Dynamic Simulations Provide Development Drilling Improvements
Authors: Frenzel M. 
Published: October 2008

Ultimately, it's all about drilling performance. The successful development of offshore reservoirs requires drilling programs that are both effective and efficient in safely reaching the target intervals. Profitability and economic constraints dictate how fields are developed, and they influence to what extent technology can be used to improve the overall drilling program. Both service companies' field engineers and operators' drilling engineers all too often see the negative impact of ineffective drilling practices and processes that result in unacceptably short runs, damaged drill bits and broken tools/components.

Engineering discipline teaches us to learn from these negative experiences, utilizing the data provided by the complex drilling and logging systems available to us today to better understand what might have caused the problems. While our common goals of accomplishing as many drilling objectives as possible, concurrent with a contingency plan to minimize the possibility of a premature failure, in many cases little is done during a wellâ??s planning phase, to identify and quantify the dynamic processes that can be detrimental to system performance, or more importantly, to improve performance.

Each operator and its respective vendor support teams have their own "tool kits" and consulting/resident experts to help manage and utilize offset well data in pursuit of these goals. However, these efforts are typically limited to static or steady state analyses designed to understand only a specific part of the total system or just the component level behavior at one moment in time. In many cases, these studies are analogous to obituaries of sorts, which do little more than describe how and when the patient died. These post-well methodologies are supported by their software/diagnostic analyses that are applied to gain insight into the process forces downhole that may have resulted in having to pull out of the hole (POOH) due to operational problems or tool failure.. If only there were a better diagnostic tool that would have allowed the experts to see the patient and address the underlying problems before it was too late. An ounce of prevention in these cases can be worth many thousdands, or even millions, of dollars in savings!

While each of these consulting teams and experts provide valuable insights into the system's condition at the moment of the failure, they are somewhat constrained in their scope of investigation. Their investigative and analytical capabilites often lack the degree of sophistication necessary to include the more complex down-hole tools involved in the incident. Moreover, without the ability to model the entire system and fully understand the interaction of the combined components with each another in a dynamic sense, their investigation may identify only a part of the problem, leaving behind "unlearned lessons" to be repeated on subsequent wells or buried forever in the cement of the sidetracked wellbore.

Without a method to understand the dynamic behavior of a complete drilling system as a function of time the hidden clues that may hold the answer to improved performance may be missed only to create similar problems in a subsequent wells, or at best achieving only incremental improvements well-to-well.