Quantification of permeability stress-sensitivity in tight gas reservoir based on straight-line analysis

Production data analysis for a tight gas reservoir has become the forefront of research due to its important role in formation/fracture characterization. In particular, the straight-line analysis for linear flow is a popular research area because linear flow is the dominant transient flow for a multi-fractured well in a tight gas reservoir. However, because the permeability of some tight gas reservoirs is sensitive to stress, applying a traditional straight line analysis procedure to these reservoirs may lead to significant errors. To better analyze and develop a stress-sensitive tight gas reservoir, the permeability modulus, which can be used to quantify the permeability stress-sensitivity, is a very important parameter. Currently, the permeability modulus is mainly determined using laboratory experiments, which is expensive and idealistic. Therefore, an easier and more accurate method is required to quantify the stress-sensitivity of the permeability and to evaluate the properties of formation/fracture. s paper, the deviation caused by applying the traditional straight-line analysis method to a stress-sensitive tight gas reservoir is analyzed. Next, based on corrected pseudo-parameters and the concept of cut-and-trial, a new procedure used to determine the permeability modulus and the formation/fracture parameters is introduced in detail. In this process, the concept of average pressure in the region of influence is also considered and improved. This new procedure is proved to be accurate after validation by both synthetic and field examples.