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Numerical evaluation of hydraulic fracturing experiments

Nouri, A ; Sharif University of Technology | 2003

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  1. Type of Document: Article
  2. Publisher: 2003
  3. Abstract:
  4. Improved methods of constructing wells and producing wells are one of the keys to increasing field profitability. In the areas of well construction and well productivity optimization, many of the problems encountered are related to the geomechanics of the reservoir and the overlying layers; these problems include well-bore stability, sand production and hydraulic fracturing. Hydraulic fracturing is a complicated phenomenon in which deformation of the porous medium and fluid leak-off to the surrounding area take place simultaneously. Their interaction, therefore, must not be overlooked. In the past, some experimental researchers performed laboratory investigations on the phenomenon of hydraulic fracturing. Nevertheless, because of the lack of detailed data and in order to investigate the mechanism of failure, several laboratory tests were conducted on compacted hollow cylindrical specimens under different confining pressures. These experiments included both cohesive and cohesionless materials. In order to analyse the experimental data and model the hydraulic fracturing experiments, the fluid leak off with mechanical deformation of the porous material were simulated in a fully coupled manner. In this investigation, a developed finite element scheme numerically simulates the hydraulic fracturing tests. A hyperbolic model as well as an elastic model related to the minimum effective stress is used for soil behavior modeling. The initiation of fracture and the final destruction of the samples were modeled using the Mohr-Coulomb criterion. A comparison between the experimental and numerical results provides insight into the hydraulic fracture phenomenon. Finally, some explanations on the experimental works based on the numerical results are presented. The numerical results show that using a hyperbolic model and a Mohr-Coulomb based failure criterion very well models both initiation and propagation of the hydraulic fracture in the sample. Moreover, the hydraulic fracture pressure of the sample from numerical modeling linearly changes with the confining pressure applied on the sample. This pattern was proved by experimental modeling
  5. Keywords:
  6. Analytic hierarchy process method ; Three-dimensional geological model ; In situ stress ; Fracability evaluation
  7. Source: Canadian Society for Civil Engineering - 31st Annual Conference: 2003 Building our Civilization, Moncton, NB, 4 June 2003 through 7 June 2003 ; Volume 2003 , 2003 , Pages 2309-2312 ; 1894662040 (ISBN); 9781894662048 (ISBN)