DEBRIS CONTROL ARRANGEMENT FOR A WHIPSTOCK AND METHOD
A whipstock includes a whipstock body having a diverter face; and a swellable material disposed about the whipstock body and configured, positioned and dimensioned to interact with an inside dimension of a borehole in which the whipstock is run and method.
Latest BAKER HUGHES INCORPORATED Patents:
The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/941,810, filed Jun. 4, 2007, the entire contents of which are specifically incorporated herein by reference.
BACKGROUNDIn connection with the drilling of multilateral wellbores, whipstocks are often placed in a bore from which a lateral borehole is to be drilled. One of the problems associated with the use of whipstocks is that debris tends to collect around the circumference of the whipstock, in an annulus between the whipstock and the casing thereby rendering it difficult to retrieve the whipstock. Metal cuttings during the milling operation tend to collect in this annulus. The cuttings tend to become compacted in the annulus as well then upon an attempt to retrieve the whipstock uphole the cuttings can jam the same rendering it difficult or impossible to remove the whipstock. Moreover, it is not uncommon for formation cuttings or settling of solids in the mud fluid to settle around the circumference of the whipstock as well. Since, in many applications and particularly in Multilateral Wells, the whipstock is intended to be removed from the borehole after use, the collection of debris in the annulus and consequent difficulty or impossibility of removing the whipstock is undesirable. The art, therefore, will receive an arrangement capable of preventing or substantially alleviating the aforenoted problem.
SUMMARYA whipstock includes a whipstock body having a diverter face; and a swellable material disposed about the whipstock body and configured, positioned and dimensioned to interact with an inside dimension of a borehole in which the whipstock is run.
A method for preserving whipstock mobility includes applying a swellable material to a whipstock body; running the whipstock in a wellbore; and exposing the swellable material to a swelling fluid.
Referring now to the drawings wherein like elements are numbered alike in the several Figures:
Referring to
Applicant has discovered a way to effectively prevent the accumulation of debris in annulus 20 by adding a swellable material seal 22 in the form of a toroid around the largest circumference of the whipstock 14 and at a position on whipstock 14 immediately downhole of the whipstock diverter face 16. This position on the whipstock 14 guarantees that the seal 22 will be immediately adjacent to downhole edge 24 of window 12. This is advantageous, since in this position any debris dropping on the uphole end of the seal 22 will either fall into the lateral whereafter it will be circulated back to surface, or if it does not fall into the lateral, will be entrained with circulation fluid back to the surface in any event. This will prevent the buildup of debris and the consequent whipstock retrieval difficulties noted above.
The seal 22 comprises a swellable material because such material allows the seal 20 to itself have a smaller outside dimension during running and then to attain a larger outside dimension sufficient to seal against the wellbore 10 when the swellable material is exposed to a swelling fluid. The smaller initial outside dimension reduces damage to the seal during running up the whipstock to depth and further renders the running operation easier because it leaves a greater amount of open space between the whipstock end seal and the inside dimension of the wellbore 10. The swellable material may be of any type such the ultimate sealing is ensured. In one embodiment, the material is responsive to one or more of water, oil and methane and the reaction begins immediately upon the whipstock being introduced to the borehole. In other embodiment, the material is responsive to one or more of water, oil and methane at the reaction does not occur until later in the run of the whipstock. It may be that the swelling fluid is actually injected into the well or it may be that the fluid is an environmentally present fluid in the wellbore.
Referring to
Referring now to
Referring to
While preferred embodiments have been shown and described, 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 illustrations and not limitation.
Claims
1. A whipstock comprising: a swellable material disposed about the whipstock body and configured positioned and dimensioned to interact with an inside dimension of a borehole in which the whipstock is run.
- a whipstock body having a diverter face; and
2. The whipstock as claimed in claim 1 wherein the swellable material is toroidally shaped.
3. The whipstock as claimed in claim 1 wherein the swellable material is band shaped.
4. The whipstock as claimed in claim 1 wherein the swellable material covers the whipstock body exclusive of the diverter face.
5. The whipstock as claimed in claim 1 wherein the swellable material is responsive to at least one of water, oil and methane.
6. The whipstock as claimed in claim 1 wherein the swellable material is disposed parametrically about the diverter face.
7. A method for preserving whipstock mobility comprising:
- applying a swellable material to a whipstock body;
- running the whipstock in a wellbore; and
- exposing the swellable material to a swelling fluid.
8. The method for preserving whipstock mobility as claimed in claim 7 wherein the applying is toroidally.
9. The method for preserving whipstock mobility as claimed in claim 7 wherein the applying is in a band.
10. The method for preserving whipstock mobility as claimed in claim 7 wherein the applying is complete exclusive of a diverter face of the whipstock.
11. The method for preserving whipstock mobility as claimed in claim 7 wherein the applying is parametrically about a diverter face of the whipstock.
Type: Application
Filed: May 28, 2008
Publication Date: Dec 4, 2008
Applicant: BAKER HUGHES INCORPORATED (HOUSTON, TX)
Inventor: Alejandro Ortiz (The Woodlands, TX)
Application Number: 12/127,958
International Classification: E21B 7/08 (20060101);