Papers by Keyword: Seepage Mechanics

Abstract: Buried mudstones general have undercompacted phenomenon. Undercompacted mudstones have the characteristics that the porosity and pore fluid pressure are abnormal bigger. In order to disclosure the seepage mechanics mechanism of undercompacted mudstones formation, this paper has summed up the seepage mechanics relationship when fluid flows through the mudstone, and has verified the relationships between the key physical quantities with the minimal pressure (pressure that can let the fluid flow in the mudstone) by the experiments in physics. This paper has also analysis the formations process of undercompacted mudstone. The result shows that, the flow regime of fluid in the mudstone is the low speed seepage, and it is not applicable by Darcy equation; the fluid what flow through the thick and heavy compacted mudstone has the big minimal pressure. At the beginning or during the deposit, the rule of fluid flow in the mudstone decides that the fluid inside of the mudstone is more difficult to flow out than the fluid surface of the mudstone, and the inside mudstone becomes undercompacted. Because of the undercompacted mudstone is more important for the exploration of oil and gas, it has theoretic and practical sense to analysis the formations mechanism of the undercompacted mudstone.

Abstract: A series of numerical simulations of hydraulic fracturing were performed to study the initiation, propagation and breakdown of fluid driven fractures. The simulations are conducted with a flow-coupled Rock Failure Process Analysis code (RFPA2D). Both heterogeneity and permeability of the rocks are taken into account in the studies. The simulated results reflect macroscopic failure evolution process induced by microscopic fracture subjected to porosity pressure, which are well agreeable to the character of multiple hydraulic fracturing experiments. Based on the modeling results, it is pointed out that fracture is influenced not only by pore pressure magnitude on a local scale around the fracture tip but also by the orientation and the distribution of pore pressure gradients on a global scale. The fracture initiation, the orientation of crack path, the breakdown pressure and the stress field evolution around the fracture tip are influenced considerably by the orientation of the pore pressure. The research provides valuable guidance to the designers of hydraulic fracturing engineering.