Mechanical Casing Exit Window Locator and Whipstock Alignment System

Abstract

A whipstock assembly for emplacing and orienting a whipstock within a wellbore. The whipstock assembly includes a whipstock, an anchor sub for securing the whipstock within the wellbore and a locating tool which is releasably secured to the whipstock. The locating tool includes a tool body with an inclined contact face and a hook which extends radially outwardly from the tool body. The hook is shaped and sized to engage a lower end of the casing exit window to align and orient the whipstock with the casing exit window.

What is claimed is: 
     
         1 . A whipstock assembly for orienting and aligning a whipstock with a casing exit window in a wellbore, the whipstock assembly comprising:
 a whipstock for diverting a drilling string through the casing exit window;   a locating tool which is releasably affixed to the whipstock, the locating tool having a tool body that is securable to a running string for running into the wellbore; and   a hook which extends radially outwardly from the tool body of the locating tool, the hook being shaped and sized to engage a lower end of the casing exit window.   
     
     
         2 . The whipstock assembly of  claim 1  further comprising:
 an anchor sub affixed to the whipstock, the anchor sub being moveable between an unset position, wherein the anchor sub and whipstock are not anchored within the wellbore, and a set position, wherein the anchor sub and whipstock are anchored within the wellbore. 
 
     
     
         3 . The whipstock assembly of  claim 1  wherein the hook is radially moveable inwardly and outwardly with respect to the tool body. 
     
     
         4 . The whipstock assembly of  claim 3  wherein the hook is biased radially outwardly by a resilient spring. 
     
     
         5 . The whipstock assembly of  claim 2  wherein the anchor sub comprises an inflatable packer device. 
     
     
         6 . The whipstock assembly of  claim 1  wherein the tool body of the locating tool presents an angled contact face which is shaped and sized to abut and contact an inclined landing surface of the whipstock in a complementary manner. 
     
     
         7 . A whipstock assembly for orienting and aligning a whipstock with a casing exit window in a wellbore, the whipstock assembly comprising:
 a whipstock having an inclined contact surface for diverting a drilling string through the casing exit window;   a locating tool which is releasably affixed to the whipstock, the locating tool having a tool body that is securable to a running string for running into the wellbore; and   a hook which extends radially outwardly from the tool body of the locating tool, the hook being shaped and sized to engage a lower end of the casing exit window.   
     
     
         8 . The whipstock assembly of  claim 7  further comprising:
 an anchor sub affixed to the whipstock, the anchor sub being moveable between an unset position, wherein the anchor sub and whipstock are not anchored within the wellbore, and a set position, wherein the anchor sub and whipstock are anchored within the wellbore. 
 
     
     
         9 . The whipstock assembly of  claim 7  wherein the hook is radially moveable inwardly and outwardly with respect to the tool body. 
     
     
         10 . The whipstock assembly of  claim 9  wherein the hook is biased radially outwardly by a resilient spring. 
     
     
         11 . The whipstock assembly of  claim 7  wherein the anchor sub comprises an inflatable packer device. 
     
     
         12 . The whipstock assembly of  claim 7  wherein the tool body of the locating tool presents an angled contact face which is shaped and sized to abut and contact the inclined landing surface of the whipstock in a complementary manner. 
     
     
         13 . A method of installing a whipstock within a wellbore having a main bore and a lateral bore which extends radially away from the main bore, the method comprising the steps of:
 disposing into the wellbore a whipstock assembly having a whipstock releasably secured to a locating tool, the locating tool having a tool body and a hook which extends radially outwardly from the tool body, the hook being shaped and sized to engage a lower end of a casing exit window;   engaging the lower end of the casing exit window with the hook; and   releasing the locating tool from the whipstock.   
     
     
         14 . The method of  claim 13  wherein the whipstock assembly further comprises an anchor sub affixed to the whipstock, the anchor sub being moveable between an unset position wherein the anchor sub is not anchored within the wellbore, and a set position, wherein the anchor sub is anchored within the wellbore; and
 further comprising the step of setting the anchor sub within the wellbore after the hook has engaged the lower end of the casing exit window. 
 
     
     
         15 . The method of  claim 13  wherein the step of engaging the lower end of the casing exit window with the hook aligns an inclined contact face of the whipstock with the lower end of the casing window.