The wire-line tubing perforator is an mechanically operated tool that is run onan ordinary steel measuring line into the tubing of a well, under pressure, todrive into a wall of the tubing, and securely lock in place, a tapered, cylindrical insert containing and orifice. Use of the perforator obviates thenecessity of pulling and rerunning the tubing to install jet collars or flowvalues, reduces the cost, and simplifies the task, of placing an oil well ongas-lift operation. More important, however, is the use of the tool with aremovable check value and stop, to provide a means of washing drilling mud fromthe annulus between the tubing and casing, and to complete the well for gaslift operation without exposing the producing formations to the mud column andwithout moving the tubing string.
This paper discusses the origin, development, and mechanics of the wire-lineperforator, the various purposes for which the tool was designed, and themethod of selecting orifice sizes for any depth, and gives the results obtainedthus far in practical application.
Several years ago, a tool that could be lowered on an ordinary steel measuringline into the tubing of a well under pressure was designed and constructed forthe purpose of punching a hole in the tubing walls above a shale bridge thathad completely plugged the tubing of a well under pressure was designed andconstructed for the purpose of punching a hole in the tubing of a well in theLong Lake field, East Texas. The well was in a low, swampy area, whichexcessive rainfall had caused to be inaccessible by car or truck for about fourmonths. The only equipment at the well site consisted of an ordinary steel wireline that had been carried there to measure the depth of the bridge. Since apulling unit could not be moved to the well site, and as the pressure on thecasing was 2100 lb. per sq. in., it became apparent that the only way out ofthe predicament was to make a perforating tool that could be lowered into thetubing on a measuring line and operated under pressure. Thus, the firstwire-line tubing perforator was designed and built as an expedient, and was notused extensively until it had been redesigned to meet more frequent andincreasingly urgent needs.
Until recently, it was necessary to pull the tubing to install jet collars orflow valves when a well was to be placed on gas lift. Because most companieseither maintained or had access to pulling units and crews for this work littleor no thought had been given to eliminating or even simplifying this task. Whenthe manpower and steel storage became so acute, however, many operatorssuddenly found themselves without facilities to equip their wells for gaslifting. The wire-line tubing perforator already had been tried and provedsuccessful, therefore operators immediately requested its use to punch gas-jetholes in the tubing, to eliminate the pulling and running of tubingstrings.
The first deficiency revealed by more general use of the perforator lay in theinability to regulate the size of the hold punched through the tubing.