Pin-Point Sandfracturing - A Method of Simultaneous Injection into Selected Sands
- W.B. Murphy (Cia. Shell de Venezuela) | A.H. Juch (Cia. Shell de Venezuela)
- Document ID
- Society of Petroleum Engineers
- Journal of Petroleum Technology
- Publication Date
- November 1960
- Document Type
- Journal Paper
- 21 - 24
- 1960. Original copyright American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Copyright has expired.
- 2.4.3 Sand/Solids Control, 4.1.2 Separation and Treating, 2.2.2 Perforating, 1.2.3 Rock properties
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The conventional sandfracturing techniques first adopted by the Lagunillas Land Dist. of Cia. Shell de Venezuela in its Eocene wells, which had been perforated with four holes/ft over the full NOS interval, resulted in production increases which averaged some 700 per cent.
However, recent developments in completion technique not only have reduced completion costs, but also have resulted in a further appreciable increase in production. Production rates of the new completions over the first year after sand fracturing are some 60 to 90 per cent higher than those of the "conventional" completions.
It is believed that, by having a limited number of perforations and always providing an injection capacity which theoretically is greater than the total capacity of the perforations, there is a greater likelihood of fracturing all sands simultaneously.
It is estimated that the technique reduces completion costs by $3,700.
Productive prospects have been known to exist in the Eocene formations on the eastern shore of Lake Maracaibo for some time, but it was not until the successful introduction of sandfracturing as a stimulation technique that these could be economically exploited. Cia. Shell de Venezuela's Eocene land activity has, in the main, been concentrated in the Lagunillas, Tia Juana and (to a lesser extent) Cabimas fields; (these three fields comprise the company's Lagunillas Land Dist. By Feb., 1959, a total of 155 Eocene wells had been completed as economic producers after receiving a sandfracturing stimulation treatment.
The productive shallow Eocene (B.1 sand), encountered between 1,000 and 3,000 ft, has gross intervals from 50 to 1,000 ft and is composed of interbedded shales and fine- to medium-grained consolidated sandstones. The sandstones make up, on the average, some 50 per cent of the section, but permeability (as shown by the Microlog) is restricted to some 60 per cent of the total sandstone development. The shallow Eocene is productive in the Lagunillas, Main Tia Juana and Cabimas fields.
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