Attenuating Heave-Induced Pressure Oscillations using Automated Down-hole Choking

Kvernland, Martin; Christensen, M. Ø.; Borgen, Harald; Godhavn, John–Morten; Aamo, Ole Morten; Sangesland, Sigbjørn

doi:10.2118/189657-ms

Cited by 10 publications

(2 citation statements)

References 8 publications

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“…Therefore, there is almost no error between real heave velocity and the velocity estimated from acceleration measurements. In practice, small error between actual and estimated heave velocity will be a requirement on the hardware used, although first lab-scale experiments (see also Figure 5 in Kvernland, Christensen, Borgen, Godhavn, Aamo, Sangesland, et al (2018)) suggest that the heave velocity can be estimated relatively accurately in such a fashion and even better results should be expected with higher-quality hardware. Heave-estimator design tradeoffs taking into consideration the magnitude of noise and bias are also discussed in Godhaven (1998).…”

Section: Heave Velocity Estimationmentioning

confidence: 99%

Attenuating heave-induced pressure oscillations in offshore drilling by downhole flow control

Strecker

Aamo

2019

IFAC Journal of Systems and Control

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One of the challenges when applying managed pressure drilling (MPD) offshore on a floating rig is the wave-induced heaving motion of the rig. During drillstring extensions, the drillstring is rigidly attached to the rig and follows the rig's heaving motion. This induces pressure oscillations in the well that can violate pressure margins, in particular in rough conditions and when margins are tight. In order to enable drilling operations under such conditions, the pressure oscillations are to be attenuated by use of a controllable valve installed in the bottomhole assembly (BHA) at the bottom of the drillstring. The subject of this paper is the controller design for the valve flow based on measurements of the BHA movement and downhole pressure. Using a frequency-domain approach, the control law is designed to, in case of downwards BHA movement, reduce the valve flow to compensate the mud being displaced by the BHA and the flow due to mud clinging to the moving drillstring. Controlling the valve flow in such a manner creates large differential pressures over the valve that can potentially destabilize the BHA motion, which must be taken into consideration in the control design. Stability and performance of the closed-loop system are verified in simulations using a high-fidelity model of the drilling mud and elastic drillstring.

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Section: Heave Velocity Estimationmentioning

confidence: 99%

Attenuating heave-induced pressure oscillations in offshore drilling by downhole flow control

Strecker

Aamo

2019

IFAC Journal of Systems and Control

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“…Both approaches still use a top-side choke for pressure control, and neither solve issues that arise when drilling from floating installations; heaveinduced downhole pressure oscillations. b) Another approach is to use a downhole valve to reduce the pressure oscillations (Kvernland, 2018). c) For deep water, a reduced liquid level in the drilling riser (as opposed to increased backpressure topside) is used to control downhole pressure.…”

Section: Introductionmentioning

confidence: 99%

Drilling Library: A Modelica library for the simulation of well construction

Dadfar

Velut

Larsson

et al. 2019

Linköping Electronic Conference Proceedings

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A Modelica library for the simulation of well construction (drilling) is presented in this paper. The library contains most of the components of a drilling system. The simulation model is capable to capture the main dynamics of the well, including the hydraulics, the mud transport, the mechanics of the drill string as well as the drill bit interaction with the bore hole. The library is well suited to simulate the well operation and to support the development of new technologies. The modelling assumptions of the library's components are first reviewed. Subsequently, an experiment is performed to test the rotational and translational frictions.

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Automatic Control of Mud Pumps, Draw-Works and Top-Drive on a Floater

Daireaux

Erik

Cayeux

et al. 2019

SPE/IADC International Drilling Conference and Exhibition

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The application of safe-guards, safety triggers and automated procedures to control the mud-pumps, hoisting system and top-drive allows for safer, more consistent and more efficient drilling operations. Attempting to apply drilling automation on a floater needs to manage the impact of the unpredictable movement of the drill-string induced by heave movements. Because of the drill-string elasticity and the continuous movement of the rig, it is challenging to estimate the bit position, the bottom hole depth or the instantaneous rate of penetration. Yet, these estimations are crucial for the evaluation of cuttings production and their transport, or dynamic open hole pressures. Furthermore, the variability of the top of string movement can change abruptly when heave compensation is turned on or off or depending on the efficiency of the heave compensation system. These facts have an impact on the look-ahead strategy to determine safe drilling parameters. An existing drilling automation system, originally designed for fixed platforms, has been modified to meet those new requirements. For this first adaptation, only vertical drilling has been considered. Heave movements with and without compensation are constantly monitored so that sudden or slow changes in amplitudes get accounted for. Induced effects on downhole pressures are estimated via hydraulic simulations for a wide range of drilling and heave scenarios. Consequently, the design of the automation system had to be deeply modified to incorporate this additional dimension. The resulting system has been used for the drilling of three exploration wells, in eleven sections. Offshore drilling operations are characterized by a large variability of the drilling operation conditions. On a floater, the drilling context is even more challenging as it is subject to ever changing weather conditions. Yet, by utilizing model-based drilling automation solutions it is possible to improve drilling efficiency.

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Attenuating Heave-Induced Pressure Oscillations using Automated Down-hole Choking

Cited by 10 publications

References 8 publications

Attenuating heave-induced pressure oscillations in offshore drilling by downhole flow control

Attenuating heave-induced pressure oscillations in offshore drilling by downhole flow control

Drilling Library: A Modelica library for the simulation of well construction

Automatic Control of Mud Pumps, Draw-Works and Top-Drive on a Floater

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