AU3337601A

AU3337601A - Zero drill completion and production system

Info

Publication number: AU3337601A
Application number: AU33376/01A
Authority: AU
Inventors: Steve Geste; Kyle Graves; Ray Vincent
Original assignee: Baker Hughes Inc
Current assignee: Baker Hughes Holdings LLC
Priority date: 2000-03-30
Filing date: 2001-03-30
Publication date: 2001-10-04
Anticipated expiration: 2021-03-30
Also published as: GB2360802B; CA2342657A1; NO20011609L; NO323289B1; CA2342657C; GB0107764D0; AU783553B2; GB2360802A; NO20011609D0

Description

P/00/0o11 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: Zero drill completion and production system The following statement is a full description of this invention, including the best method of performing it known to us: Freebjills Carter Smith BeadleMELC601O85009.3 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to petroleum production wells. More particularly, the invention relates to well completion and production methods and apparatus.

2. Description of the Prior Art The process and structure by which a petroleum production well is prepared for production involves the steps of sealing the production zone from contamination and securing production flow tubing within the well borehole. These production 10 zones are thousands of feet below the earth's surface, Consequently, prior art procedures for accomplishing these steps are complex and often dangerous. Any S. i procedural or equipment improvements that eliminate a downhole "trip", is usually a welcomed improvement.

**Following the prior art, production tube setting and opening are separate "trip" events. First, the wall casing liner is secured by cementing the production string is then positioned where desired within the borehole and the necessary sealing packers set by fluid pressure internally of the tubing bore. After the packers are set, a cementing circulation valve in the production tube assembly is opened by tubing bore pressure and annulus cement is pumped into position around the production tubing and above the production zone upper seal packer.

This procedure leaves a section of cement within the tubing below the cementing valve that blocks the upper tubing.bore from production flow. The blockage is between the upper tubing bore and the production screen at or near the terminal end of the tubing string, Pursuant to prior art practice, the residual cement blockage is usually removed by drilling. A drill bit and supporting drill string must be lowered into the well, internally of the production tubing, on a costly, independent "trip" to cut away the blockage.

SUMMARY OF THE INVENTION An objective of the present invention is to position well production tubing Swithin the wellbore, secure the tubing in the well by cementing, and open the tubing i 10 to production flow in one downhole trip. In pursuit of this and other objectives to hereafter become apparent, the present invention includes a production tubing string having the present well completion tool assembly attached above the production screen and casing shoe.

This completion tool assembly includes an alignment of four basic tools in serial downhole order. At the uphole end of the alignment Is a pressure actuated cementing valve followed by an external casing packer. Below the casing packer is a pressure actuated production valve and below the production valve is a bore plug landing collar With the tubing string downhole and the open hole production screen located at the desired position within the well production zone, an opening plug is deposited in the tubing bore at the surface and pumped by water, other well fluid or finishing cement down against the plug landing collar. Upon engaging the landing collar, the plug substantially seals the tubing bore to facilitate dramatic pressure increases therein. Actuated by a pressure increase within the tubing bore column, the external casing packer is expanded to block the borehole space annulus between the raw borehole wall and the packer body. An additional increase in pressure slides the opening sleeve of the pressure activated cementing valve into alignment of the internal and external circulation ports. Upon alignment of the circulation ports, tubing bore fluid such as cement is discharged through the ports into the wellbore annulus space. Due to the presence of the expanded external casing packer below the circulation ports, the annulus cement must flow up-hole an around the tubing 10 above the packer.

When the desired quantity of cement has been placed in the tubing bore at the surface, the fluidized cement within the tubing bore column is capped by a

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1 closing pump-down plug. Water or other suitable well fluid is pumped against the closing plug to drive the remaining annulus cement through the circulation ports. At 15 the circulation port threshold, the closing plug engages a plug seat on the closing sleeve of the pressure actuated cementing valve. With a first pumped pressure increase acting on the closing plug seat, the cementing valve closing sleeve slides into a circulation port blocking position. A second pressure increase that is normally greater than the first develops a force on the plug seat of such magnitude as to shear the seat ring retaining screws. When structurally released from the valve closing sleeve, the closing plug and plug seat impose a piston load on the short cement column supported by the opening plug and plug landing collar. This column load is converted to fluid pressure on the pressure activated production valve to force a fluid flow opening through the valve, When the pressure activated production valve opens, the residual cement column is discharged through the open valve below the packer.

Although the residual cement column is discharged into the production zone bore, the absolute volume of cement in the column is dispersed as insignificant, As the closing plug is driven by the finishing fluid through the central bore of the production valve past the valve opening, the finishing fluid, water or light solvent, rushes through the valve opening to flush It of residual cement and debris. At this 10 point, a clear production flow path from the production zone into the production tubing bore is open. When pressure on the finishing fluid is released, upflowing production fluid sweeps the residual finishing fluid out of the tubing bore ahead of the production fluid flow.

