Abstract: Prediction of Fluid and Reservoir Properties From Minifrac Tests

ISPAS, ION, Consultant

One of the most significant contributors to the oil and gas industry as a primary means of well production increase, is the hydraulic fracturing treatment. The dimensional and propagation characteristics of the hydraulic fracture constitute valuable information for a proper design of the fracturing treatments. Therefore a correct calibration of such operations is very important, and to ensure this, mini-fracture treatments are used. Many models, describing the mathematics and application of a mini-fracture have been developed. However, a significant number of assumptions limit their applicability, and consequently often times they can not be used successfully for the delineation of fluid and reservoir properties necessary for the calibration of the actual fracturing operation.

This work was undertaken to provide a more realistic and practical model that can be used for the prediction and determination of fluid and reservoir properties such as fluid efficiency, leak-off coefficient, fracture half-length, fracture width, reservoir permeability, and filter-cake resistance. The main contribution of this model consists of: (1)consideration of the effects of the spurt loss which can be a significant contributor of the leak-off process in reservoirs with medium or high permeability, and (2) sensitivity analysis to enhance the applicability of the model by indicating which parameters are playing a major role in the interpretation of a calibration treatment.Field cases of minifrac tests are used for the evaluation of the methodology presented in this work.

AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California