Field Use of "Superfrac" - A New Hydraulic Fracturing Technique
Authors: Matthews T.M. 
Published: December 2007

This paper was prepared for the 44th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Denver, Colo., September, 28-October 1, 1969. 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 publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor 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.

Abstract
"Superfrac" is a new hydraulic fracturing technique described by Kiel which involves fracturing wells with mixtures of viscous oil and water carrying large propping agents. In the process the water provides an annular ring in the wellbore which minimizes friction losses and pumping horsepower requirements and permits the generation of long, wide, highly permeable fractures.
The present paper summarizes the field use of "Superfrac" in the first 248 field jobs for Humble. Overall, the technique has been found to be highly successful in stimulating oil wells with 237 jobs on oil wells giving an initial production increase of 13,697 BOPD and a stimulation ratio of about 3 on the basis of production volumes. These results have been obtained on jobs conducted throughout the United States and are discussed according to geographical area. Examples noteworthy results have been experienced when using "Superfrac" in deep wells and in highly permeable reservoirs. The technique is marketed under the names of "Super Frac", "Superfrac", and "Super Sand Frac." For convenience in this paper, it will be referred to as "Superfrac".

Introduction
Hydraulic fracturing is a stimulation technique that has become widely used by the oil industry since its introduction about 20 years ago. In a hydraulic fracturing treatment, fluid is injected into the well at rates higher than the reservoir matrix will accept. Rapid injection produces a buildup in wellbore pressure until a pressure large enough to overcome rock stresses is reached. At this pressure, failure occurs allowing a crack or fracture to be formed. Continued fluid injection with selected proppants results in a high conductivity crack in the formation and thereby well stimulation.
The key to stimulate by fracturing is altering the flow pattern of the reservoir from radial to one which approaches linear flow. McGuire and Sikora conducted analog simulations of the productivity of vertically fractured wells. Their results are the basis for predicting the stimulation available from fracturing (Fig. 1). The degree of stimulation (productivity index ratio) is a function of fracture conductivity relative to formation conductivity and propped fracture length as it relates to drainage radius. It is the propped fracture length and fracture conductivity propped fracture length and fracture conductivity that are of primary importance in effective fracture design.