BRIEF DESCRIPTION OF THE DRAWINGS A detailed description of the invention following hereafter refers to the several figures of the drawings wherein like reference characters in the several figures relates to the same or similar elements throughout the several figures and: FIG. 1 is a schematic well having the present invention in place for completion and production; FIG. 2 is a partial section of the present well completion tool assembly in the run-in condition; FIG. 3 is a partial section of a pressure actuated cementing valve; FIG. 4 is a partial section of the present well completion tool assembly in the packer inflation condition; FIG. 5 is a partial section of the present well completion tool assembly in the annulus cementing condition; FIG. 6 is a partial section of the present well completion tool assembly in the cement termination condition: FIG. 7 is a partial section of the present well completion tool assembly in the 0 production flow opening condition,

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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The invention utility environment is represented by the schematic of FIG. 1 which illustrates a well bore 10 that is normally initiated from the earth's surface in a vertical direction. By means and procedures well known to the prior art, the vertical well bore may be continuously transitioned into a horizontal bore orientation 11 as Sdesired for bottom hole location or the configuration of the production zone 12.

Usually, a portion of the vertical surface borehole 10 will be internally lined by steel casing pipe 14 which is set into place by cement in the annulus between the inner borehole wall and the outer surface of the casing 14.

Valuable fluids such as petroleum and natural gas held within the production zone 12 are efficiently conducted to the surface for transport and refining through a string of production tube 16. Herein, the term "fluid" is given its broadest meaning to include liquids, gases, mixtures and plastic flow solids. In many cases, the annulus between the outer surface of the production tube 16 and the inner surface of the casing 14 or raw well bore 10 will be blocked with a production packer 18. The most frequent need for a production packer 18 Is to shield the lower production zone 12 from contamination by fluids drained along the borehole 10 from higher zones and strata, The terminal end of a production string 16 may be an uncased open hole but is often equipped with a liner or casing shoe 20 and a production screen 22. In lieu of a screen, a length of drilled or slotted pipe may be used. The production screen 10 22 is effective to grossly separate particles of rock and earth from the desired fluids carried by the formation 12 structure and admit the production zone fluids into the inner bore of the tubing string 16. Accordingly, the term "screen" is used expansively herein as the point of well fluid entry into the production tube.

Pursuant to practice of the present invention, a production string 16 is provided with the present well completion tool assembly 30. The tool assembly Is positioned in the uphole direction from the production screen 22 but closely proximate therewith. As represented by FIG. 1, the production packer 18 (if necessary), the completion tool assembly 30, the production screen 22 and the casing shoe 20 are preassembled with the production tube 16 as the production string is lowered into the wellbore With respect to FIG. 2, the completion tool assembly 30 comprises a pressure activated cementing valve 32, an external casing packer 34, a pressure activated production valve 36 and a plug landing collar 38. Each of these devices may be known to those of ordinary skill in some modified form or applied combination.

As shown in greater detail by FIG. 3, the pressure actuated cementing valve provides circulation ports 40 and 42 between the inside bore of the tool and the outer tool casing. The inner circulation ports 42 are through an axially sliding sleeve 44. The sleeve is axially positioned to misalign the inner ports 42 from communication with the outer ports 40 for a well run-in setting. Down-hole, the sleeve is positionally displaced by a predetermined high fluid pressure within the 10 inside bore of the tool from the closed, run-in setting to a position at which the inside and outside ports are aligned. When aligned, well cement may be pumped from within the internal bore of the tool and tubing string through the ports 40 and 42 into the well annulus around the tubing string. Use of the term "cement" herein is intended to describe any substance having a fluid or plastic flow state that may be pumped Into place and thereafter induced to solidify.

Closure of the port 40 and 42 communication is accomplished by a second sliding sleeve 46 having a plug landing seat 48 secured thereto by shear screws 49.

Procedurally, the cement slurry tail is capped by a wiper closing plug. The closing plug is pumped by water or other suitable well working fluid down the tubing string bore until engaging the plug landing seat 48. When the plug engages the seat 48, fluid pressure in the bore may be increased to 1000 psi, for example, against the plug and seat 48 until the closing sleeve 46 slides to the port 40-42 closure position, Additional pressure against the closing plug and seat 48, 5000 psi, for example, is operative to shear the assembly screws 49 and drive the plug and seat out of the tool bore.

The external casing packer 34 is any device that creates a seal in the wellbore annulus around the tube string. A common example of a casing packer provides an expansible elastomer boot around an internal tube body. An internal bore of the tube body is coaxially connected with the production tube string. The expansible boot is secured to the tube body around the perimeter of the two circumferential edges. A fluid tight chamber is thereby provided between the tube 10 body and the inside surface of the expansible boot, This chamber Is connected by a check valve controlled conduit to the interior bore of tube body. Hence, pressurized fluid within tube body expands the boot against the casing or borehole wall.

4 The pressure actuated production valve 36 is a coupling device having an internal sleeve radially spaced inwardly from the exterior jacket to define a fluid flow e annulus between the interior wall of the valve jacket and the exterior wall of the sleeve, This flow annulus is linked to the interior bore of the valve by pressure displaced structure such as a pressure ruptured disc or reed to effect a single acting flow connection.

