Open hole straddle tool

A method for establishing fluid communication with an isolated zone of a wellbore comprising:

• providing a tool having a mandrel and a housing, the mandrel having a bore and being adapted at an uphole end for connection to a tubing string and being closed at a downhole end, and the housing carrying an uphole packer spaced axially along the housing from a downhole packer, the housing being movable axially on the mandrel between downhole and uphole positions;
• running in the tool, while at least periodically positioning the housing at a downhole position for establishing fluid flow from the wellbore below the downhole packer, through the bore of the mandrel and to the wellbore above the uphole packer while in the downhole position;
• positioning the housing at an intermediate position for blocking fluid flow between the bore of the mandrel and the wellbore above and below the packers, the housing being limited to movement between the downhole and intermediate positions by a movement limiting stop;
• applying a first pressure in the bore of the mandrel to actuate the uphole and downhole packers;
• applying a second higher pressure in the bore of the mandrel for releasing the limiting stop;
• positioning the housing at an uphole position for maintaining actuation of the packers, for continuing to block fluid flow between the wellbore above and below the packers and for opening fluid flow between the bore of the mandrel and the zone of the wellbore between the packers.

A tool for isolating a zone of a wellbore comprising:

• a mandrel having a bore and being adapted at an uphole end for connection to a tubing string and being closed at a downhole end;
• a housing carrying an uphole packer spaced axially along the housing from a downhole packer, the housing being movable axially on the mandrel between at least three positions;
• a first position for aligning cooperating bypass ports in the housing and the mandrel and thereby establishing fluid flow from the wellbore below the downhole packer, through the bore of the mandrel and to the wellbore above the uphole packer for running in the tool;
• a second position for
• misaligning the bypass ports and thereby blocking fluid flow between the bore of the mandrel and the wellbore above and below the packers and
• aligning packer release ports for establishing fluid communication with the uphole and downhole packers so that application of a first pressure in the bore of the mandrel actuates the uphole and downhole packers and isolates the zone therebetween;
• and
• a third position for
• misaligning the packer release ports for maintaining actuation of the packers
• misaligning the bypass ports, and
• aligning an operations port in the housing with an operation port in the mandrel for establishing fluid flow between the bore of the mandrel and the isolated zone.

A tool for isolating a zone of a wellbore comprising:

• a mandrel having a bore and being adapted at an uphole end for connection to a tubing string and closed at a downhole end;
• a housing carrying an uphole packer spaced axially along the housing from a downhole packer, the housing movable axially on the mandrel between a released position and a set position so that
• in the released position, uphole bypass ports in the mandrel and uphole bypass ports in the housing align and downhole bypass ports in the mandrel and downhole bypass ports in the housing align for fluid communication between the bore of the mandrel and the wellbore above and below the packers;
• and
• in the set position, the uphole and downhole bypass ports in the mandrel and the housing are offset for blocking fluid communication between the bore of the mandrel and application of a first pressure in the bore of the mandrel actuates the uphole and downhole packers.

A tool for isolating a zone of a wellbore comprising:

• a mandrel having a bore and being adapted at an uphole end for connection to a tubing string;
• a housing carrying an uphole packer spaced axially along the housing from a downhole packer, the housing movable axially on the mandrel between an uphole position, an intermediate position and a downhole position,
• means for flowing fluid between the wellbore below the downhole packer, the bore of the mandrel and the wellbore above the uphole packer while in the downhole position;
• means for isolating the bore of the mandrel from the wellbore in the intermediate position so that the packers are actuated when the fluid in the bore of the mandrel is actuated to a first pressure;
• means for blocking fluid between the wellbore below the downhole packer and the wellbore above the uphole packer while in the uphole position and establishing fluid communication between the bore and the isolated zone.