3D Physical Simulation of Water Flooding Characteristics of Buried Hill Reservoir with Different Fracture Systems

Abstract

In order to understand the water-flooding characteristics of different fracture systems in metamorphic rock buried hill reservoirs and the mechanism of improving water-flooding development effect, a three-dimensional physical model of fractured reservoirs is established according to the similarity criterion based on the prototype of metamorphic buried hill reservoirs in JZ Oilfield in Bohai Bay Basin. Combined with the fractured reservoir characteristics of JZ Oilfield, the water displacement characteristics of the top-bottom staggered injection-production well pattern in different fracture network mode and different fracture development degree of buried hill reservoir are studied. The experimental results show that: 1) the more serious the fracture system irregularity is, the shorter the water-free oil production period is and the lower the water-free oil recovery is. After water breakthrough of production wells, the water cut rises faster, and the effect of water flooding development is worse; 2) under the condition of non-uniform fracture development, the development effect of the bottom fracture undeveloped is better than that of the middle fracture undeveloped. Water injection wells are deployed in areas with relatively few fractures, while oil wells are deployed in fractured areas with higher oil recovery and better development effect.

Experimental Study on Waterflooding Characteristics of a Large-Scale Physical Low-Permeability Model Based on a Similarity Criterion

“…At present, constructing large-scale physical models for experimental simulation has become one of the important means of unconventional oil and gas research . By applying the similarity criterion, researchers have successfully achieved similarity in permeability anisotropy, matrix–fracture imbibition, dynamic system, and resistance system and constructed a large-scale 3D physical model, which can effectively reduce the uncertainties that are inherently present in reservoir numerical simulation. − However, it is important to note that low-permeability reservoirs are typically formed through extensive volume fracturing and prolonged water injection, resulting in the creation of irregularly distributed fractures on multiple scales. To address this complexity, the utilization of 3D solid models allows for simulation of reservoirs under various conditions, but currently prevalent 3D solid models are characterized by their large size, high cost, complex manufacturing process, demanding technical requirements, and limited popularity .…”