The plug landing collar 38 is an extension of the production valve sleeve that continues an open flow continuity with the production valve annulus. Internally of the landing collar is a pump-down plug seat.

The above described tubing string assembly is lowered into the well bore with the packers 18 unset and the external casing packer 34 deflated, The cementing valve 32 ports 40 and 42 are closed. The production flow screen 22 is positioned where desired and an opening pump-down plug 50 is placed in the tubing string bore to be pumped by well finishing cement down to seating engagement with the landing collar 38. If desired, the plug 50 may also be transferred downhole by water or other well working fluid. With the plug 50 secure upon the landing collar plug seat 38, fluid pressure within the tubing bore is Increased against the opening plug 50 to inflate the packer 34. This event blocks the well annulus between the production screen 22 and the cementing valve 32.

10 Next, fluid pressure within the tubing bore is further increased to shift the opening sleeve 44 and align the circulation ports 40 and 42. When the circulation ports align, cement flows through the ports and up the borehole annulus around the production tubing.

The total cement volume requirement for a particular well is usually calculated with considerable accuracy. Accordingly, when the desired quantity of cement has been pumped into the tubing bore, a closing pump-down plug 54 is placed in the bore to cap the cement column. Behind the closing pump-down plug 54, water or other suitable well working fluid is pumped to complete the cement transfer and settle the closing pump-down plug 54 against the cementing valve plug seat 48. An increase of tubing bore pressure to 1000 psi, for example, against the plug 54 and seat 48 causes a shift in the valve closing sleeve 46 thereby closing the fluid communication ports 40 and 42. Thereafter, the tubing bore pressure is increased again, to 5000 psi, for example, to shear the retaining screws 49 and release both the seat 48 and the closing plug 54. When released, the free piston nature of the plug and seat unit drives against the residual cement column that was isolated between the opening pump-down plug 50 and the closing pump-down plug 54, Pressure against the closing pump-down plug 54 is thereby transferred to the residual cement column and consequently to the pressure activated production valve 36. This pressure permanently opens the flow port between a production flow annulus and the tubing bore. Continued pressure against the residual cement column purges the residual cement through the newly opened production valve into 10 the well bore below the packer 34, At this point, the well completion process is essentially complete and the well is ready to produce. However, some operators may choose to transfer a cement contamination fluid into the production zone bore the assure a subsequent removal of the residual column cement from the well bore.

Having fully described the preferred embodiments of the present invention, various modifications will be apparent to those skilled in the art to suit the circumstances of a particular well and manufacturing capacity. It Is intended that all variations within the scope and spirit of the appended claims be embraced by the foregoing disclosure.

It will be understood that the term "comprises" or its grammatical variants as used herein is equivalent to the term "includes" and is not to be taken as excluding the presence of other elements or features.

Claims

2. A method of completing a well comprising the steps of: 2 a) assembling a well fluid production string comprising a pressure 3 activated cementing valve, an external casing packer, a pressure activated 4 production valve and a plug seal operatively combined with production tubing, S 5 said plug seal being positioned between said production valve and a point of 6 well fluid entry into said production tubing; 7 b) positioning said point of well fluid entry within said well at a desired 8 well fluid production location; 9 c) delivering a pump-down plug into said plug seal; d) increasing fluid pressure within said production tubing to inflate said 11 external casing packer; 12 e) increasing fluid pressure within said production tubing to open said 13 pressure activated cementing valve; 14 f) pumping a desired quantity of borehole cement down said tubing and through said open cementing valve; 16 g) delivering a closing pump-down plug against said pressure activated 17 cementing valve to close said cementing valve; 18 h) increasing fluid pressure within said production tubing to open said 19 production valve; 20 i) displacing said closing pumpedown plug from obstructing a flowpath 21 through said production valve; and 22 j) producing well fluid through said production tube. .1 3 A method of completing a well as described in claim 2 wherein said 2 production string assembly further comprises a production packer positioned up- 3 hole from said cementing valve. 1 4. A well completion tool comprising the combination of: 2 a) a pressure activated cementing valve; 3 b) a well annulus barrier; 4 c) a pressure activated production valve; and d) a plug seal, 1 5. A well completion tool as described in claim 4 wherein said cementing valve, 2 a well annulus barrier, production valve and plug seal are serially aligned toward the 3 well bottom. 1 6. A well completion tool as described in claim 4 wherein said combination 2 further comprises a production packer positioned up-hole from said cementing 3 valve. 1 7, A well production string comprising a production tube in operative assembly 2 with: 3 a) a pressure activated cementing valve; 4 b) a well annulus barrier 5 c) a pressure activated production valve; and 6 d) a plug seal. 1 8. A well production string as described in claim 7 further comprising a 2 production packer positioned up-hole from said cementing valve. 1 9, A well production string as described in claim 7 further comprising a well fluid 2 production screen operatively disposed down-hole from said plug-seal. BAKER HUGHES INCORPORATED by Freehills Carter Smith Beadle Registered Patent Attorneys for the Applicant March 2001