A Sinusoidal Pressure Response Method for Determining the Properties of a Porous Medium and Its In-Situ Fluid

Abstract

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the 46th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, held in New Orleans, Oct. 3–6, 1971. 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 presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is 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. 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 Solutions to the equations describing flow in porous media under sinusoidal pressure conditions are available in the pressure conditions are available in the literature. Very little use has been made of this theory and the experimental applications reported have dealt with gases and no flow through the media. Frequency response data from sinusoidal pressure experiments using liquids can be pressure experiments using liquids can be used to characterize the porous media and fluid properties. The lack of this type of data is probably due to the difficulty of generating the sinusoidal disturbances having sufficient frequency range and amplitude. Measurements were made using a synthetic oil in an unconsolidated medium. Equipment was designed to generate pressure sine wave whose upper frequency limit was in excess of 1,000 rad./sec. The core was equipped with high speed pressure transducers at various positions along the medium which measured the positions along the medium which measured the pressure response at a known flow rate. pressure response at a known flow rate. The experiments were designed to study the effect of pressure amplitude and frequency on the response of the system. Comparison of the theory and these experiments indicates that there are definite frequency limits which may be used if the equations are to adequately describe the data. As the frequency and or permeability increases, the inertial terms become important. This study shows that practical use can be made of existing theory to increase our ability to describe the flow of fluids in porous media. porous media Introduction The measurement of pressure transient responses is one of the few methods available for the reservoir to communicate its rock and fluid properties to an observer. Frequency response methods have been used by several investigators to determine rock and fluid properties. Experimental studies have been reported which used sinusoidal pressure inputs in gas filled porous systems with storage pores. Other porous systems with storage pores. Other investigators have used pluse testing methods to determine reservoir properties. Several methods have been proposed for describing the behavior of pressure transients in porous media.