A Novel Experimental Setup for Testing Lost Circulation Material on a Large Scale for Geothermal Drilling Applications

Abstract

Lost circulation is a common and challenging problem encountered while drilling oil, gas, water, and geothermal wells. It costs the industry enormous resources, nonproductive time (NPT), and effort. In the United States, 10 to 20% of the geothermal well cost is spent on lost circulation treatments. Using lost circulation material (LCM) is the commonly used treatment method to prevent and cure lost circulation events. There are different types of LCMs and are generally classified into three main categories; granular, flakey, and fibrous materials. Selecting the appropriate material and optimizing the mud formulation is essential in designing the treatment method. Therefore, LCMs should be evaluated first in laboratories before field implementation. The LCM evaluation is always conducted using small-scale equipment in static or dynamic conditions such as plugging permeability apparatus. However, this small equipment does not fully represent the actual field conditions. It sometimes fails when the LCM particles block the tubes and valves opening, resulting in misleading findings and failure in field operations. This paper presents a novel experimental setup to evaluate lost circulation material in large-scale and high-temperature dynamic conditions (up to 350℉) to avoid the limitations of existing laboratory methods. The setup consists of a mud mixing and circulation system, heating system, pipe viscometer, main test section, and data acquisition system. In addition, several fractured discs were designed and 3D-printed using carbon fiber material to test the sealing efficiency of different LCMs. A detailed descrption of the experimental setup, 3D fractured discs, optimized operating procedure, and preliminary results are presented in this paper. The results showed promising findings and a novel testing procedure of different LCMs for geothermal drilling applications.