Field Tests Indicate New Perforating Devices Improve Efficiency in Casing Completion Operations
- R.T. Wade (Schlumberger Well Surveying Corp.) | E.M. Pohoriles (Schlumberger Well Surveying Corp.) | W.T. Bell (Schlumberger Well Surveying Corp.)
- Document ID
- Society of Petroleum Engineers
- Journal of Petroleum Technology
- Publication Date
- October 1962
- Document Type
- Journal Paper
- 1,069 - 1,073
- 1962. Original copyright American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Copyright has expired.
- 2.4.3 Sand/Solids Control, 5.5.2 Core Analysis, 4.1.2 Separation and Treating, 3.2.3 Hydraulic Fracturing Design, Implementation and Optimisation, 2.2.2 Perforating, 5.6.4 Drillstem/Well Testing, 1.6.9 Coring, Fishing
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New completion concepts by the petroleum industry have resulted in renewed activity in the design of perforating equipment. This paper covers (1) the development and use of explosive devices for the "single-point entry" technique used in formation preparation, (2) field results achieved with the reactive-liner shaped-charge ("Crack-Jet") perforators and (3) a discussion of the magnetic positioning of perforating guns. Through application of magnetic positioning devices, uniform high-performance perforations may be made in large casings with small, through-tubing guns. Field results have indicated an appreciable advantage in the placement of a circular notch or several perforations in the plane of desired fracture initiation. The use of radial-firing, multi jet devices for the "single-point entry" technique is discussed. Reactive-liner shaped charges, initially field-tested in West Texas, have been used in all types of formations, both consolidated and unconsolidated. Field results are presented, and various formation test targets perforated with the reactive-liner charge are shown. Performance in several problem areas indicates improved rates of injection and more-favorable production rates.
Rapid changes in completion practices during the past few years have required the development of new perforating tools. The need for small, through-tubing perforators to penetrate large casings has led to the technique of magnetic positioning. The advantages of the "single-point entry" technique for formation fracturing have been realized by the development of radial-firing explosive devices for use on electrical cables. A major breakthrough in shaped-charge design has been achieved with the new reactive liner which develops high lateral pressures within the perforation, resulting in cleaner holes and, in tight formations, intensive fracturing. These recent developments provide increased efficiency and permit successful revision of older completion techniques.
Through-tubing completions, which continue to gain in popularity, pose additional problems in gun design. Besides improved safety and convenience, they make possible a differential pressure into the wellbore at the time of shooting which results in cleaner perforations. The trend in recent years has been toward even smaller-size tubings to permit multiple completions. Gun design problems, already severe in the small diameters, thus have increased. Excessive ranges of clearance that are encountered create a major problem in the design of through-tubing perforators. Clearance is defined as the distance from the perforator to the casing along the axis of the jet. Fig. 1 illustrates the clearance problem resulting from the use of a 1-11/16-in. gun below 2-in. tubing. In 7-in. casing the individual shot clearances could vary from 0 to 4 1/2-in. Obviously, the performance on the large-clearance shots would be drastically reduced; both penetration and entrance hole sizes are severely affected.
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