High-Resolution Wellbore Tortuosity Logs Improve Completion and Production Equipment Placement

Abstract

Wellbore tortuosity is a term that has steadily increased in relevance to the oil and gas industry over the past decade, but its importance is especially clear in the current environment. The convergence of several major global events - the ongoing COVID-19 pandemic and persistent weakness in commodity pricing - combined with the industry’s general attitude toward rate of penetration as the performance driver is leading to wells of inferior quality being drilled. The issue of wellbore quality is exacerbated by the division among drilling, completions, and production as functional disciplines, leading to dramatically different objectives and methods of quantifying success in each project phase. In wells with high tortuosity, the drilling process and drilling efficiency are affected, as well as the effectiveness of the completions and production equipment in achieving reservoir return rates. Defining wellbore tortuosity in relevant areas, such as openhole wellbores, production tubing, or casing, is often a very difficult task; historically, it has been a technical area fraught with challenges and misunderstandings. Though metrics designed to analyze wellbore tortuosity were developed in the past several decades, these generally relied on using the calculated dogleg of the wellbore every 95 ft. While such technologies were used with limited success, the received information lacked the precision and granularity necessary to explain the true difficulties of running and operating equipment in the well. Innovation was necessary. One such innovation is a system from Gyrodata that generates wellbore tortuosity logs in conjunction with a gyroscopic surveying tool or with another service that provides comparable data. The system defines reference lines for the wellbore path based on survey data and determines displacements of the wellbore path from the reference lines. Through a series of calculations based on this information, the wellbore shape can be represented and visualized in 3D, allowing an operator to make critical decisions on well development and placement for artificial lift and other equipment in line with areas of low tortuosity. By collecting high-resolution data at 1-ft intervals vs. the standard stand-length intervals of measurement-while-drilling (MWD) tools, the technology reveals areas of high sideloading forces and high friction that would otherwise be invisible. This allows improved rod-guide placement, reducing or eliminating casing (tubing) damage and necessary workovers. Also, the technology allows identification of areas of low tortuosity, thereby reducing premature failures, increasing equipment life, and mitigating cable damage while setting the electrical submersible pump (ESP).