Abstract: A downhole system for multistage fracturing wherein a stopper assembly is installed in a plugging device in manner that allows pressure integrity from above the plugging device, and the stopper assembly is further configured to allow a bore of the plugging device to open with an at least minimal pressure from therebelow in order to remove a stopper from a baffle in order to open a flow path through the plugging device in either direction.

Abstract: A plugging device for use in multistage fracturing a subterranean formation. The plugging device includes a plug body having a distal end, a proximate end, and an outer surface. There are a plurality of grooves disposed on the outer surface, and an index sleeve movingly disposed on the outer surface, the index sleeve configured to engage the plurality of grooves. The index is incrementable with respect to the plurality of grooves from the distal end toward the proximate end.

Abstract: A downhole system for multistage fracturing having a first cluster of valves, and a second cluster of valves downhole from the first cluster. Each of the first and second cluster of valves has a frac valve. At least one of the first and the second cluster of valves has a flex valve. A single plugging device is used to open all of the valves in the second cluster, but leaves all valves in the first cluster closed.

Abstract: A downhole system for multistage fracturing wherein a stopper assembly is installed in a plugging device in manner that allows pressure integrity from above the plugging device, and the stopper assembly is further configured to allow a bore of the plugging device to open with an at least minimal pressure from therebelow in order to remove a stopper from a baffle in order to open a flow path through the plugging device in either direction.

Abstract: A downhole tool suitable for use in a wellbore, the tool having a cone, a first sleeve, and a lower sleeve. The downhole tool includes the first sleeve, or a portion thereof, disposed around one end of the cone. After activation, the lower sleeve is engaged with the first sleeve, leaving a remnant cone-sleeve component configured to plug a restriction.

Abstract: A system for stimulating a subterranean formation that has a wellbore formed within the subterranean formation; and a tubular disposed within the wellbore. There is a first frac valve disposed within the tubular, the first frac valve having a first sleeve in a closed position, and further configured to move to an open position. There is an at least a second frac valve disposed within the tubular, the second frac valve having a respective sleeve in a respective closed position, and further configured to move to a respective open position. A dart is configured to pass through the first frac valve without moving the first sleeve, and to subsequently engage the second frac valve to move the respective sleeve to the respective open position.

Abstract: A downhole system for multistage fracturing having a first cluster of valves, and a second cluster of valves downhole from the first cluster. Each of the first and second cluster of valves has a frac valve. At least one of the first and the second cluster of valves has a flex valve. A single plugging device is used to open all of the valves in the second cluster, but leaves all valves in the first cluster closed.

Abstract: A system for stimulating a subterranean formation that has a wellbore formed within the subterranean formation; and a tubular disposed within the wellbore. There is a first frac valve disposed within the tubular, the first frac valve having a first sleeve in a closed position, and further configured to move to an open position. There is an at least a second frac valve disposed within the tubular, the second frac valve having a respective sleeve in a respective closed position, and further configured to move to a respective open position. A dart is configured to pass through the first frac valve without moving the first sleeve, and to subsequently engage the second frac valve to move the respective sleeve to the respective open position.

Abstract: A system is provided, run on a liner, for stimulating one or more stages of a downhole wellbore. The system includes one or more frac valves arranged on the liner; each of the frac valves presenting an identical inside profile, the frac valves being openable for providing fluid communication between in inside of the liner to outside of the wellbore; and at least one dart deployable into the liner, and being adjustable to pass through one or more frac valves without opening said one or more frac valves, and to engage and open one or more other frac valves. Each of the at least one darts is identical to another. A method is further provided for stimulating one or more stages of a downhole wellbore.

Abstract: A system is provided, run on a liner, for stimulating one or more stages of a downhole wellbore. The system includes one or more frac valves arranged on the liner; each of the frac valves presenting an identical inside profile, the frac valves being openable for providing fluid communication between in inside of the liner to outside of the wellbore; and at least one dart deployable into the liner, and being adjustable to pass through one or more frac valves without opening said one or more frac valves, and to engage and open one or more other frac valves. Each of the at least one darts is identical to another. A method is further provided for stimulating one or more stages of a downhole wellbore.