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CA1300002C - Adjustable and retrievable multiple point steam injection system - Google Patents

Adjustable and retrievable multiple point steam injection system

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Publication number
CA1300002C
CA1300002C CA000548407A CA548407A CA1300002C CA 1300002 C CA1300002 C CA 1300002C CA 000548407 A CA000548407 A CA 000548407A CA 548407 A CA548407 A CA 548407A CA 1300002 C CA1300002 C CA 1300002C
Authority
CA
Canada
Prior art keywords
casing
tubing string
steam
tubing
uphole
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA000548407A
Other languages
French (fr)
Inventor
Brian George Buchanan
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shell Internationale Research Maatschappij BV
Original Assignee
Shell Internationale Research Maatschappij BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shell Internationale Research Maatschappij BV filed Critical Shell Internationale Research Maatschappij BV
Application granted granted Critical
Publication of CA1300002C publication Critical patent/CA1300002C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

PATENT

HWC:JN

ADJUSTABLE AND RETRIEVABLE MULTIPLE
POINT STEAM INJECTION SYSTEM

Abstract of the Disclosure A single string multipoint injection system comprises a tubing string provided with a static mixer, at least one side pocket mandrel for a wireline set/retrieve outlet orifice valve at each of at least one injection point and a permanent packer means with seal bore extension and seal assembly means arranged to receive a center pocket mandrel for such a valve near the bottom of the tubing string.

Description

PATENT
~-9 1 69 ~3~ HWC: JN

ADJUSTABLE AND RETRIEVA~LE MULTIPLE
5POINT ST~AM INJECTION SYSTEM
Background of the Invention The present invention relates to :injecting steam into a cubterranean reservoir while controlling the proportions that enter selectcd zones of the reservoir. More part:icularly, the invention relates to a single tubing string containing an adjustable downhole regulating system for distributing injected steam between at least two hydraulically isolated zones in an oil well in a manner tending to ensure that the flowline can be retrieved, e.g., for workover or well cleanout operations.
Numerous patents have described steam distribution systems for use in wells. For example, U. S. Patent No. 4,081,028 describes a system for distributing steam among a plurality of intervals, without using packers, by means of deflectors causing the steam to enter the annulus between tubing and casing strings, in directions substantially paralleling the walls of those strings. U S. Patent No. 4,081,032 describes a similar type of steam deflector using a sliding sleeve arrangement for avoiding vortex effects. U. S. Patent No. 4,099,563 describes a steam injecting system utilizing ~ sliding sleeve steam deflector and packer cup means 'for sealing the annular space between the walls of the injection tubing string and the adjacent casing string in locations both above and below the steam deflector. U. S. Patent No.
4,248,302 describes a system utilizing deviated steam injection well containing dual tubing strings and side pocket mandrels for through-the-flowline-installed orifice regulators to control steam injection rates into selected zones of the reservoir. U. S. Patent No. 4,399,865 describes a steam injection system using concentric t~bing strings with one element for deflecting the steam from one string into the surrounding annulus in one location and another for deflecting steam from the other Gtring into the annulus in a different location.

~o~

Summary of the Invention The present invention relates to an impro~ement in a process for injecting controlled amounts of steam into a subterr~oean reservoir formation through a cased well having perforations opening into the reservoir in at least one location uphole from the farthest downhole location. A single conduit tubing string is e~tended within the casing and srranged to provide a conduit for injecting ~team ~nd inserting wireline operated flowline service tools. At least one side pocket mandrel is connected into the lowline in at least one uphole location and arranged for receiving a wireline operated choke means and providing means for flowing fluid into the casing/tubing annulus in a direction substantially paralleling the adjacent walls of the conduits. A center set mandrel is connected into the tubing string near the bottom and arranged for receiving a wireline operated choke means and providing means for directing steam into the casing in a direction substantially paralleling the casing wall. Me~ns for accommodating axial expansion of the tubing string and retrievable packer means for closing the tubing/
casing annulus are connected into the tubing string in a location uphole from the farthest uphole casing perforations. A permanent set packer means for closing the tubing/casing annulus is connected to the tubing string abo~e the centerset mandrel but below the farthest downhole side pocket mandrel. The permanent set packer means is provided with locator tubing sealing means for receiving the center set mandrel and sealing around a portion of the tubing string above that mandrel.
As used herein, the terms 'uphole' and 'downhole' refer to toward or away from the wellhead of horizontal and/or slanting wells.

