| 摘要 |
METHOD AND APPARATUS FOR PERFORATING FORMATIONS IN RESPONSE TO TUBING PRESSURE The present invention presents a method and apparatus for perforating a well in response to fluid pressure in a first tubing string while establishing a pressure balance in response to pressure in a second string, or in the well casing, through which the well will be produced. Additionally, redundant firing heads may be provided for perforating guns utilized to assure optimal reliability of the system. One or more perforating equipment assemblies may be employed in a tool string, each of which includes redundant firing mechanisms responsive to pressure in the tool string. Additionally, a firing head assembly is utilized which is initially responsive to pressure in the tool string, but which is subsequently actuated by annulus pressure. The firing head is suitable for use with much lower annulus pressures than are utilized with conventional hydraulically actuated firing head assemblies. |
