Keep Your BHA Cooler While Drilling Through High-Temperature Formations

Abstract

Abstract Typically, drilling fluids exhibit lower rheological properties at elevated wellbore temperatures, which affect wellbore cleaning capabilities, filter cake stability, down-hole tools lifetime, and increase the possibility of stuck pipe events. Drilling through high temperature formations >300°F using oil-based drilling fluids often requires the use of mud coolers to help maintaining BHA tools and to reduce any risk of failures that can lead to high associated costs of non-productive time (NPT). To overcome the above associated challenges, field experience introduces a flexible engineered approach. This approach is based on a lubricant that is an environmentally acceptable and as polymeric fatty acid solution for oil-based muds (OBM). From an operational standpoint, this solution induces a cooling effect of the mud hundreds of feet ahead without the need of circulating it or using a mud cooler. This lubricant worked to reduce the frictional effect resulting in temperature reduction while drilling and maintaining uniform rheological property of the drilling fluids. Also, a laboratory work was conducted using a metal-to-metal approach to approve the lubricity effectiveness of this solution in friction reduction. An addition of 1-2% of the proposed lubricant to OBM system resulted in a drop in temperature by ~10°F. This paper aims to present the effect of drilling high-temperature wells >300°F which can lead to high potential of having failure in the measuring-while-drilling (MWD) system due to the equipment limitations. Furthermore, it shows how this lubricant solution could reduce circulation time to 50% per 1,000 feet and cool down MWD temperatures with torque reduction up to 6% compared to previous operations. Laboratory work also proved that this solution could provide friction reduction up to 23%. This friction reduction provides lower downhole temperature profiles by adding OBM lubricant while drilling and has significantly assist in minimizing NPT, the probability of MWD failures, and insure a smooth operation.