Background of the Invention: Field of the Invention The invention is related to the field of oil well drilling and re-entry. More particularly, the invention is related to providing an arrangement to facilitate the re- entry of lateral boreholes by coil tubing in a consistent, economical and reliable manner.

Prior Art A Bowen Lebus knuckle joint or similar has traditionally been employed to provide the impetus for coil tubing to reenter lateral boreholes. Bowen Lebus knuckle joints deflect under hydraulic pressure, the deflection being translated to the coil tubing and urging the coil tubing against the inner wall of the primary casing. Providing the coil tubing is properly oriented, the end thereof will scrape along the primary casing until it finds the lateral window and then will slip into and through the lateral window and into the lateral borehole. Providing the proper orientation of the coil tubing can be provided by some type of directional orienting tool run prior to the coil tubing (i. e., on an earlier workstring) or a simple trial and error technique. Employing the trial and error technique is, of course, functional since eventually the coil tubing will enter the lateral, however, it is not particularly efficient.

U. S. Patent No. 5,373,906 to Braddick discloses an anchor or guide assembly connected with a work string and may include a drill string. The guide assembly includes an internal tubular member to releasably connect with the working string. A tube is within the internal tubular member. The internal tubular member is releasably secured with an outer tubular member. The internal tubular member is releasably secured with an anchor surface. The work string is released from the internal tubular member to move relative to the guide assembly to extend the tube from the internal tubular member for performing various operations. An orienting setting enables operations to be performed at various angles and directions from a location and, in this event, the outer tubular member includes a heel window and a face window and the internal tubular member has articulations to bend the internal tubular member or tube therein laterally to direct the tube laterally of a location when the work string is lowered. Braddick requires a significant number of cooperating devices, thus subjecting it to a high possibly of failure.

Summary of the Invention: The above-discussed and other drawbacks and deficiencies of the prior art are overcome or alleviated by the coil tubing re-entry device of the invention.

The present invention comprises an entry guide hung from coil tubing which entry guide includes an orientation anchor for rotating the guide assembly such that a diverter surface inside the housing of the guide assembly is appropriately angled to "kick off the coil tubing into the desired lateral. A guide lug and slot construction are employed to orient the guide assembly. Once the guide assembly is properly oriented with the original whipstock packer the coil tubing is simply moved downhole which forces it into the lateral of choice. It should be noted that the bottom hole assembly (BHA) may be, and is preferably, run on the end of the coil tubing inside the housing of the guide assembly such that the entire operation desired may be accomplished in one trip downhole. Upon completion of the operation in the lateral, the coil tubing is withdrawn uphole until its end is within the guide assembly and then the guide

assembly may be withdrawn from the borehole along with the coil tubing. This is facilitated by features on the end of the coil tubing which cannot pass through the top sub. Provision is made, of course, for emergency release of the coil tubing from the housing by shearing particular shear pins in the top sub. Upon shearing the pins the safety release sleeve 34 and the BHA may be drawn uphole leaving the rest of the top sub, housing and bottom sub of the guide assembly for pickup with a conventional fishing tool.

The arrangement of the invention alleviates all of the difficulty the prior art experiences with respect to multiple runs downhole and efficiency with respect to time required to complete the entry to the lateral.

The above-discussed and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description and drawings.

Brief Description of the Drawings : Referring now to the drawings wherein like elements are numbered alike in the several FIGURES: FIGURE 1 is a quarter sectioned elevation view of the guide assembly of the invention; FIGURE 2 is an elevation view of the invention wherein the premachined window is visible; FIGURE 3 is a quarter sectioned elevation view of the top sub of the invention.

Description of the Preferred Embodiment: Referring to FIGURE 1, housing 10 is quartered-sectioned to illustrate diverter plate 12 extending from the downhole edge of premachined window 14 and to illustrate the carrying assembly (mandrel) 16 of coil tubing 17 which prevents the removal of coil tubing through the top sub 18 of the guide assembly 20. At the downhole end of the device of the invention, an orientation sub is endowed with an orientation lug slot 24

which is well illustrated in FIGURE 2. Orientation sub 22 is also visible in FIGURE 1, but illustrates only half of orientation lug slot 24.

In operation, guide assembly 20 is run downhole at the end of coil tubing 17.

Upon reaching the original whipstock packer, upon which the original whipstock rested to drill the lateral borehole, the guide assembly 20 is oriented by orientation lug slot 24 to turn guide assembly 20 until window 14 is coextensive with the lateral borehole.

Guide assembly 20 is freely rotatable on coil tubing 17 and no special movement of the assembly is required to provide the orientation necessary. Upon orientation resulting in a coextensive position of window 14 and the lateral borehole, the plate 12 is angled toward the borehole to facilitate the entry of the coil tubing thereinto. The invention very simply and effectively expedites re-entry into the lateral with coil tubing.

Another benefit of the invention is that there is no special action required to facilitate coil tubing 17 moving into the preexisting lateral since tubing weight must merely be slacked off downhole until the end of the coil tubing impacts and kicks off of diverter 12.

Because of the method of operation of the invention, particularly the one trip operation thereof, it may be possible to contain the entire BHA within the housing of the guide assembly for run in and draw out or the carrying assembly 16 may be installed at an appropriate place in the BHA. Moreover, it is advantageous to ensure that the guide housing 20 is of the proper length to position diverter plate 12 at the proper height to kick the coil tubing off into the lateral. This is easily adjustable since the system is completely modular and the guide is made with conventional wash pipe connections on top and bottom rendering the addition of extra pipe length an easy affair. An additional benefit of this arrangement is that a bit or mill on the bottom hole assembly may be completely maintained within the guide assembly providing protection to the bottom hole assembly during tripping, if desired. Wash pipe connections are illustrated at 26 and 28 illustrated in FIGURE 1.

Subsequent to completing the operation in the lateral borehole for which the bottom hole assembly was tripped, the coil tubing 17 need merely be withdrawn uphole

through top sub 18 until the carrying sub has returned to its running position within housing 10 of assembly 20. Upon obtaining this position, coil tubing 17 can no longer be removed uphole since feature 16 prevents the coil tubing from being removed from the top sub 18 of guide assembly 20. Further withdrawal of coil tubing uphole will disengage assembly 20 from the original whipstock packer and remove the assembly uphole.

Referring to FIGURE 3, the top sub 18 of the invention is illustrated in a quarter section which renders visible a shear pin 32 in a safety release sleeve 34. As can be seen, mandrel 36 cannot pass through the top section of top sub 18 because of the safety release sleeve 34, however in the event that guide assembly 20 becomes stuck in the original whipstock packer the shear pin 32 and safety release sleeve 34 enable the operator to retrieve the coil tubing and the bottom hole assembly without significant difficulty. Upon discovering that assembly 20 is jammed downhole, the operator must merely increase tension on the coil tubing to an amount sufficient to shear the shear pin 32 allowing the safety release sleeve 34 to travel uphole with the mandrel and bottom hole assembly while leaving the rest of top sub 18, housing 10 and orientation sub 22 of guide assembly 20 in the downhole position. Thereafter, the remaining housing of guide assembly 20 may be removed from the downhole position with a fishing tool such as a Bowen series 150 overshot tool or a spear tool such as Baker Oil Tools type "D"spear Part No. 120-09. It should be understood that guide assembly 20 of the invention may be of any length required to completely envelop the bottom hole assembly and is frequently thirty feet in length. The length adjustability is achieved by using spacer subs which easily attach within the guide assembly by washpipe connections on top and bottom thereof.

While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustration and not limitation.

What is claimed is: