In the oil and gas industry we rely heavily on cement evaluation logs to make a variety of decisions, many of which can potentially have a significant impact on our business. Improper interpretation of cement evaluation logs can cost the industry untold dollars due to things such as lost reserves, bypassed pay zones, lost production, ineffective stimulation treatments and unnecessary or ineffective remediation programs.
Cement bond logging has been around for more than 50 years, yet the technology for sonic tools has remained largely unchanged since the 1960s. In the early 1980s a new generation of cement evaluation tools came onto the scene that used an ultrasonic pulse-echo technique to determine the properties of the material behind casing. Additional enhancements have been made since that time but even the most advanced tools available today still leave some degree of uncertainty in determining whether or not cement has provided the required zonal isolation.
This presentation will attempt to provide an understanding of the challenges surrounding cement evaluation. It will cover the limits of current cement evaluation log technology and describe what information todayís tools can and cannot deliver. Information on how to improve the reliability of cement evaluation log interpretation and prevent making bad business decisions based upon that interpretation will be presented.
David Stiles has been a Senior Technical Advisor for ExxonMobil's Drilling Technical organization since 2004. In this role he provides technical support for ExxonMobil's worldwide drilling operations, specializing in well cementing and lost returns mitigation. He received a BS in Geology from Kansas State University in 1983. Prior to joining ExxonMobil, he accumulated more than 20 years of cementing, acidizing and hydraulic fracturing experience with two major service companies, working throughout North America, Europe, Africa and the Former Soviet Union. He is an active participant in API and ISO standards development, a past Chairman of API Subcommittee 10 on Well Cements and Chairman of API RP65. Throughout his career he has authored numerous professional publications and has been awarded patents for various well cementing methods.