Abstract: This invention relates to a method and apparatus for perforating the formation in a wellbore wherein the wellbore is established for the production of hydrocarbons. The formation is perforated by explosive material carried in pistons which are carried within either the pipe casing or the collars or both and remain generally within the maximum outward profile of the pipe string so as not to interfere with the movement and placement of the pipe string in the wellbore. The pipe string may be rotated, reciprocated and circulated which enhances the ability of the installer to place the pipe string in a deviated or long reach wellbore. Once the pipe string is in place, the pistons may be deployed by one of several methods such that pistons mounted in openings in the peripheral wall of the pipe string move outwardly with sufficient force to move the pipe string way from the walls of the wellbore sufficient to form a complete annulus for cementing.

Abstract: A pressure monitoring apparatus for use in a tubing string having a landing nipple located therein above a well zone which is to be monitored includes a plug body, a mandrel sleeve, a pressure communication mandrel and a pressure sensor. The plug body is landed in the landing nipple, and has an axial body bore therethrough. The mandrel sleeve has a lower portion constructed to be sealingly received within the body bore, and has an axial sleeve bore disposed therethrough. The pressure communication mandrel has a lower portion constructed to be sealingly received within the sleeve bore, and has a pressure communication passage disposed therethrough for communicating the pressure sensor with the well zone. The pressure monitoring apparatus can be adapted for use in methods of monitoring pressure fall-off in a subsurface formation after injection of fluid into the formation, and also can be adapted for use in methods of monitoring a bottom hole shut-in pressure buildup in a production well.

Abstract: Saline source water containing dissolved oxygen is deoxygenated to form injection quality water in the disclosed process and apparatus. In accordance with the invention, saline source water is electrolyzed in an electrolytic cell which produces hydrogen and chlorine. The hydrogen is reacted with the dissolved oxygen in a catalyst resin bed to reduce the dissolved oxygen to the desired level. Optionally, evolved chlorine may be used as a biocide in the system.

Abstract: A sidestream of injection liquid taken downstream of a filter is passed through a monitoring filter of appropriate pore size. Pressure drop over the monitoring filter is determined and a regeneration cycle for the main filter is triggered in response to differential pressure (.DELTA.P) over a preset value, which corresponds to deterioration in filtrate quality.