Brief Description of the Drawing Figure 1 i5 a schematic illustration oE a downhole portion of the present injection system installed in a well.

BKAE~531201 ~L3~2~
Figure 2 is a sectional view of a full bore static mixer of a type particularly suitable for use in the present inven~ion.

Description of the Invention The present invention is, at least in part, premised on a discovery that particularly beneficial results are provided by the presently described novel combination of individually known types of well treating methods and devices.
In steaming subterranean oil reservoirs to enhance oil recovery, it is generally desirable to hydraulically separate upper and lower zones of the reservoir interval with respect to fluid flow uphole or downhole in the casingltubing annulus. Casing/tubing annulus packing means are commonly utilized within a perforated casing in order to prevent vertical flow between such zones. Since the injected steam tends to rise upward, and flow along the upper portion of the reservoir, it is often desirable to subsequently reduce the amount of steam being injected into that zone.
It is not uncommon for a steam injection to be interrupted to repair or workover surface or downhole equipment in an injection well.
Such an il~terruption is commonly accompanied by, or preceded by, inflows of granular formation material and other debris into the borehole of the well. In view of this, although equipment i~ available for providing a single conduit tubing string with packers (such as Permatrieve rotation set packers) above a farthest uphole side pocket mandrel and a similar packPr above a similar downhole side pocket mandrel, such a downhole-located retrievable packer is susceptible to becoming unretrievable whendebris enters the borehole through perforations located uphole from the packer.
The present invention avoids such problems and their attendant expensive remedial measures, i.e., redrilling the well or using dual conduit tubing strings, by using permanent packer means :Erom whicll a ~KAE~531201 cenLer set mandrel can be retrieved and after cleanout, re-inserted in spite of an inflow of debris. The present system allows the in~ertion of tubing strings and/or bailing equipment for remo~ing the debris.
In the present system, it is important that the steam injecting tubing string contain a full bore static mixer capable of en~uring that the water which tends to flow down the tubing ~wall becomes intimately mixed with the higher quality steam which tends to flow down the center of the tubing string. This ensures th~t, for example, when wireline set retrievable choke means are emplaced in each of an uphole side pocket mandrel and a downhole center set mandrel, the amouDt of steam injected through each of those mandrels is substantially that estimated by the Grashof's formula Eor calculating the flow rate of saturated steam through an orifice. The capability for doing this regarding the presently described static mixer, in which the cross sectional area of the flow channel is repeatedly doubled and halved, has been demonstrated by field tests. Those tests included uses in steam injecting wells for operating periods of eight months, with steam injection surveys showing the designed split of the amounts of steam entering into each of at least two locations.
It is known that in various reservoirs of heterogeneous permeability, injection profiles can be improved by a limited entry perforation technique. In that technique, an injection well casing is perforated by limiting the diameter and number of holes so that the s of the maximum injection rates of the holes is equal to the total desired injection rate in the well.
The present invention ean be very advantageously used in conjunction with the limited entry technique. For example, applicant has found that, by providing an upper set of limited entry perforations in an upper zone of the reservoir snd a lower set of such perfor?tions in a lower zo~e, and separating the lower zone from the upper zone by means of the permanent packer providing a tubing/casing annulus seal above the center set mandrel of the present Eystem, several important advantages are obtained. The limited entry perforations can be arranged to provide a selected initial rhtio of amounts of steam entry into the upper and lower zones when the side pocket and center ~et ~andrels are free of flow restricting means. Then, when it becomes desirable to decrease the rate of injection into the upper zone without reducing that into the lower zone, the ratio of the pressures applied to the casing perforations in each of those zones csn be changed by restricting the flow through the side pocket mandrel. As known, such a pressure reduction should be sn amount insufficient to reduce the ratio (of the discharge pressure through the perforations to the downhole injection pressure spplied to those perforations) to less than that needed to maintain critical flow conditions through the perforations (e.g. to a value of less than about 0.578). In the present system, this capability is advantageously combined with a capability of being Able to pull the injection tubing string when desired or necessary for workover or cleanout of the well.
Figure 1 shows the~ preferred embodiment of the present invention. A casing 1 is installed and perforated to provide openings into both upper and lower zone6 to be treated within a reservoir interval. A single conduit tubing string steam flowline 2 is installed within the casing. The tubing string is arranged to contain an e~pansion joint 3 and a neutral set retriev~ble thermal packer 4. As known, such an expansion joint and packer can be repl3ced by a neutral set retrievable therma} packer with an integral expansion joint.
A full bore static mixer 5 iB conn~cted into the tubing string below the retrievable packer. In general, such a static mixer can comprise substantiaIly any which is arranged to permit passage of wireline operated flowline tDols snd to provide an adequate homogeni-zation of the gaseous and liquid phases of the injected steam.

