Schlumberger

Single-Trip Sidetracking

Date: 05/30/2014

Accurately controlling kickoff depth and direction

Drillers deviate, or sidetrack, a wellbore for a variety of reasons. They sidetrack around obstacles or unstable formations or to change the bottomhole location. Often, engineers sidetrack as part of a plan to drill multilateral wells from a single vertical wellbore, thus exposing more of the reservoir to production.

The point of departure from the vertical hole is its kickoff point (KOP). If the KOP is in a cased hole, the driller must set a whipstock, mill a casing window, and then pick up a directional bottomhole assembly (BHA) to drill the sidetrack. The whipstock is oriented to establish the initial sidetrack direction. If the KOP is below casing depth, the driller often has to set a cement plug, then kick off from the plug using a directional drilling assembly to begin drilling the sidetrack. 

The success of the openhole sidetrack is dependent on the integrity of its cement plug. If the plug fails, the operator has to repeat the often costly and time-consuming process. To address this issue, engineers developed the TrackMaster OH openhole whipstock and sidetracking system. The system permits operators to lock a whipstock anchor in place and establish a reliable KOP at the precise depth and orientation required, often in a single trip. A cased hole version of the system is also available for more reliable and less time-consuming sidetracking operations.

An article in the Spring issue of Oilfield Review, “Whipstock Options for Sidetracking,” explains the development of these innovative whipstock solutions. Case studies from the US and the North Sea demonstrate the systems’ reliability and accuracy.

Read the full article at the Oilfield Review website.

Reference

Bruton, G., Land, J., Moran, D., Swadi, S., Strachan, R. and Tørge, K.: “Whipstock Options for Sidetracking,” Oilfield Review (Spring 2014) 26, No. 1 16–25.

Sidetracking After Pumping Cement

Single-trip Sidetracking

With its anchor in place, the TrackMaster OH-C system permits drillers to sidetrack without having to wait for cement to cure.