in the closed position the pad valve restricts flow through the annulus here the pad valve has contact between the shoulder 52 and the moveable joint 54 forming a seal to block fluid flow through the annulus at the pad valve referring to fig7 a through 7d there is shown a production tubing assembly 110 according to the present invention the production tubing assembly 110 is mated in a conventional manner and will only be briefly described herein assembly 110 includes production pipe 140 that extends to the surface and a production screen assembly 112 with pac valve assembly 108 controlling fluid flow through the screen assembly in a preferred embodiment production screen assembly 112 is mounted on the exterior of pac valve assembly 108 pac valve assembly 108 is interconnected with production tubing 140 at the uphole end by threaded connection 138 and seal 136 similarly on the downhole end 169 pac valve assembly 108 is interconnected with production tubing extension 113 by threaded connection 122 and seal 124 in the views shown the production tubing assembly 110 is disposed in well casing 111 and has inner tubing 114 with an internal bore 115 extending through the inner bore 146 of the assembly the production tubing assembly 110 illustrates a single preferred embodiment of the invention however it is contemplated that the pac valve assembly according to the present invention may have uses other than at a production zone and may be mated in combination with a wide variety of elements as understood by a person skilled in the art further while only a single isolation valve assembly is shown it is contemplated that a.