Abstract: A well barrier can include an inner mandrel, a flow passage, and a releasably secured plug. The plug blocks fluid flow through the flow passage, and includes a shoulder that prevents the plug from displacing completely through the inner mandrel. A method of treating a subterranean well can include treating a deeper zone, setting a well barrier in the well between the deeper zone and a shallower zone, then treating the shallower zone, and then applying a pressure differential from the deeper to the shallower zone, thereby displacing a plug out of the well barrier. A well treatment system can include a well barrier with a plug releasably secured to an inner mandrel. The plug is released by application of a pressure differential in a longitudinal direction, and fluid communication is unblocked by application of a pressure differential in an opposite longitudinal direction.

Abstract: A running tool sets and cements a liner in a borehole. While the tool's bypass section is closed, a plug deployed to the tool diverts hydraulic pressure to set a liner hanger in the borehole. The setting plug is unseated, and the bypass section is switched opened by deploying another plug to an opening seat and shifting a control sleeve open relative to a bypass port. While the tool's packoff remains sealed in the hanger, cement pumped out the bypass port is bullheaded into a lap of the liner and borehole. When cementing is complete, the bypass section is switched closed by deploying another plug to a closing seat and shifting the control sleeve closed relative to the bypass port. The bypass section is then placed in a flow-through condition where fluid communication is reestablished through the tool to the liner by allowing fluid to flow past the plugs in the tool.

Abstract: A running tool sets and cements a liner in a borehole. While the tool’s bypass section is closed, a plug deployed to the tool diverts hydraulic pressure to set a liner hanger in the borehole. The setting plug is unseated, and the bypass section is switched opened by deploying another plug to an opening seat and shifting a control sleeve open relative to a bypass port. While the tool’s packoff remains sealed in the hanger, cement pumped out the bypass port is bullheaded into a lap of the liner and borehole. When cementing is complete, the bypass section is switched closed by deploying another plug to a closing seat and shifting the control sleeve closed relative to the bypass port. The bypass section is then placed in a flow-through condition where fluid communication is reestablished through the tool to the liner by allowing fluid to flow past the plugs in the tool.

Abstract: A wiper plug is used in an operation to cement tubing in a borehole. The wiper plug is pumped down the tubing to separate an advancing fluid from a following fluid of the cementing operation, and an internal pressure chamber is maintained in a throughbore of the wiper plug between uphole and downhole barriers. The wiper plug eventually lands in the tubing, and the uphole barrier is removed by applying a first predetermined pressure against the uphole barrier. Removal of the uphole barrier is facilitated by the known and controlled internal pressure of the plug's chamber. The downhole barrier is also removed so that flow is permitted through the throughbore of the wiper plug. To perform a tubing pressure test, the downhole barrier can be removed due to pressure, and the chamber may have a temporary valve to hold applied pressure to a test level. Alternatively, the downhole barrier can hold the applied pressure. The temporary valve and the downhole barrier can then be self-removing in response to a stimulus.

Abstract: A well barrier can include an inner mandrel, a flow passage, and a releasably secured plug. The plug blocks fluid flow through the flow passage, and includes a shoulder that prevents the plug from displacing completely through the inner mandrel. A method of treating a subterranean well can include treating a deeper zone, setting a well barrier in the well between the deeper zone and a shallower zone, then treating the shallower zone, and then applying a pressure differential from the deeper to the shallower zone, thereby displacing a plug out of the well barrier. A well treatment system can include a well barrier with a plug releasably secured to an inner mandrel. The plug is released by application of a pressure differential in a longitudinal direction, and fluid communication is unblocked by application of a pressure differential in an opposite longitudinal direction.

Abstract: A well barrier can include an inner mandrel, a flow passage, and a releasably secured plug. The plug blocks fluid flow through the flow passage, and includes a shoulder that prevents the plug from displacing completely through the inner mandrel. A method of treating a subterranean well can include treating a deeper zone, setting a well barrier in the well between the deeper zone and a shallower zone, then treating the shallower zone, and then applying a pressure differential from the deeper to the shallower zone, thereby displacing a plug out of the well barrier. A well treatment system can include a well barrier with a plug releasably secured to an inner mandrel. The plug is released by application of a pressure differential in a longitudinal direction, and fluid communication is unblocked by application of a pressure differential in an opposite longitudinal direction.

Abstract: A well barrier can include an inner mandrel, a flow passage, and a releasably secured plug. The plug blocks fluid flow through the flow passage, and includes a shoulder that prevents the plug from displacing completely through the inner mandrel. A method of treating a subterranean well can include treating a deeper zone, setting a well barrier in the well between the deeper zone and a shallower zone, then treating the shallower zone, and then applying a pressure differential from the deeper to the shallower zone, thereby displacing a plug out of the well barrier. A well treatment system can include a well barrier with a plug releasably secured to an inner mandrel. The plug is released by application of a pressure differential in a longitudinal direction, and fluid communication is unblocked by application of a pressure differential in an opposite longitudinal direction.