When you take a look at the oil industry these days, what is the one thing you hear and read about the most? “Shale plays.” Operators are developing resources, purchasing acreage, and purchasing companies that have acreage in the USA and in countries around the world, now more than ever before.
For long-term economic stability of these projects, they need to be drilled as inexpensively and as fast as possible–basically, they need to be “factory-type wells.” The main fluid-related challenges associated with shale drilling are rate of penetration (ROP), shale stability, torque and drag, and waste management. Many of these wells are being drilled with nonaqueous fluids (NAFs) to meet these challenges, with the only real issue being waste management. However, there are technologies being used that reduce the amount of waste generated with NAFs, such as premium solids-control systems and thermal-desorption methods.
In an effort to eliminate NAF waste-management issues, drilling-fluids companies have developed fit-for-purpose water-based drilling fluids for each of the major shale plays. The shale regions around the world vary in depth, mineralogy, temperature, and other characteristics, and a single fluid formulation does not fit all circumstances. Each fluid is customized to the unique characteristics of a particular shale region. Fluids companies have specific products and chemistries that are designed for a specific type of shale and drilling operation.
As technological advances enable exploitation of shale resources around the world, the challenge will be to find the most-cost-effective solution. As always, the lowest overall well cost may not result from the lowest-cost-per-barrel drilling fluid. One has to take into account ROP, torque and drag, wellbore stability, and waste management when determining the most-cost-effective solution.
There were many good papers written this year, and I have tried to choose a variety of universal topics. Please take time to read them and the papers listed as additional reading.
Read the paper synopses in the November 2011 issue of JPT.
Brent Estes, SPE, is a Drilling Fluids Specialist for Chevron Energy Technology Company supporting worldwide drilling operations. Previously, he was with ExxonMobil and Baroid Drilling Fluids. Estes earned a BS degree in petroleum engineering from Texas A&M University. He has a broad background in all aspects of drilling and completion fluids, including fluids research and development and working as a drilling engineer. Estes has authored several SPE papers and serves on the JPT Editorial Committee.