Automation of Drawworks and Topdrive Management to Minimize Swab/Surge and Poor-Downhole-Condition Effects

Abstract

Unwary axial and rotational movement of the drill-string can cause formation fracturing or fluid influx resulting in costly remedial actions. With increasingly complex wellbore geometries and narrow geo-pressure windows, it is not always obvious for the Driller to estimate the real manoeuvring limits of the drawworks and the topdrive, especially under poor downhole conditions. The solution presented in this paper uses continuously updated safe guards applied to the drilling control system to maintain a downhole pressure within the acceptable limits of the open hole formations. It also stops automatically the movement of the drill-string in case of abnormal hook loads or surface torques. Since automatic actions can be triggered in case of an unexpected situation, some standard procedures have been fully automated, including friction tests and backreaming.Numerical models are used to constantly calculate the maximum accelerations and velocities which can be applied to the drill-string in the current drilling conditions. The resulting envelope of protection is depending on many factors. Therefore, a proper evaluation of the downhole conditions is of paramount importance for the quality of the calculated safe guards. An automatic calibration of the physical models, based on surface measurements, is at the heart of the system. The calibrated mechanical models are used to determine the limits for abnormal surface torques or hook loads. It is therefore possible to automatically take actions in case of overpull, set-down weight or high torque.In 2008, a preliminary version of the system has been tested during the drilling of a well in the North Sea. Even though the control algorithms did work well at that time, it has been noticed that in some circumstances the drilling control system would not be ready in time for fast changing drilling conditions. An improved version of the drawworks and topdrive automation system has been tested during the drilling of three North Sea wells in the spring of 2009. In this last version, the response time of the system has been optimal at all time. The Drillers involved in the testing of the system have found the system useful and user-friendly.

Autonomous Decision-Making While Drilling

“…The drilling automation system continuously calculates maximum and minimum values for hook load, torque, and pump pressure, accounting for changing drilling conditions such as bit depth, temperatures, and cutting concentrations in the wellbore. In our case, the implemented approach for calculation of maximum and minimum values is model-based, using the observer-based approach described in [4]. The drilling control system is continuously updated with the maximum and minimum values for hook load, torque, and pump pressure.…”

“…Some of the first ideas for applying automation to the drilling process date to 2004 [2]. It became clear that executing automated procedures could not be done without several protection mechanisms such as safe operating envelopes (SOE) and fault detection and mitigation (FDM) [3,4]. The application of standardized procedures under the protection of SOE and FDM functions have shown that automated drilling operations were both possible [5] and increased the efficiency [6].…”

Drilling Systems Automation: Current State, Initiatives and Potential Impact

“…While surface instrumentation has lagged in development, automation quality sensors are available (Florence and Iversen 2010;Ronaes et al 2012). Software models are being developed and tested that provide monitoring and prediction capability in real-time, as the well is drilled (Dashevskiy et al 2003;Rommetveit et al 2004;Iversen et al 2006;Cayeux and Daireaux 2009;Cayeux et al 2011;Wong et al 2013;among others). Software models address the entire automation spectrum.…”

From machine control to drilling control

“…• Drill by wire: Such a system is an enhancement of the Drilling Control System to account for the side effects of the drill-string and drilling fluid movements on the drilling process [5] [6]. It implements safe guards to maneuver the drilling machineries in a way which reduces the risk for causing drilling incidents like formation fluid influx, hole collapse, formation fracturing, cuttings accumulation.…”