A pup joint 6 connects a side pocket mandrel 7 into the tubingstring. The side pocket mandrel should be arranged to receive wireline set-retrieva~le downhole tools for controlling the rate of flow through the mandrel and should be arranged for directing steam th~t flows through the mandrel in a downward direction, or in a direction a~ least substantially paralleling the adjacent walls defining the tublng~casing annulus .
A tubing section 8 connects into the tubing string a permanent packer 9, which is arranged to provide high temperature seals and a seal bore extension provided with a locator tubing seal assembly 10.
A tubing section 11 connects to the tubing string a center set mandrel 12, which is located at, or near, the bottom of the string. The center set mandrel is arranged to receive wireline set/retrievable downhole orifice controlling toois and to discharge steam flowing through it into a direction at least substantially parallel to the adjacent walls of the casing.
The wireline operated orifice modifying tools utilized in the present system can comprise modified standard wireline set/retrievable gas lift valve bodies. Modification needed for such vslves comprises removing the valve assembly and inserting an orifice plate in its place.
Preferably, the valve body i8 also shortened on the downstream side of the choke in order to minimize pressure loss due to friction.
Figure 2 shows an enlarged section of a static mixer 5 of a type preferred for use in the present invention. As rhown, the mixer comprises a séction of heavy walled pipe in which the cross sectional flow area i8 repeatedly substantially doubled and then Rubstantially halved, for example, by providing alternating internal diameter sections 5A of 2.8-inches, and 5B of 2.0-inches. Static mixers having such a type and size, with at least two alternations of doubled and halved cross sectional areas, were used in the tests described above.

BK~E8531201

Claims (6)

