DUAL DOWNHOLE PRESSURE BARRIER WITH COMMUNICATION TO VERIFY
Apparatus and method are provided for placing a dual pressure barrier in a vertical or horizontal well and verifying by pressure sensors in the well that the pressure barriers are operable. Communication of data from the well may be by electromagnetic or acoustic signals, and the data may be acquired on a ship near the well.
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This application claims priority to Provisional Application Ser. No. 61/683,749 filed on Aug. 16, 2012 and Provisional Application Ser. No. 61/701,317 filed on Sep. 14, 2012.
BACKGROUND OF INVENTION1. Field of the Invention
This application is directed to drilling and completion of wells subsea. More particularly, apparatus and method are provided for decreasing the risk of hydrocarbons flowing from a well after it is drilled and as the well is completed for production.
2. Description of Related Art
Operations for recovering hydrocarbons from beneath the sea have expanded to many areas of the world and to ever deeper water. The drilling of wells in deep water requires large vessels with very large carrying capacity and large platforms for storage of materials and equipment. This means very high operating expenses for the drilling rigs that drill the wells. After a well is drilled subsea, the well must be “completed,” which means placing equipment in the well and at the sea floor to control flow from the well and allow further operations to be conducted in the well. Completion operations can be conducted with smaller, less expensive vessels and smaller rigs. Normally in the development of a subsea hydrocarbon reservoir, multiple wells will be drilled; it is desirable to drill and temporarily abandon each well, moving the expensive drilling rig to drill another well while using a less expensive vessel and rig to complete the first well. Ideally, completion operations may be accomplished by a small ship operating without a riser connecting the ship to the seafloor. During the time that drilling has ceased and before the well is finally ready to be produced, some of the barriers to flow in the well are removed. It is absolutely critical that fluids in zones that have been penetrated by the well be prevented from flowing up the well to the seafloor during this time.
It is commonly required by government regulations that there be at least two pressure barriers in a well at all times to prevent flow up the well. Commonly used barriers during drilling are high-density fluids and blowout preventers at the seafloor. After drilling ceases, pressure barriers are provided by mechanical plugs, packers, valves, cement plugs or other barriers known in industry.
U.S. Pat. No. 7,380,609 discloses a method for suspending, completing or working over a well by placing two pressure barriers deeper in the well than any completion tubing is to be placed in the well. The plugs are in close proximity and are said to be made independently verifiable (that both do not leak) by placement of a pressure gage between the plugs with wireless transmission of data from the gage to above the top plug and then transmission of data to surface by usual methods. U.S. Pat. No. 8,066,975 discloses a remotely actuatable valve to be placed in the bore of a tubing hanger to allow suspension of activities in a well without a dual bore riser to the surface. U.S. Pat. No. 8,082,990 discloses joining assemblies in a well with a communication line using inductive coupling to achieve signal communication across a coupling.
To install completion elements in a well without the use of a drilling rig, riser and BOP, new methods and apparatus are needed to provide at least two verifiable pressure barriers at all times. Furthermore, verification of the pressure barriers should be possible from a vessel in the vicinity of the well. Implementation of a two-barrier system will allow the offshore drilling rig to be moved after drilling operations and installation of lower elements of completion equipment (sand screens, e.g.) has been accomplished, rather than waiting for the well to be completed before moving. Deployment of upper and some lower completion elements can then be accomplished with a lower-cost special purpose vessel more efficiently adapted to completion operations, while maintaining at least two verified pressure barriers in the well at all times. The savings in cost can be millions of dollars per well.
SUMMARY OF THE INVENTIONA dual downhole barrier system having the capability of wirelessly communicating deep well pressures below and between pressure barriers in a well to the surface is provided. An intelligent well suspension plug set in the tubing hanger or casing immediately below the wellhead and capable of communicating data, including pressures and temperatures gathered at locations below the plug, to the surface is provided. A method of deploying the apparatus in a well in a single trip, along with other apparatus such as a liner or sand control screen, is also provided. A separable work string may be employed for running apparatus into a well.
Referring to
An offshore well is illustrated in most of the figures, and the apparatus and method described herein are more likely to be deployed in an offshore well, but they may also be deployed in a land well. Well 10 has been drilled, cased with surface casing 62 and production casing 64 and both casings have been cemented in place, using normal industry procedures. Intermediate casings (not shown) may also be present in the well. Well 10 has Subsea Isolation System 17 in place, which may be a smaller BOP that can be deployed from an ROV rather than the drilling BOP. Plug 30 (often referred to herein as “WiSP” or “Intelligent Well Suspension Plug”) has been placed in the well near or in a tubing hanger or other pack-off equipment 34 near ground level or sea floor 100.
Dual Downhole Barrier System (DDBS) 70 comprises polished bore receptacle 71, retrievable packer 72, secondary isolation barrier valve 73, telemetry sub 16, permanent packer (or liner hanger) 74 and primary isolation barrier valve 75. Second polished bore receptacle 77 may be used to disconnect the tubing between the packers to make operations easier if it becomes necessary to retrieve the upper portion of DDBS 70 after permanent packer 74 is set. Ported sub or sleeve or sliding sleeve 76 may optionally be placed between the packers. Sand screen 78 or other a casing liner may be run in a well below DDBS 70. Alternatively, a tubing-conveyed-type perforating gun (not shown) may be run to perforate a liner. Alternatively, pressure and temperature data may be gathered under each or either of the two barriers. These data may also be transmitted to the surface. The number of channels of data transmitted may be increased to three or more.
