High-Fluid-Loss, High-Strength Lost Circulation Treatments

Abstract

Abstract A new high-fluid-loss, high-strength (HFHS) pill system has been developed and optimized using innovative test methods and trialed to ensure that it meets field criteria for addressing lost circulation problems. This new HFHS pill system works over a wide range of loss rates and provides a more effective and stronger seal than traditional treatments. While the issue of lost circulation is one of the drilling industry’s most singular problems, the solutions are numerous and varied. Estimates of direct and associated costs to the lost circulation problem run into hundreds of millions of dollars globally, including whole mud losses, cost of treatment as well as lost time and tools. Discrete pills, formulated using a specific chemical and/or material blend, is one of the more popular approaches for curing severe lost circulation. These pills are mixed, pumped and spotted with the intention to either seal the loss zone or at least mitigate the losses sufficiently to regain the ability to circulate the wellbore fluid, control the well, and either continue drilling or set a string of casing. Using new and innovative laboratory test methods, this paper evaluates the effectiveness of several commercially available defluidizing lost circulation treatments and discusses the development of a new HFHS lost circulation system. This new treatment has been designed and optimized using unique methodology to meet a set of “ideal” criteria for use in the field. Specifically, it must be easy to deploy, carry a low operational risk, as well as being effective at curing losses.