Abstract: A stage valve with particular use in cementing a well bore annulus where the stage valve has pressure operated valve member for opening a flow passage in the stage valve and the valve member has differential pressure areas which maintain the valve member open while a fluid moves through the flow passage in one direction and which can be closed by fluid moving in an opposite direction. The flow passage has a choke to develop a pressure differential from the flow of fluid. Spring members can be used with the valve member to close the flow passage when the pressure differential of the fluid flow in one direction is insufficient to maintain the valve member in an open position.

Abstract: A system for inflating an inflatable packer located in a well bore on a liner where the inflatable packer has an inflation valve and a latching recess. An inflation tool with inner and outer assemblies is disposable by a string of tubing to a position within the inflatable packer where cup members on the outer assembly straddle the inflation valve and friction drag block members on the outer assembly are located in an annular recess above the inflation valve.

Abstract: A stage valve with particular use in cementing a well bore annulus above an inflatable packer located in a well bore on a liner where the stage valve has pressure operated outer sleeve members for opening a flow port in the stage valve and an inner sleeve member actuated by the trailing plug behind a liquid cement slurry to close the flow port whereupon spring members act on at least one of the outer sleeve members to close off the flow port on the exterior of the stage valve.

Abstract: A process for determining suitable parameters of temperature and/or pressure to use in a cementing operation in a wellbore to obtain a positive seal of cement in an annulus between a liner and a borehole wall after the cement has set up and where the process utilizes the parameters of differential temperature in a well bore, pressure on the cement to obtain a positive borehole wall stress (and positive seal) in a cementing operation.

Abstract: A method for determining a proper inflation pressure for an elongated inflatable packer to effect a positive contact stress seal of an elastomer packer element with a borehole wall in a wellbore traversing earth formations. The temperature differential for each layer in a radial plane is determined. The final contact stress, the finite inflation pressure required to inflate the packer element and the temperature differential are functionally interrelated to one another to obtain a final contact stress or the packer element with a borehole wall.