Отправлено: 27.06.07 02:38. Заголовок: Пространственная взаиммосвязь систем трещин (моделирование и практика)

Connectivity of Spatially Correlated Fractures –
Simulation and Field Studies (SPE-107132)
M. Masihi* (Sharif U. of Technology) & P.R. King (Imperial College London)
SUMMARY
The nature of fluid flow in fractured reservoirs of very low matrix permeability depends on the
geometrical properties of fractures as well as the connectivity of the fracture network.
Percolation theory is the obvious tool to rapidly estimate the connectivity and its associated uncertainty
through some algebraic scaling relations. However, the usual scaling laws do not consider anisotropy,
fracture size distribution and fractures' interactions. We have recently addressed the effects of anisotropy
in orientation of fractures (SPE 94186) and fracture length distribution (SPE 100229) on the scaling law of
the connectivity. Poisson distribution of fractures assumed by standard percolation is also in contradiction
with the existence of fracture sets or the observed spatial correlation between natural fractures over scales.
In this study we first present a simple geomechanical fracture model with which we can
investigate the effect of fracture spatial correlation on the network connectivity. We assume that all
fracturing has happened and has achieved mechanical equilibrium which enables us to use entropy
arguments and statistical mechanics to model fractures. With this, we use the realizations of correlated
fracture networks in the basic methodology of the percolation and investigate the network connectivity. In
particular, the simulation results show that the scaling exponents of the connectivity are different from the
conventional, uncorrelated values.
We then use the field data of fractures exposed on the southern margin of the Bristol Channel
Basin to investigate the fracture spatial correlation, appears as cross correlation between fracture position
and its length or orientation. We also show that the connectivity predictions from the percolation approach
are in agreement with the results calculated from field data with the advantage that they can be obtained
very quickly. As a result this extends the applicability of percolation approach to correlated fractures which may be used for practical engineering purposes.

Авторы из уважаемой организации сделали интересную работу, которая мне не сильно прозрачна (по некомпетентности)
Проводится моделирование путем генерация системы трещин с последовательным уменьшением температуры в "машине Больцмана" причем правила коррекции углов, длин и раскрытий трещин задаются в явном виде
Сама энергия расписывается через попарное взаимодействие упругих трещин
Получаемые результаты анализируются по их взаимосвязи с результатами непрерывной перколяции
На реальном месторождении проанализированы системы трещин (в том числе их размер, число и связность)
В работе библиография в 35 наименований (включая и одну свежую публикацию авторов)