HYDRAULIC FRACTURING in the CADDO-PINE ISLAND FIELD

ABSTRACT, 0.1

The application of the hydraulic fracturing process in the Annona Chalk formation in the Caddo-Pine Island Field, Caddo Parish, La., has created a new outlook on the development of this reservoir as an economic source for oil production. The reservoir has been greatly affected by faulting and/or fracturing during its geologic history, and the physical characteristics of the formation have made possible the successful hydraulic fracturing operation. These conditions have also caused the production to vary greatly between wells and have resulted in several different methods of drilling and completion practices b y the opera.tors.

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This paper describes briefly the geology, development history and present drilling'and completion practices, the results of the hydraulic fracturing process in stimulating the production from the reservoir. Production histories on several wells are presented to show results of the various completion techniques, and comparisons of the production from individual wells before and after fractu

INTRODUCTION, 1.1

Caddo-Pine Island field is located approximately 15 miles north of the City of Shreveport in Caddo Parish

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The production from the Chalk is associated with faulting and natural fracturing of the formation and is found in several fields in North Louisiana. The discovery well in the Caddo-Pine Island field was the Savage Bros. & Morrical No. 1 Offenhauser, which was completed March 28, 1905, in the Annona Chalk at a depth of 1,556 ft. The well was located near Oil City, La., in the center of the NE ¼ of the SW ¼ of Sec. 1 T20N, R16W, and had an initial production of 5 B/D of 34 gravity oil. The well was considered non-commercial by the operatores and was soon plugged and abandoned. However, this discovery led to further development. By the close of 1907 23 wells had been drilled—eight of which produced oil, 11 produced gas, and four were aabandoned. Development of the field continued at a rapid pace during the following years, and by 1918 the production reached a peak of 11 million bbl/year.

SIZE OF FIELD, 2.1

The producing limits of the caddo-Pine Island field are shown in Fig. 2 which includes the Chalk producing limits and the major Oil City fault. The outer limit c

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overs all producing reservoirs in the field. The Caddo-Pine Island field is the largest oil producing area in the State of Louisiana, covering roughly 80,000 acres on which more than 90,000 wells have been drilled during the past 50 years with an accumulative production of over 200 millions bbls of oil. The present field productive area is considered to be 36,000 acreas with a total of 4,882 producing wells, 266 different operators, and 1,161 individual producing tracts. The most prolific producing wells were completed in the Paluxy sand, and commonly called Woodbine, during the early development of the field, but rapid depletion of the reservoir occurred because the production was not restricted and the wells were allowed to produce at their maximum capacity.

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The characteristics of Chalk, as will be shown later, controlled the withdrawal rates from this horizon and sufficient oil remained in place to encouraged later development as completion techniques were improved. The productive area of Chalk prior to hydraulic fracturing operations was approximately 10,000 acres, but the present extended limits of Chalk production covers nearly 20,500 acres. The average spacing of the Chalk producing area is 5 acres per well, but many wells have been drilled on town lots and on closer spacing in the better producing areas of Chalk.

RESULTS, 3.1

Intensive drilling in the Chalk started after the successful application of the fracturing process; and from the first treatment during Jan., 1953, to July 1, 1955, 1,510 wells were completed and a great many wells recompleted by this method. In the extended Chalk producing limit there are 298 different operators, 905 individual tracts and 4,035 producing wells. The drilling of new wells and recompletion of older wells still continue at a rapid pace.

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To compare the production and number of wells at the start of fracturing operations with the present status, two two-months' periods were selected to obtain a monthly average and the results are as follows.

HIS, 4.1TORY

The peak production of 11 million bbl/year in 1918 had decreased to 1,606,424 in 1936. A gradual increase then occurred as a result of increased drilling activities and acid treatments so that by 1947 the annual production was 2,280,000 bbl. Increased drilling activities during 1953 and 1954, allong with hydraulic fracturing of both the new and old wells, resulted in an increase of production to 5,434,578 and 8,143,496 bbl for the respective years. Based on the average production of the two-months' period above, the production for the Chalk wells alone reached approximately 7 million bbl in 1955.

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The Caddo-Pine Island field is classed as a stripper producing area; therefore, it is important that every cost in drilling, completing, and operating the wells be held to an absolute minimum. The price obtained for crude oil from the field has played an important part of recent development, and is reflected in the increased drilling activities since 1946.

HYSICAL TICS, 5.1

The Caddo-Pine Island producing area is associated with a dome relating to and on the northern flank of the Sabine Uplift. The structure is a graben type completely faulted dome with over 2,500 ft of closure on the Ferry Lake Anhydrite. The primary uplift occurred at the close of the Lower Cretaceous period, was then followed by erosian and later by the encroachment of the Upper Cretaceous seas. The rest of the structure on the Lower Cretaceous beds is located in Sec. 14, T21N, R15W.