Step Changes needed to Modernise T&D Software Colin Mason; Colin Mason BP Exploration Search for other works by this author on: This Site Google Scholar David C-K. Chen David C-K. Chen Halliburton Co. Search for other works by this author on: This Site Google Scholar Paper presented at the SPE/IADC Drilling Conference, Amsterdam, The Netherlands, February 2007. Paper Number: SPE-104609-MS https://doi.org/10.2118/104609-MS Published: February 20 2007 Connected Content Related to: Changes Needed To Modernize Torque-and-Drag Software Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Mason, Colin, and David C-K. Chen. "Step Changes needed to Modernise T&D Software." Paper presented at the SPE/IADC Drilling Conference, Amsterdam, The Netherlands, February 2007. doi: https://doi.org/10.2118/104609-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE/IADC Drilling Conference and Exhibition Search Advanced Search AbstractTorque and drag (T&D) modeling is regarded as an invaluable process to assist in well planning and to predict and prevent drilling problems. Although T&D software has existed for over 20 years, some confusion still exists over the validity of the models used to characterize drilling and completion operations. This paper provides an assessment of current limitations of the various T&D models (soft-string and stiffstring) and appraises their validity. Field data from various operations is used to illustrate certain limitations. The paper defines future requirements for what is considered to be the next generation of T&D models. Probably the most important technical requirement is a more realistic stiff-string model to correctly account for the impact of tubular stiffness, hole clearance and tortuosity effects.IntroductionThe basic mathematical model that underlies most T&D software has not changed significantly since its original inception1. By contrast, software user interfaces have improved dramatically as computer hardware, processor power and software functionality have evolved. Based on over two decades of industry access to drillstring simulation software, it is considered that the time is now right to reflect on the state of current models and identify future user requirements.This paper first examines some of fundamental issues associated with the core drillstring models. This is followed by specific discussions on coefficients of friction (friction factors), tubular buckling, wellbore tortuosity and fluid flow effects. A section is devoted to the practical limitations of T&D models and highlights common mistakes made by users. The paper concludes by defining some user requirements to satisfy needs of future drilling and completion communities for the next 20 years.Torque and Drag SoftwareT&D software is commonly used during planning to ensure that the proposed wellpath can be drilled and completed with available equipment. It is also used for rig sizing and drillstring optimization to ensure that well designs are feasible. At a more advanced level it is used to determine drilling limits for field development options. During planning, it is a common practice to build a degree of conservatism into the models to allow for the uncertainty that invariably exists. For challenging or complex wells, T&D software is often used in real-time mode. This is where T&D trend lines are predicted in advance and monitored during operations for adherence or deviation. The intent is to allow the drill site team to respond to any unexpected trend changes in a timely fashion. It is important to note that virtually all T&D software use steady state models. This means calculations are carried when the string is moving in a steady manner, i.e. no transient effects are incorporated.Soft-String ModelThe original soft -string T&D programs were based on a model developed by Exxon Production Research1,2. The softstring model is so called because it ignores any tubular stiffness effects; this means that the pipe is treated as a heavy cable, chain or rope lying along the wellbore. This means that axial tension and torque forces are supported by the string and contact forces are supported by the wellbore.This model assumes that the loads on the string result solely from the combined effects of gravity and frictional drag; a result of contact between the string and the wellbore. The frictional force is simply the product of the normal force acting between the string and wellbore and the coefficient of friction. The schematic in Figure 1 illustrates the forces acting on a single drillstring element. Keywords: drilling operation, friction factor, Artificial Intelligence, spe iadc 104609, Upstream Oil & Gas, information, requirement, limitation, static friction, torque Subjects: Drillstring Design, Drilling Operations, Torque and drag analysis This content is only available via PDF. 2007. SPE/IADC Drilling Conference You can access this article if you purchase or spend a download.
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Mason et al. (2007) studied this question.