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Experimental and Numerical Modelling of Deformation and Fluid Flow |
1 Conoco Inc., P.O. Box 2197, Houston, Texas, 77252-2197, USA
2 Houston Advanced Research Center, 4800 Research Forest Drive, The Woodlands, Texas 77381, USA
3 Conoco Inc., P.O. Box 1267, Ponca City, Oklahoma 74602-1267, USA
4 Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
5 Texas A & M University, Department of Petroleum Engineering, College Station, Texas 77843-3116, USA
6 Mackay School of Mines, University of Nevada, Reno, Nevada 89557-0047, USA
Experience has shown that fractures and faults within a given array are not all equally conductive or well-connected. To investigate new techniques for locating conductive fracture flow paths, a series of high resolution (1 to 10 kHz) crosswell and single well seismic surveys and interference tests were conducted in a shallow five spot well array penetrating a fractured limestone formation. Two inverse approaches for constructing fracture flow models were applied to the interference test data. Both approaches successfully reproduced the transient pressure behaviour at the pumping and observation wells and indicated a preferential fracture flow path between two wells aligned in an east-northeast direction, the dominant direction of fracturing mapped in the area. Crosswell and single well seismic experiments were performed before and after air injection designed to displace water from the fracture flow path and increase seismic visibility. The crosswell experiments showed that replacement of water with gas produces significant changes in the seismic signal. The single well reflection surveys were able to precisely locate the position of the fracture flow path. This location was confirmed by core from a slant well which intersected a single open fracture at the targeted depth.
