Open Hole Whipstock Technology Combines Cement Abandonment and Kick-Off in Single Trip

Abstract

In every basin around the world, planned or contingency open hole sidetrack operations are commonplace in drilling operations. In the recent year, there has been an evolution of the open hole whipstock systems to reduce sidetrack time/cost associated with kicking off from cement plugs. The most recent advancement for these systems combines kick-off operations in the same trip as setting whipstock and cementing the open hole below.

The whipstock systems that came to market in the recent unconventional shale era provided the industry a much-needed low risk/efficient option in wells where cement abandonment was required or desired, but kick-off from the whipstock was completed on the following trip. The most recent advancement in open hole whipstock technology utilizes the same concave, anchors, and abandonment methods but is deployed on a cutting structure rather than a running tool. The added ability to kick off in the same trip now further reduces sidetrack times when compared to cement plug or conventional whipstock kick-off operations.

This new open hole system has been installed in 18 wells in the United States (US), three different hole sizes, with 10 of these applications including cement operations to abandon and isolate the open hole below the whipstock. The original version of this technology was run on a crushed/insert carbide milling bottomhole assembly (BHA). The most recent cutting structure has been changed to polycrystalline diamond compact (PDC) cutters to decrease average kick-off times by around 50% and reduce the risk of a second trip in hard/abrasive formations. Two recent installs, including cement abandonment and PDC technology, highlight the success and benefits of this system. The first install was required because a radioactive source was left in the hole and the required deflection device (whipstock) could be used to sidetrack/continue well construction while pumping the required red cement and kicking off efficiently in one trip. Total well possession time for the operation including the wellbore preparation run was 64.5 hours. The second install was a planned pilot hole application with the kick-off being in the hard/abrasive shale. The local regulatory agency required the cement abandonment of lower exposed zones. Total well possession time for the operation including two wellbore preparation runs was 102 hours.

This paper shows that advancements in open hole whipstocks provide the industry with a reliable/efficient option for planned or contingency sidetracks. This sidetracking solution can be used in various applications worldwide to lower total time spent on the well construction process.