Um modelo quase-analitico para simulação tridimensional de propagação de fratura hidraulica

AUTOR(ES)
DATA DE PUBLICAÇÃO

1996

RESUMO

Several models for the development of a fully three-dimensional hydraulic fracturing simulator have been described in the literature. However, most of them result in systems that require computational efforts not compatible with the direct application in the field. In order to attenuate this problem, simplified assumptions are introduced, resulting in pseudo three-dimensional models that allow simulations in real time. This dissertation describes the development of a model for numerical simulation of hydraulic ftacture propagation, assuming that the ftacture is planar and elliptical. Analytical expressions developed by Shah and Kobayashi are used for the determination of stresses, strains and stress intensity factors. These expressions assume that the net pressure in the ftacture can be represented by a polynomialof third degree, as follows:p(x,z) = P IND. 00 + P IND. I0 POT. X + P IND. 01 POT. Z + P IND. 20 POT. X POT. 2 + P IND. 11 POT. XZ + P IND. 02 POT. Z POT. 2 + P IND. 30 POT. X POT. 3 + P IND. 21 POT X POT. 2 Z + IND. 12 POT. XZ POT. 2 + P IND. 03 POT. Z POT. 3 . The same basic assumption was also used by Palmer, Luiskutty, Boutéca and Rueda, although with diferent numbers of terms in the polynomial. The current model is based on Rueda s work, and allows the simulation of layers with confining stress contrasts that are not necessarily syrnmetric with respect to the horizontal axis of the ellipsis. The results quality is poor when we do not have syrnmetrical confining stress cont (asts. Differents chemes are tested for the implementation Carter s approach for the leakotI, and for the computation of average apparent viscosity when non-Newtonian fluids are considered. Two differents propagation criteria are tested and compared. Both of them use simplified approaches to compute the relative extensions among the points on the fracture front, based on the stress intensity factors. An attempt to apply an energy based criterion was performed. However, the implementation was discontinued due to dificulties in developing a reliable algorithm

ASSUNTO(S)

simulação (computadores) mecanica da fratura engenharia de petroleo

ACESSO AO ARTIGO

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