Effect of Incomplete Fracture Fill Up at the Wellbore on Productivity Ratio
Authors: Smith John E. 
Published: December 2007

This paper was prepared for the 48th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Las Vegas, Nev., Sept. 30-Oct. 3, 1973. 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 theory concerning the effect of incomplete fracture fill-up at the wellbore on productivity ratio is summarized in this paper. It is pointed out that a positive effort to achieve good propping agent packing at the wellbore can result in a productivity ratio of up to twice that which would productivity ratio of up to twice that which would have been attained if the fracture were allowed to close. Also discussed are present fracture treatment methods and proposed modifications to accomplish better fill-up near the wellbore. Data are presented which indicate to obtain good fracture-to-well communication, fracturing treatments should be designed and performed using a controlled screen-out method, and a means of implementing controlled screen-out treatments is outlined.

Results presented emphasize the importance of complete fracture fill-up near the wellbore. Money spent in increasing fracture conductivity will be wasted unless good fracture-to-well communication is achieved. Techniques to insure that the fracture is filled at the wellbore should be applied in all fracturing treatments except where prohibited by unusual conditions (weak pipe, fracturing under a packer, etc.).

Introduction

The process of hydraulic fracturing has been used extensively for well stimulation by the petroleum industry for over two decades. During petroleum industry for over two decades. During this time the ability to successfully execute a fracturing treatment has increased to the point where very few mechanical failures point where very few mechanical failures currently occur. In addition, the development of treatment design and evaluation procedures has evolved to the point where fracturing is now considered a science rather than an art. As the science progresses, new problems concerning the design and evaluation of optimum fracturing treatments arise frequently. One of the most pertinent of these problems is what effect pertinent of these problems is what effect incomplete fracture fill-up at the wellbore has on productivity ratio. Solution of this problem will be useful in treatment planning to accomplish desired production goals.

The purpose of this paper is to evaluate the effect of incomplete fracture fill-up at the wellbore on productivity ratio, and to present the findings of a controlled screen-out fracturing program which was initiated for the purpose of obtaining field results to purpose of obtaining field results to substantiate the theory presented in the paper.