The Value of High-Definition Wellbore Surveys in an Arctic Land Environment

Abstract

Abstract Since 1929, when the first wellbore surveying tool was developed, drillers and geologists have looked on in anticipation as the industry worked persistently at improving the technology. Today, the majority of work is limited to accelerometers, magnetometers, and gyroscopic tools. Surveying in the Arctic is particularly challenging since magnetometers have an inherent error in the physics of the measurement that make them less favorable at high latitudes. Gyroscopic tools are not particularly suited to the drilling environment and are usually run after the drilling process, losing their real-time advantages. Accurate well placement is vital to the success of hydrocarbon production; accurate surveys are required in real time to drill complex 3D wells that penetrate multiple small geological targets and avoid costly risks of drilling out of the production zone. Meanwhile, interest in the Arctic region is growing, in part because of possibilities for resource development, new access to transportation routes, and climate change. Energy companies are certain to be at the forefront of Arctic development and investment. In the Arctic environment, with the error terms already inflated, an improvement in positional certainty can be a welcomed change. Technology that enables taking surveys continuously with downhole tools while drilling and reprocessing the data in real time give us the opportunity to eliminate errors associated with surveying frequency such as true vertical depth (TVD) error or inaccurate tortuosity. TVD assurance utilizing the high-definition survey technology has been used with several new approaches, for example, to reduce rig time on surveys by increasing the interval between stationary surveys without degradation in positional certainty. This technology also helps in understanding real borehole tortuosity and thus has an influence on drilling optimization and well completion strategy, helping the drilling engineers to create better models, for example, by improving modeling torque and drag. This paper will discuss the drivers for high-definition surveying in Russian Arctic land drilling, the science of the measurements, and the technology behind this unique method for survey calculations. Case histories will also be discussed in detail before, finally, making some conclusions about the future of this method as it relates to increasing positional certainty.