WiSP 30 receives signals from probe 25 and from sensor 33. Sensor 33 is used to measure pressure in the casing between DDBS 70 and plug 30. Pressure data may then be transmitted to receiver/transmitter 19 mounted on seafloor completion equipment 17. Two channels of data may be received by communication plug 30 and transmitted to receiver/transmitter 19. Each channel may include pressure data—one from below the DDBS and one from above.
Operators of wells, and usually government regulations, require at least two independent barriers from formation pressure in place at every moment of well operations. Typically, during drilling and completions operations, this is achieved by the combination of a primary barrier, being either a deep set plug and or valve or kill weight completion fluid, combined with the drilling BOP, which provides the second barrier. The system presented herein is provided for the time after the drilling BOP has been removed. Two devices are provided for well barriers. The two barrier devices are completely ‘stand-alone’ and without interdependency in their operations. The lower barrier is the DDBS, described above. A communication plug, which is described below, may be used along with a column of kill weight completion brine as additional barriers. The system elements and components are each designed for full working pressure retention with a safety factor.
DDBS 70 may comprise the same components as explained above and a sand screen or gravel pack (not shown) or other sand control system may be below, as explained above. The means to disconnect the tubing between packers 72 and 74 (
The principal difference in this scenario is that work string 201 (
In operation, pressure and temperature data are measured in telemetry sub 16 and transmitted up the work string to WiSP 30(b), which may be adapted for use of work string 201. Where well depths make it necessary, the repeaters receive and re-transmit the data to the next station in the work string. This allows an integrated acoustic signal between DDBS 70 and WiSP 30(b). WiSP 30(b) transmits the signal to a Receiver/Transmitter 19, such as a Nautronics or Sonardyne commercial system, for relay to a vessel on the surface.
The following sequence of drawings shows the general steps required to utilize the communication plug in conjunction with the DDBS and wireless communication to provide a well control system with pressure barriers that can be verified from the surface of the sea.
The electronics will be able to transmit data for up to six months, deriving power from onboard batteries in each of the tools. Less frequent data bursts extend battery life; more frequent shorten battery life. This frequency of data bursts can be programmed into the downhole electronics before being run in the well.
When deployed in horizontal or highly deviated wells, operational sequences are similar to those described for vertical wells; however, the communication processes are normally different, since a combination of electromagnetic and acoustic relay devices will be required in a horizontal well, as shown in
Although the discussion of operations herein has been limited to the initial completion of a well, it should be understood that the apparatus and methods disclosed herein can to be applied to all intervention or abandonment operations in well, offshore or land. Intervention operations include all types of workovers of wells.
Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.
Claims
1. A dual downhole barrier assembly having a flow conduit therethrough for placement in a well, comprising:
- a first and a second barrier valve in the flow conduit;
- a first and a second packer to seal outside the flow conduit, the first packer being deeper than the second packer; and
- a pressure transducer and a wireless telemetry apparatus between the first and second packer for transmitting pressure data.
2. The assembly of claim 1 further comprising a ported sleeve disposed between the first and second barrier valve.
3. The assembly of claim 1 wherein the second packer is a retrievable packer and further comprising a polished bore receptacle below the second packer to allow removal of a portion of the conduit above the first packer.
4. The assembly of claim 1 further comprising a polished bore receptacle above the second packer.
5. The assembly of claim 1 wherein the first and second barrier valves are operable by a stinger prong.
6. The assembly of claim 2 wherein the ported sleeve is operable by a stinger prong.
7. A well suspension plug, comprising:
- a body having a sealing surface thereon adapted for setting in a well casing;
- a probe below the body containing an acoustic receiver; and
- a wireless telemetry pod in the body for communicating data collected below the body or on the body.
8. The plug of claim 7 further comprising a sensor on or below the body and below the sealing surface.
9. A method for verifying pressure barriers in a well, comprising:
- deploying the dual barrier assembly of claim 1 on a work string in a single trip into the well;
- manipulating the first and second barrier valves by movement of a stinger prong; and
- sending pressure data to a receiver where the data are communicated to test the first or the second packer of the dual barrier assembly.
10. The method of claim 9 wherein the receiver is disposed on a work string or running tool and the pressure data are communicated to surface.
11. The method of claim 9 wherein the work string further comprises a storage device and the pressure data are stored and later retrieved.
12. The method of claim 9 wherein the work string includes an on/off attachment and further comprising removing a top portion of the work string by operation of the on/off attachment and placing the suspension plug of claim 7 in the well and communicating the data to surface through the plug.
13. A method for placing verifiable pressure barriers in a well, comprising:
- deploying the dual barrier assembly of claim 1 on a work string and running tool in a single trip into a well; and
- removing at least a portion of the work string so as to deploy the suspension plug of claim 7 in the well.
14. The method of claim 13 further comprising providing transmitters and receivers to transmit pressure data from the plug to a ship.
Type: Application
Filed: Jan 25, 2013
Publication Date: May 30, 2013
Applicant: TEJAS RESEARCH AND ENGINEERING, LLC (The Woodlands, TX)
Inventor: Tejas Research and Engineering, LLC (The Woodlands, TX)
Application Number: 13/749,845
International Classification: E21B 47/06 (20060101);