Successful Application of Multipurpose Thixotropic Technology for Lost Circulation, Wellbore Strengthening through Directional Tools in Well Control Events in Colombia
Authors: Toro Carlos , Velasquez Eliana , Avellaneda John , Olivella Luis Carlos , Luna Edgar 
Published: October 2023

Controlling lost circulation in formations that simultaneously present a narrow pore and fracture gradients window is one of the most complex situations to manage while drilling. High HSE risk generated by well control operational impacts profit by the non-productive days due to drilling equipment malfunction, quantity, and type of fluid loss, as well as potential directional tools lost in the hole when pipe should be cut down due to the impossibility of bringing the drill string to the surface and assure the well. All the risks could generate a not viable project.

At the present day, the greatest difficulty for controlling lost circulation through directional tools is the limited availability of technologies and limited loss circulation material (LCM) concentration range that could be pumped through the motor and the Measurement or Logging While Drilling (MWD/LWD) with the required concentrations to efficiently sealed the formation. This limitation is associated with the high risk of plugging the downhole tools, which would cause a more complicated operational situation such as the inability to manage loss and well-control situations with catastrophic HSE events.

Traditional lost circulation technologies are granular in nature and require large amounts of solids with a coarse size that exceeds the allowable pumped capability of the tools, or even technologies such as cement cannot be moved through these tools. In addition, these types of traditional pills are not part of an efficient solution when severe losses occur or for combined events with gas migration; the limited concentration and type of LCM not forming a solid, hard, compact, and impermeable structure that could penetrate the formation and develops compressibility greater than 500 psi helping to control gas migration from deeper formations.

The use of LCM technologies with high thixotropic rheological behavior fluids has become a good option based on a liquid phase with a very low solid size that has the property to transform from liquid to solid states depending on the operational requirements and temperature conditions. They have been able to be implemented in situations of loss of circulation control even with the use of directional tools. Another advantage is their setting and pumpable time adjusted according to specific situations, developing the desired thixotropy and reaching compressibility strength greater than 500 psi in really short time periods.

The present study shows the successful application of a high thixotropy loss control system in a well located in the Middle Magdalena Valley basin in Colombia. In this region exposed formations present high pore pressure and low fracture pressure that caused simultaneously mud losses and well control events while tripping out with motor and MWD/LWD tools. Limited pump capability does not allow the implementation of traditional circulation pills generating a high probability of losing the tools in the hole or even losing the entire well.

This document shows the first worldwide application of a high thixotropy pill technology through directional tools obtaining successful mud loss control, wellbore strengthening, and gas migration with positive results.