The check valve positioned within a production tubing string is configured to open when a differential pressure across the check valve exceeds a specified opening differential pressure. With the check valve closed, a specified volume of gas is flowed from the production tubing string, thereby decreasing the pressure within the production tubing string from a first wellhead pressure to a second, lesser wellhead pressure. Hydrostatic pressure within the production tubing string at the check valve is increased by flowing a specified volume of water into the production tubing string above the check valve to at least partially replace the specified volume of gas. After flowing the water, a specified volume of treatment fluid is injected into the production tubing string at an injection pressure less than the first wellhead pressure and greater than the second wellhead pressure, thereby opening the check valve and flowing the treatment fluid downhole.

The check valve positioned within a production tubing string is configured to open when a differential pressure across the check valve exceeds a specified opening differential pressure. With the check valve closed, a specified volume of gas is flowed from the production tubing string, thereby decreasing the pressure within the production tubing string from a first wellhead pressure to a second, lesser wellhead pressure. Hydrostatic pressure within the production tubing string at the check valve is increased by flowing a specified volume of water into the production tubing string above the check valve to at least partially replace the specified volume of gas. After flowing the water, a specified volume of treatment fluid is injected into the production tubing string at an injection pressure less than the first wellhead pressure and greater than the second wellhead pressure, thereby opening the check valve and flowing the treatment fluid downhole.

The present invention discloses a permanent packer and an extended gas lift method using the permanent packer, the method comprising: S1. imbedding the extended gas lift embedded pipe when setting the permanent packer, wherein the extended gas lift embedded pipe has an upper end being closed and a lower end being open, is provided therein with a one-way valve through which the fluid can pass from top to bottom; S2. lowering a breaking device from the production casing when in the extended gas lift, to break the upper end of the extended gas lift embedded pipe such that the upper and lower ends of the extended gas lift embedded pipe are communicated; and S3. injecting gas into the production casing, lifting the accumulated liquid in the bottom hole to the ground surface, to complete the extended gas lift. The method does not affect the sealing property of the permanent packer, can fully adapt to the demand in the early and middle stages of gas well development, and meanwhile can realize extended gas lift without workover in the middle and later stages of gas well development, and has low implementation cost and good safety.

The present invention relates to a downhole expandable metal tubular having an axial extension, to be expanded in a well downhole to abut against an inner face of a casing or a borehole, comprising a first section having a first outer diameter, two circumferential projections having a second outer diameter which is larger than the first outer diameter, a second section arranged between the two projections, each projection having an inclined face tapering from the second outer diameter towards the second section, wherein the second section has a third outer diameter which is smaller than the first outer diameter in an unexpanded condition, and a sealing element is arranged between the projections opposite the second section, so that during expansion the second section bulges more radially outwards than the first section, forcing the sealing element radially outwards. Furthermore, the present invention relates to an annular barrier, a downhole completion and a sealing expansion method.

Provided is an apparatus, as well as a method for establishing a seal between a mandrel and a borehole. The apparatus, in one aspect, includes a mandrel, and a packer, the packer including: a constrained portion coupled to the mandrel; and an unconstrained portion made of a swellable material and coupled to the constrained portion, wherein the unconstrained portion is free to move with respect to the mandrel. The apparatus, according to one aspect, further includes a spring positioned between the mandrel and the unconstrained portion and configured to urge the unconstrained portion away from the mandrel, the spring having a spring force less than a yield strength of the swellable material when the swellable material is in an unswelled condition.

A method and apparatus to move an object in an open hole section of a wellbore. A bottom hole assembly including a downhole pulling tool and fishing device is described. The downhole pulling tool includes an open hole anchor to allow location of the downhole pulling tool in the open hole section of the wellbore so as to reduce the operating distance between the downhole pulling tool and the fishing device. An embodiment in which a cut section of tubular is removed from the open hole section is described. A casing cutter may also be located in the bottom hole assembly to cut the tubular on the same trip in the well as removing the cut section of tubular.

A method and apparatus to move an object in an open hole section of a wellbore. A bottom hole assembly including a downhole pulling tool and fishing device is described. The downhole pulling tool includes an open hole anchor to allow location of the downhole pulling tool in the open hole section of the wellbore so as to reduce the operating distance between the downhole pulling tool and the fishing device. An embodiment in which a cut section of tubular is removed from the open hole section is described. A casing cutter may also be located in the bottom hole assembly to cut the tubular on the same trip in the well as removing the cut section of tubular.

An inflatable down hole bag includes an inflatable body for holding an inflation fluid and a container for holding one or more substances. The container is disposed inside of the inflatable body and includes a closure for keeping the one or more substances in the container when the closure is in an inoperative state. The closure also releases the one or more substances from the container when the closure is in an operative state. Release of a substance causes an inflation fluid producing reaction within the inflatable body, thereby inflating the inflatable body. The container includes at least two separated chambers. Each chamber holds a respective one of the substances. The closure includes a stopper for closing a respective opening to one of the chambers. The closure further includes an actuator for removing each stopper from the respective opening so as to release each substance from each respective chamber.

An inflatable down hole bag includes an inflatable body for holding an inflation fluid and a container for holding one or more substances. The container is disposed inside of the inflatable body and includes a closure for keeping the one or more substances in the container when the closure is in an inoperative state. The closure also releases the one or more substances from the container when the closure is in an operative state. Release of a substance causes an inflation fluid producing reaction within the inflatable body, thereby inflating the inflatable body. The container includes at least two separated chambers. Each chamber holds a respective one of the substances. The closure includes a stopper for closing a respective opening to one of the chambers. The closure further includes an actuator for removing each stopper from the respective opening so as to release each substance from each respective chamber.

A swellable packer assembly that includes a mandrel, a sealing element disposed about a least a portion of the mandrel, and a degradable metal coating disposed about at least a portion of an outer surface of the sealing element. The degradable metal coating fluidly isolates the portion of an outer surface of the sealing element from an exterior of the coating and the sealing element is formed of a material responsive to exposure to a fluid in a wellbore to radially expand from the mandrel. The degradable metal coating is selectively removable from the mandrel downhole so as to expose the sealing element to the fluid in the wellbore.