The Influnence of a Fracture Tip on Two-Phase Flow Displacement Process

Open Access
Author:
Alajmi, Abdullah Fahad Faleh
Graduate Program:
Petroleum and Natural Gas Engineering
Degree:
Doctor of Philosophy
Document Type:
Dissertation
Date of Defense:
May 05, 2003
Committee Members:
  • Abraham S Grader, Committee Chair
  • Turgay Ertekin, Committee Member
  • Phillip Michael Halleck, Committee Member
  • Derek Elsworth, Committee Member
  • Michael Adebola Adewumi, Committee Member
Keywords:
  • experimental work.
  • Fracture
  • dispalcement
  • porous media
  • simulation
Abstract:
This work focuses on multi-phase flow in the presence of a fracture tip. Fluid flow interactions between a fracture and the surrounding matrix are not well documented in the literature, especially in the case of a fracture tip. This work studies two-phase fluid flow (Water-Oil) displacements in layered Berea Sandstones that have been artificially fractured with a single extensional fracture perpendicular to the natural layers. Two experiments are considered in this work. In the first experiment, the fracture was induced at the inlet end of the sample and it spanned the first third of the core. Thus, the diverging flow at the tip of the fracture was studied. In the second experiment, the fracture was induced at the outlet end of the sample and it spanned about one third of the core. Multi-phase fluid flow convergence to the fracture tip was studied in this experiment. The temporal and spatial saturation distributions of the two cases were determined using x-ray computed tomography, CT. The 4D-CT experimental data and recovery information were used as the basis for simulation in an effort to determine the interaction of fracture-matrix environment with multi-phase flow. At the tip of the fracture, the two experiments showed different fluid flow patterns. The presence of the tip of the fracture in both experiments influenced the displacement path along each layer. The presence of the fracture tip is essential for highlighting the property contrast between the natural layers in the sample, much more than in a displacement process without a fracture. Matches of the simulation results to the experimental data showed that when the fracture is at the inlet end, fluid diverges from the fracture to the matrix along the entire length of the fracture. The displaced phase is delayed in the regions neighboring the fracture and it preferentially flowed in the outer regions of the core. Understanding multi-phase fluid flow in fractured rocks is essential for designing and optimizing hydrocarbon recovery processes. The fluid flow interactions between the fractures and the matrix have a significant impact on displacement processes. This work provides modeling results and experimental observations that explain some of the displacement processes around a fracture tip.