Wells – Wells with lateral conduits
Reexamination Certificate
2002-06-12
2003-11-18
Schoeppel, Roger (Department: 3672)
Wells
Wells with lateral conduits
C166S117600, C166S242600, C175S061000, C175S062000
Reexamination Certificate
active
06648069
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to apparatus and methods for conducting well operations at a-particular depth and angular orientation within a borehole and more particularly, to apparatus and methods for permanently marking a depth and angular orientation within the borehole, and still more particularly to a reference number set at a particular depth and orientation in the borehole for conducting a well operation such as a sidetracking operation in a single trip into the well.
2. Description of the Related Art
Well operations are conducted at a known location within the well bore. This location may be relative to a formation, to a previously drilled well bore, or to a previously conducted well operation. For example, it is important to know the depth of a previous well operation. However, measurements from the surface are imprecise. Although it is typical to count the sections of pipe in the pipe string as they are run into the borehole to determine the depth of a well tool mounted on the end of the pipe string, the length of the pipe string may vary due to stretch under its own weight and will also vary with downhole temperatures. This variance is magnified when the pipe string is increased in length, such as several thousand feet. It is not uncommon for the well tool to be off several feet when depth is measured from the surface.
In completions it is known to use a no-go ring in the casing string to set a depth location in a well. A typical no-go ring is a thin shouldered device disposed within the casing string which has an inside diameter approximating the drift diameter of the casing string. No-go rings are used to engage and stop the passage of a well tool being run through the well bore. The annular shoulder of a no-go ring is approximately {fraction (1/16)}
th
of an inch thick on each side so that it will engage the well tool. Other well tools with a smaller diameter are allowed to pass through the no-go ring.
Many well operations require locating a particular depth and azimuth in the borehole for well operations. One such well operation is the drilling of one or more lateral boreholes. One typical sidetracking operation for drilling a lateral wellbore from a new or existing wellbore includes running a packer or anchor into the wellbore on wireline or on coiled tubing and then setting the packer or anchor within the wellbore. The packer or anchor is set at a known depth in the well by determining the length of the wireline or coiled tubing run into the wellbore. A second run or trip is made into the wellbore to determine the orientation of the packer or anchor. Once this orientation is known, a latch and whipstock are properly oriented and run into the wellbore during a third trip wherein the latch and whipstock are seated on the packer or anchor. One or more mills are then run into the wellbore on a drill string to mill a window in the casing of the wellbore. The whipstock is then retrieved. Subsequent trips into the wellbore may then be made to drill the lateral borehole to install a deflector or other equipment for down hole operations.
Further, in conventional sidetracking operations, although the depth of the packer or anchor used to support the whipstock is known, the orientation of the packer or anchor within the wellbore is not known. Thus, a subsequent trip must be made into the wellbore to determine the orientation of the packer or anchor using an orientation tool. The packer or anchor has a receptacle with an upwardly facing orienting surface which engages and orients the orientation tool stabbed into the packer or anchor. The orientation tool then determines the orientation of the packer or anchor within the wellbore. Once the orientation of the packer or anchor has been established, the orientation of the latch, whipstock and mill to be subsequently disposed in the wellbore is then adjusted at the surface so as to be properly oriented when run into the wellbore. The latch, whipstock and mill are then run into the wellbore and stabbed and latched into the packer or anchor such that the face of the whipstock is properly directed for milling the window and drilling the lateral borehole.
Since the packer or anchor are not oriented prior to their being set, the receptacle having the orienting surface and a mating connector may have an orientation that could lead to the receptacle being damaged during future operations. If the receptacle is damaged too badly, then it will not be possible thereafter to use it for orientation and latching of a subsequent well operation.
It is preferred to avoid numerous trips into the wellbore for the sidetracking operation. A one trip milling system is disclosed in U.S. Pat. Nos. 5,771,972 and 5,894,889. See also, U.S. Pat. No. 4,397,355.
In a sidetracking operation, the packer or anchor serves as a downhole well tool which anchors the whipstock within the cased borehole against the compression, tension, and torque caused by the milling of the window and the drilling of the lateral borehole. The packer and anchor have slips and cones which expand outward to bite into the cased borehole wall to anchor the whipstock. A packer also includes packing elements which are compressed during the setting operation to expand outwardly into engagement with the casing thereby sealing the annulus between the packer and the casing. The packer is used for zone isolation so as to isolate the production below the packer from the lateral borehole.
An anchor without a packing element is typically used where the formation in the primary wellbore and the formation in the lateral wellbore have substantially the same pressure and thus the productions can be commingled since there is no zone pressure differentiation because the lower zone has substantially the same formation pressure as that being drilled for the lateral. In the following description, it should be appreciated that a packer includes the anchoring functions of an anchor.
The packer may be a retrievable packer or a permanent big bore packer. A retrievable packer is retrievable and closes off the wellbore while a permanent big bore packer has an inner mandrel forming a flowbore through the packer allowing access to that portion of the wellbore below the packer. The mandrel of the big bore packer also serves as a seal bore for sealing engagement with a another well tool, such as a whipstock, bridge plug, production tubing, or liner hanger. The retrievable packer includes its own setting mechanism and is more robust than a permanent big bore packer because its components may be sized to include the entire wellbore since the retrievable anchor and packer does not have a bore through it and need not be a thin walled member.
One apparatus and method for determining and setting the proper orientation and depth in a wellbore is described in U.S. Pat. No. 5,871,046. A whipstock anchor is run with the casing string to the desired depth as the well is drilled and the casing string is cemented into the new wellbore. A tool string is run into the wellbore to determine the orientation of the whipstock anchor. A whipstock stinger is oriented and disposed on the whipstock at the surface, and then the assembly is lowered and secured to the whipstock anchor. The whipstock stinger has an orienting lug which engages an orienting groove on the whipstock anchor. The whipstock stinger is thereby oriented on the whipstock anchor to cause the face of the whipstock to be positioned in the desired direction for drilling. The whipstock stinger may be in two parts allowing the upper part to be rotated for orientation in the wellbore. The method and apparatus of U.S. Pat. No. 5,871,046 is limited to new wells and cannot be used in existing wells since the whipstock anchor must be run in with the casing and cannot be inserted into an existing wellbore.
U.S. Pat. No. 5,467,819 describes an apparatus and method which includes securing an anchor in a cased wellbore. The anchor may include a big bore packer. The wall of a big bore packer is roughly the same as th
Campbell John E.
Dewey Charles H.
Xu Wei
Conley & Rose, P.C.
Schoeppel Roger
Smith International Inc.
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