Advanced Automatic Control for Dual-Gradient Drilling

Abstract

Managed pressure drilling offers unprecedented capabilities for precise pressure control in drilling operations. This capability, created by the availability of new hardware tools, creates the need for tight coordination of such tools, to ensure reliable and safe operation. The use of model predictive control is proposed as a multivariable control framework that can coordinate multiple variables to offer both better performance and higher reliability and safety compared to current practice. A case study on a dual-gradient drilling system is presented to demonstrate how model predictive control can simultaneously control bottomhole pressure and hook position during drill string movement, by simultaneously manipulating the main pump flow rate, seabed pump flow rate, and drill string velocity. Computer simulations show that the proposed approach results in much lower bottomhole pressure deviations during drill string movement that manual control of hook position alone. The implications of this study as well as future directions for integration of additional variables and use of appropriate model predictive control variants are discussed.

Feedback control of proppant bank heights during hydraulic fracturing for enhanced productivity in shale formations

“…We want to note that over the last 10 years, the oil and gas production industry has applied model predictive control (MPC)-based algorithm to drilling processes to enhance pressure control flexibility and process safety. [48][49][50][51][52][53][54][55][56][57][58][59] However, its application to hydraulic fracturing has not received much attention because of (a) limited availability of real-time measurements, (b) presence of uncertainties in the measurement data, and (c) large computational requirements due to the dynamic simulation of highly coupled PDEs defined over a time-dependent spatial domain.…”

Drilling Automation: Presenting a Framework for Automated Operations

“…Nonlinear models increase the complexity of the calculations. Detailed description of supervisory control levels in drilling (MPD) operations are described in detail in Breyholtz et al (2009). The main objectives of an MPC controller are in prioritized order as follows (Qin and Badgewell 2003): 1.…”

“…If there are more MVs available than CVs, ideal resting values for the excessive MVs can be introduced. In Breyholtz et al (2009), such a system is demonstrated with an ideal resting value for the circulation rate. It is important to note that the ideal resting values will be obtained only as long as the first and second priorities are accomplished.…”

Automatic control of managed pressure drilling

“…The nonlinear MPC model employed is described in detail in Breyholtz et al (2009c). The nonlinear solver in the MPC controller is a single-shooting multi-step quasiNewton method (Meum et al, 2008).…”