Technology Focus: Drilling and Completion Fluids (November 2009)

Abstract

Technology Focus The success or failure of a well is a function of many factors. One important influence is the drilling fluid. As companies deal with drilling more-complex and -difficult wells, a well-designed drilling fluid can contribute to the success of the well. The year's highlights range from laboratory studies on fluid/chemical effects that relate to borehole stability to complex-fluid physical properties that mitigate lost returns. With ever-increasingly complex wells being drilled, the role of a drilling-fluid engineer has changed as well. When I started in the fluids industry 15 years ago, we were concerned mostly about controlling fluid loss, plastic viscosity, yield point, and gels. To meet today's challenging wells, we have to be educated about the aforementioned fundamental properties as well as borehole stability, narrow-margin drilling, and lost returns, in addition to environmental regulations and waste management. A good example is in the lost-returns arena. With the increasing understanding of rock mechanics, a more systematic approach to lost-returns remediation was developed. Only a few years ago, most people were unfamiliar with concepts such as "building stress or integrity" and terms such as "hoop stress," "stress cage," and "fracture-closure stress." No longer are the days of pumping "everything but the kitchen sink" down the hole in an often futile attempt to stop losses! Now, we take a science-based approach to fluids and engineer the particle sizes to stop lost returns and reach drilling objectives in less time and at a lower cost. The roles of fluids specialists working for operators and fluids companies are changing as well. They have become knowledgeable about more than just fluid makeup and properties. Companies have engineers and scientists on staff who research issues such as borehole stability, lost returns, waste management, and environmental regulations around the world. Please take time to read the following summaries as well as the suggested additional reading. Drilling and Completion Fluids additional reading available at OnePetro: www.onepetro.org SPE 120646 • "Quest for a Pragmatic Drilling-Fluid-Performance Index—Key to Improving Fluid Performance and Optimizing Quality-Well-Delivery Economics" by Peter Osode, SPE, Petroleum Development Oman, et al. SPE 123013 • "Changing Shale Strengths With Invert-Emulsion Drilling Fluids: Theory, Measurement, and Modeling" by T. Hemphill, Halliburton, et al. SPE 119269 • "Drilling-Fluid Design Prevents Lost Returns by Building Integrity Continuously While Drilling in East Texas" by Kenneth B. Vaczi, SPE, ExxonMobil, et al.