Field Tests With A Combination Fracturing And Formation Testing Method
Authors: Murphy W.C. 
Published: December 2007

Publication Rights Reserved

This paper was prepared for the Four Corners Regional Meeting to be held in Farmington, N.M., on Sept. 18–19, 1964, and at the 39th Annual Fall Meeting to be held in Houston, Tex., on Oct. 11–14, 1964, and is considered the property of the Society of Petroleum Engineers. Permission to published is hereby restricted to an abstract of not more than 300 words, with no illustrations, unless the paper is specifically released to the press by the Editor of the Journal of Petroleum Technology or the Executive Secretary. Such abstract should contain conspicuous acknowledgement 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 providing proper credit is given that publication and the original presentation of the paper.

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 combination fracturing-formation testing tool, a completely new concept to stimulate and test a well in the same operation, has been field tested. This technique employs a solid fuel propellant to force a stimulating fluid into the formation to alleviate existing wellbore damage or low permeability. The remainder of the formation test is conducted in the conventional manner.

The method of development and laboratory test results of this combination fracturing and formation testing technique are presented with expected stimulation rate, horsepower and pressure for certain conditions. Recommendations for the type and condition of the well that is the most applicable to this technique are made.

Results of field tests with illustrations are presented and discussed. Whenever possible this combination method was preceded by a conventional test in order to evaluate the effectiveness of the technique. A comparison of formation characteristics, production rate and well behavior as a result of the combination fracturing-formation testing technique are made.

Introduction

The petroleum industry is constantly seeking additional aids to help evaluate formations. Formation testing is one of the oldest and most conclusive methods of evaluating a potentially commercial zone; however, this method will not always reveal the true productive capacity of the formation. Many times a formation test will result in a very small recovery with an outward appearance of a barren zone. This low productivity may be the result of wellbore damage, low permeability or low flow capacity. Wellbore damage, the greatest and most common problem in predicting production, may result from many conditions. Wellbore damage may exist as an emulsion, swelling of water sensitive clays, bit disturbance or an invasion of mud filtrates from the drilling fluid. Anyone of the above sources of wellbore damage may drastically decrease the permeability of a formation to the extent that a normal formation test is inconclusive or produce misleading evaluation results when tested.

Low permeability is also a hindrance to a conclusive evaluation of a formation. A small recovery of rat hole mud is quite common when testing low permeability formations. The inability of these formations to produce under the existing formation characteristics and well conditions may not show an indication of hydrocarbons in the presence of commercial deposits.

In a typical well about 50 per cent of the total pressure drop within its drainage area will be within 10 to 15 ft of the wellbore.