the expansion outer pipe 2 are made of expandable steel pipe material, and the expansion outer pipe 2 is thinner than the expansion base pipe 1, so it is easier to realize hydraulic expansion, and its shape can be a round pipe or a corrugated round pipe Isotropic tubes. The expansion outer pipe 2 is located outside the expansion base pipe 1, the upper end is fixedly connected to the expansion base pipe 1 through the connection nipple 3 and the upper fixing nipple 4, and the lower end is connected to the expansion base pipe 1 through the connection nipple 3 and the lower fixing nipple 4 . An expansion sealing ring 7 is processed on the outer surface of the expansion base pipe 1 having the same radial section as the connecting short joint 3, and the expansion sealing ring 7 can be made of a metal material with certain elongation properties and made into a ring structure. The upper fixed sub-joint 4 and the lower fixed sub-joint 5 are respectively located at both ends of the isolation unit 14, and are made of expandable materials, which can expand simultaneously with the expansion base pipe 1. The liquid inlet hole 10 is processed, and the lower fixed joint 5 does not process the liquid inlet hole 10 .

As shown in Fig. 1 and Fig. 2a, when the tool is lowered into the well, the predetermined position on both sides of the formation needs to be isolated, and the liquid in the well enters between the expanded base pipe 1 and the expanded outer pipe 2 through the liquid inlet hole 10 of the upper fixed nipple 4 ring space. Lower the inner pipe 11 and the variable-diameter expansion tool 12 to both sides of the isolation unit 14, and the variable-diameter expansion tool 12 realizes the diameter reduction under the action of hydraulic pressure. The diameter reduction method can be the roller expansion method or the cone closure method. When the diameter-reducing expansion tool 12 realizes the diameter reduction, the expansion base pipe 1 is promoted to expand accordingly. The variable-diameter expansion tool moves from top to bottom under the cooperation of hydraulic pressure and machinery, so that the radial deformation of the expansion base pipe 1 extends in the axial direction. When the expansion base pipe 1 expands to the expansion sealing ring 7, the expansion sealing ring 7, which is not in contact with the connecting short joint 3, also expands accordingly, and its outer diameter increases, and the ring is close to the expansion base pipe 1 and the connecting short. Between the joints 3, a metal seal is formed to close the liquid inlet hole 10, so that the annular space between the expansion base pipe 1 and the expansion outer pipe 2 forms a hydraulic expansion chamber 13. It is worth mentioning that the upper fixed sub-joint 4 may not be processed with the liquid inlet hole 10, and the liquid is injected into the expansion chamber 13 between the pre-expanded base pipe 1 and the expanded outer pipe 2 to form a sealed expansion chamber 13 in advance. When 1 expands, the extrusion expansion of the liquid to the expansion outer tube 2 is realized.

As shown in Figure 2b, after the liquid inlet hole 10 on the upper fixed nipple 4 is closed, the variable diameter expansion tool 12 continues to move downward, and the expansion base pipe 1 gradually completes expansion, and the space of the expansion chamber 13 tends to be compressed. However, since the expansion cavity 13 is filled with incompressible liquid, the liquid in the expansion cavity 13 will inevitably promote the expansion of the relatively more deformable expansion outer tube 2, so that the sealing rubber tube 6 processed on the outer surface of the expansion outer tube 2 is squeezed. Press into the formation until the expansion and setting of the entire isolation unit 14 is completed. The expansion sealing ring 7 at the lower part of the isolation unit 14 is also expanded to form a metal seal with the corresponding external joint 3, which enhances the sealing performance of the liquid in the expansion chamber 13 after the isolation unit 14 is expanded, so that the liquid in the expansion chamber 13 cannot Outflow prevents rebound or shrinkage of the outer tube 2 and sealing rubber cylinder 6 under the action of formation pressure in the later stage of expansion.

As shown in Fig. 2c and Fig. 3, when the variable-diameter expansion tool 12 expands the expanded base pipe 1, the expansion set-up of all the isolation units 14 is also completed to realize interlayer isolation. When the present invention is used in conjunction with conventional casing pipes, screen pipes, etc., after the expansion is set, the expansion base pipe 1 near the upper joint 8 and the lower joint 9 does not expand partially, resulting in a deformation with small ends and a large middle. Diameter shape; when the present invention is used in conjunction with subsequent expansion products such as expansion sleeves and expansion screens, the entire expansion base pipe 1 will be fully expanded.

In the present invention, through the expansion of the double-layer steel pipe, the isolation unit 14 has a larger outer diameter, and the range of the annulus of the isolated wellbore is larger, and can be closely attached to the wellbore and conform to the wellbore wall to achieve expansion of the outer pipe 2 and The rubber cylinder 6 is tightly sealed to the formation, and the isolation strength is obviously higher than that of the conventional simple rubber cylinder 6. At the same time, the length and quantity of the isolation unit 14 can be adjusted to improve the isolation effect.

The rubber cylinder 6 will not shrink back after the swelling seal, effectively improves the packing strength and prolongs the packing time, has the advantages of large packing outer diameter, high strength, and can comply with wellbore packing, etc., and can effectively Isolate oil, gas and water layers, perform selective production or block a certain interval, and ensure the sealing of the casing outer annulus. It can be widely used in screen completions, expansion screen completions, and selective completions. and interlayer isolation and other well completion fields.

Claims (5)

1. double-layer pipe expansion type external pipe packer, comprise expansion base tube, packing units, top connection and lower contact, expansion base tube two ends are processed with top connection and lower contact, it is characterized in that: described packing units is located at the outside of expansion base tube by one or more packing units intervals, each packing units comprises expansion outer tube, be connected to fixing pipe nipple up and down and being connected to the rubber tube of expansion outside pipe of expansion outer tube two ends; Expansion base tube and expansion outer tube all adopt expandable steel tubular material, and the upper and lower side of expansion outer tube is connected on expansion base tube by fixing pipe nipple up and down, presets expansion chamber between expansion outer tube and expansion base tube.

2. double-layer pipe expansion type external pipe packer according to claim 1, is characterized in that: inject liquid in expansion chamber.

3. double-layer pipe expansion type external pipe packer according to claim 1, it is characterized in that: at expansion outer tube two ends respectively by connecting short section with fix pipe nipple up and down and be connected, connecting short section is provided with expandable sealing ring with outside the expansion base tube in cross section, and on upper fixing pipe nipple, radial direction is processed with inlet opening.

4. double-layer pipe expansion type external pipe packer according to claim 3, is characterized in that: described joint ring adopts the metal material with certain extension property, and is processed as loop configuration.

5. the double-layer pipe expansion type external pipe packer according to claim 1,2,3 or 4, is characterized in that: expansion outer tube relative expansion base tube wall thickness is thinner, and its shape comprises pipe or waveform pipe; Described rubber tube is one or more snippets, and the direct sulfuration of caulking gum of employing is at the outer tube outer surface of expansion, or embedded processing is outside expansion outer tube, or adopts chance oil/chance water self-expanding rubber.