Slim-Hole Tubing Was One Key to the Successful Production of Natural Gas from a Production of Natural Gas from a Low-Permeability, Low-Porosity Reservoir

This paper was prepared for the Rocky Mountain Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in Billings, Mont., May 15–16, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.


The successful application of high-pressure hydraulic fracturing using glass beads as the proppant resulted in a commercial completion in proppant resulted in a commercial completion in the Hall sand of the Cotton Valley formation in the Lisbon Field, Caliborne Parish, La. The Burgess Simmons sand was also added as development drilling progressed across the structure. The initial production rates were relatively lo (500 to 600 Mcf/D) and it was found that the vertical gas velocity in 2-7/8-in. OD tubing was not sufficient to keep a well unloaded, resulting in a very rapid drop in production. The completion program was revised to use 2-7/8-in. OD tubing as a "frac" string and a 1-1/4-in. tubing was used as the completion string in both single and dual wells. This field would have been of questionable economic value if a successful revised completion had not been developed.

The production history of the low PI wells indicated that fluid buildup was also occurring in some of the 1 1/4-in. tubing strings as the formation pressure dropped. The wells were produced with various reduced tubing pressures produced with various reduced tubing pressures in a test program, prepared to evaluate flow efficiencies, production declines, and to evaluate one proposed method of artificial lift.

The data from this program was used to establish an economic basis by which several proposed methods of well unloading were proposed methods of well unloading were evaluated, and to project a production decline. These projected declines were used to establish a basis for the installation of a booster compressor.

It is anticipated that some method of controlled well unloading will have to be used in some, if not all, of the wells in this field before it is economically depleted. The methods, or method, used will be determined after the stabilized rate of production decline has been established with the wells producing at lower tubing pressures through the booster compressor.

From experience gained in this field, the use of 1-1/4-in. tubing in medium depth (8,000 to 10,000 ft) gas wells is recommended if they are low volume producers. Pressure drops at low rates of flow are not large and smaller casing strings can be used, reducing initial completion costs. The increased flow efficiencies developed in 1-1/4-in. tubing, and in some cases 1-in. tubing, provide an additional economic incentive to evaluate marginal sands that might otherwise be abandoned.

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