Casing-heading phenomenon in gas-lifted well as a limit cycle of a 2D model with switches
| Authors: | Sinegre Laure, Ecole des Mines de Paris, France
Petit Nicolas, Ecole des Mines de Paris, France
Lemétayer Pierre, TOTAL, France
Gervaud Philippe, TOTAL, France
Ménégatti Philippe, TOTAL, France |
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| Topic: | 6.1 Chemical Process Control |
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| Session: | Control of Complex Processes |
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| Keywords: | Process Control, Dynamic Systems, Limit Cycles, Switching System, Gas-Lifted Well |
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Abstract
Oil well instabilities cause production losses. One of these instabilities, referred to as the "casing-heading" is an oscillatory phenomenon occurring on gas-lift artificially lifted well. This behavior is well represented by a 2D model with a vector field that is not continuously differentiable across several switching curves. These correspond to switches in flow rate functions describing the valves. Inorder to interpret the observed oscillations as a limit cycle we use the Poincaré-Bendixon theorem with a detailed study of uniqueness of trajectories and the derivation of a positive invariant set.
