Review and analysis of historical leakages from storage salt caverns wells

Twelve incidents involving well casing and/or cement leaks in the salt caverns storage industry are described. These incidents occurred at the following storage sites: Eminence salt dome, Mississippi; Elk City, Oklahoma; Conway, Kansas; Yoder, Kansas; Mont Belvieu, Texas; Teutschenthal/Bad Lauchstädt, Germany; Clute, Texas; Mineola, Texas; Hutchinson, Kansas; Magnolia, Louisiana; Boling, Texas; Epe, Germany. Mechanisms leading to a casing leak and consequences are discussed. In most cases, a breach in a steel casing occurred at a depth where a single casing was isolating the stored product from the geological formations. The origin of the breach was due in most cases to poor welding/screwing conditions and corrosion, or excessive deformation of the rock formation. In this, the age of the well is often influential. In many cases, the leak path does not open directly at ground level; fugitive hydrocarbons first escape and accumulate in the subsurface prior to migrating through shallower horizons and escaping at ground surface. A pressure differential between hydrocarbons in the borehole and fluids in the rock mass favours fast leak rates. A wellhead pressure drop often is observed, even when the stored product is natural gas. The incidents described suggest that thorough monitoring (tightness tests) and a correct well design would lessen considerably the probability of a casing leak occurring

Review and analysis of historical leakages from storage salt caverns wells

Twelve incidents involving well casing and/or cement leaks in the salt caverns storage industry are described. These incidents occurred at the following storage sites: Eminence salt dome, Mississippi; Elk City, Oklahoma; Conway, Kansas; Yoder, Kansas; Mont Belvieu, Texas; Teutschenthal/Bad Lauchstädt, Germany; Clute, Texas; Mineola, Texas; Hutchinson, Kansas; Magnolia, Louisiana; Boling, Texas; Epe, Germany. Mechanisms leading to a casing leak and consequences are discussed. In most cases, a breach in a steel casing occurred at a depth where a single casing was isolating the stored product from the geological formations. The origin of the breach was due in most cases to poor welding/screwing conditions and corrosion, or excessive deformation of the rock formation. In this, the age of the well is often influential. In many cases, the leak path does not open directly at ground level; fugitive hydrocarbons first escape and accumulate in the subsurface prior to migrating through shallower horizons and escaping at ground surface. A pressure differential between hydrocarbons in the borehole and fluids in the rock mass favours fast leak rates. A wellhead pressure drop often is observed, even when the stored product is natural gas. The incidents described suggest that thorough monitoring (tightness tests) and a correct well design would lessen considerably the probability of a casing leak occurring

Une mesure de la perméabilité et du fluage d'une caverne dans le sel

Rock mass properties diff er significanùy from those measured on sam pies in the laboratory. A test has been performed on a deep brine-fi.lled ca vern, with the objective of measuring the equilibrium pressure reached when the ca vern was closed. Such an equilibrium is reached when salt mass creep, which leads to cavern shrinkage, balances brine permeation through the ca vern wall. A K = 2·10-19 m 2 value of the average in situ intrinsic permeability has been deduced from the test; it is significantly higher than the intrinsic permeability measured in a weil or in the laboratory. This result supports ca vern abandonment scenarios in which the risk of natural fracturation due to high brine pressures is alleviated.Les propriétés d'un massif rocheux sont en général différentes de celles mesurées au laboratoire sur un échantillon. On a cherché la pression d'équilibre à laquelle se stabilise la saumure contenue dans une cavité souterraine profonde fermée. Cet équilibre résulte de l'action du fluage du massif, qui tend à refermer la cavité, et de la perméation de la saumure à travers les parois de la cavité. On déduit de la valeur d'équilibre mesurée une perméabilité intrinsèque moyenne de l'ordre de $K = 2·10^{-19}\text{m}^2$, sensiblement plus forte que les valeurs estimées antérieurement sur des échantillons ou dans un puits. Ce résultat permet de construire un scénario du comportement de la caverne après abandon, qui exclut le risque de fracturation naturelle

Editorial

International audienceNo abstract availabl