Abstract: A high pressure poppet-type regulating valve for controlling fluids that have been pressurized up to approximately 20,000 psi (1,400 kg/cm.sup.2). In the preferred embodiment the disclosed gas-dampened valve includes a stainless steel tapered poppet which is slidably positioned within a bore of a stainless steel valve body having an integral tapered valve seat. A portion of the poppet has at least one tapered section having a preselected taper angle. The valve seat has a preselected taper as well. Preferably the tapered section of has a taper angle that is up to approximately 10% larger the taper angle of the valve seat to reduce erosion of the poppet and seat thereby allowing the poppet to be made of stainless steel in lieu of a more wear resistant material. The valve body of the preferred embodiment further includes opposed discharge ports for minimizing pressure imbalances thereby reducing cavitation-induced damage to the valve.

Abstract: Method of forming openings in structural substrates, especially oil and gas well casings, by providing a supply of a preselected liquid and providing a supply of preselected abrasive particles which are soluble in the liquid. The liquid and abrasive particles are combined to form an abrasive particle laden saturated solution having a predetermined concentration ratio exceeding the saturation point of the base liquid. The abrasive particle laden saturated solution is then pressurized to a predetermined delivery pressure and is routed to at least one jetting nozzle capable of expelling the abrasive particle laden saturated solution. The substrate, in which an opening is to be formed, is subjected to a directed expulsion of the abrasive particle laden saturated solution at a distance and for a period of time necessary to form an opening therethrough. Such abrasive particle laden saturated solution used and needed to form the opening is then considered to be residual.