Fracture Containment Analysis Conducted on the Benson Pay Zone in Columbia Well 20538-T

Brechtel, C.E., Abou-Sayed, A.S., and Jones, A.H.
Source: 2nd East Gas Shales Symposium (Morgantown, W VA, 10/16/1978) Proceedings PP 264-272, October 1978 (METC/SP-78/6( Vol. 1)); Abstract no 7393, Energy Res Abstract V 4, No 4, P 787, 2/28/1979 (ISSN 01603604) (AO).


A series of laboratory and field tests have been performed to assess the capability of shale layers above and below the Benson Sandstone to contain a hydraulic fracture that would be created in the Benson pay zone . The laboratory tests revealed that the contrast in elastic moduli between the Benson and surrounding shale layers is unfavorable for such fracture containment . The in situ stress measurements indicated that the minimum in situ stress in the overlying shale layer is 480 psi greater than in the Benson Sandstone . On the other hand , the stress in the shale below the Benson Sandstone was only 180 psi greater . Since these stress contrasts enhance fracture containment , the situation was analyzed to predict the maximum bottom hole treating pressure required to achieve limited fracture extent outside the Benson pay zone . The containment analysis was based upon a limited incursion of the fracture into the upper shales of 5 to 10 feet and 40 to 100 feet into the lower shales . The maximum bottom hole treating pressure for nese control frad ire incursions were calculated for different fracturing fluids , and indicate a low range in permissible treating pressures .