1. In a process for injecting steam through a cased well having casing perforation opening into a subterranean reservoir formation, an improved method for distributing the amount of steam being injected into, respectively, at least one uphole location and one farthest downhole location, comprising:
extending a single conduit tubing string within the casing to provide a conduit for injecting steam and inserting wireline operated tools;
connecting within the tubing string, in at least one relatively uphole location, a side pocket mandrel arranged for receiving a wireline operated throttling valve means and flowing fluid into the tubing/casing annulus in a direction substantially paralleling the adjacent walls;
connecting into the tubing string, at or near its bottom, a center set mandrel arranged for receiving wireline operated flow restricting valve means and flowing fluid into the casing in a direction substantially parallel to the adjacent casing wall;
connecting into the tubing string, expansion means for accommodating axial expansion, a retrievable packer means for closing the tubing/casing annulus in a location uphole from the farthest uphole casing perforations; and connecting into the tubing string a permanent set packer means for closing the tubing/casing annulus above the center set mandrel but below the farthest downhole side pocket mandrel and providing said packer with locator tubing sealing means for receiving the center set mandrel and tubing string and sealing the annulus between it and a portion of the tubing string above the center set mandrel.
2. The process of Claim 1 in which static mixing means for mixing flowing liquid phases is connected into the tubing string and provided with a cross sectional area that is repeatedly doubled and halved while leaving an opening at least sufficient for passage of wireline operated tools, in a location uphole from the farthest uphole side pocket mandrel.
3. The process of Claim l in which the casing perforations are arranged to provide a total effective opening area such that the ratio of the reservoir pressure to the injected pressure adjacent to each perforation is conducive to a critical steam velocity through the perforation that at least substantially equals the velocity of sound in the steam, and thus effectively limits the rate of the steam flow through the perforation.
4. A steam injection system for injecting steam into a subterranean reservoir through a cased well containing at least one casing perforation in each of at least one uphole and one farthest downhole location, comprising:
a tubing string disposed within the casing to provide a conduit for injecting steam through which wireline operated tools can be inserted;
at least one side pocket mandrel connected into the tubing string in at least one uphole location and arranged for receiving wireline operated outflow throttling means and for outflowing fluid into the tubing/casing annulus in a direction at least substantially paralleling the adjacent conduit walls;
a center set mandrel connected into the tubing string at least near the bottom of the string, for receiving wireline operated outflow throttling means and outflowing fluid into the casing in a direction substantially paralleling the adjacent casing wall, conduit expansion means for accommodating thermal expansion of the tubing string and retrievable packer means for closing the tubing/casing annulus connected in and around the tubing string in a location uphole from the farthest uphole casing perforations; and a permanent set packer means for closing the tubing/casing annulus above the center set mandrel and below the farthest downhole side pocket mandrel provided with locator tubing sealing means for receiving the center set mandrel and tubing string and sealing the annulus between it and a portion of the tubing string above the center set mandrel.
5. The system of Claim 4 in which a static fluid mixing means having a cross sectional area which is repeatedly substantially doubled and substantially halved to an extent capable of substantially homogeneously mixing liquid and gaseous phases of steam traveling within the tubing string is connected into the tubing string uphole from the farthest uphole side pocket mandrel.
6. The system of Claim 4 in which the casing perforations have an effective total opening area such that the ratio of the reservoir pressure to the pressure adjacent each perforation is conducive to a velocity of steam flow through the perforation that, at least substantially equals the velocity of sound in the steam and thus effectively limits the rate of flow of the steam through the perforation.
CA000548407A 1986-10-06 1987-10-01 Adjustable and retrievable multiple point steam injection system Expired - Fee Related CA1300002C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US915,587 1978-06-15
US91558786A 1986-10-06 1986-10-06

Publications (1)

Publication Number Publication Date
CA1300002C true CA1300002C (en) 1992-05-05

Family

ID=25435970

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000548407A Expired - Fee Related CA1300002C (en) 1986-10-06 1987-10-01 Adjustable and retrievable multiple point steam injection system

Country Status (1)

Country Link
CA (1) CA1300002C (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101787875A (en) * 2009-12-29 2010-07-28 中国石油天然气集团公司 Quantitative injection method of multi-level injection liquid
CN102536183A (en) * 2012-01-31 2012-07-04 中国石油化工股份有限公司 Underground gas injection pipe column
CN107401399A (en) * 2017-08-29 2017-11-28 中国石油天然气股份有限公司 Adjustable steam injection column
WO2018184093A1 (en) * 2017-04-04 2018-10-11 Interra Energy Services Ltd. Methods and apparatuses for steam injection in wellbores for hydrocaron recovery
CN110344787A (en) * 2019-07-16 2019-10-18 胜利方兰德石油装备股份有限公司 A kind of pumping unit system with multistage steam injection packer accessory

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101787875A (en) * 2009-12-29 2010-07-28 中国石油天然气集团公司 Quantitative injection method of multi-level injection liquid
CN101787875B (en) * 2009-12-29 2014-01-01 中国石油天然气集团公司 Quantitative injection method of multi-level injection liquid
CN102536183A (en) * 2012-01-31 2012-07-04 中国石油化工股份有限公司 Underground gas injection pipe column
WO2018184093A1 (en) * 2017-04-04 2018-10-11 Interra Energy Services Ltd. Methods and apparatuses for steam injection in wellbores for hydrocaron recovery
CN107401399A (en) * 2017-08-29 2017-11-28 中国石油天然气股份有限公司 Adjustable steam injection column
CN110344787A (en) * 2019-07-16 2019-10-18 胜利方兰德石油装备股份有限公司 A kind of pumping unit system with multistage steam injection packer accessory

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