Sharif Digital Repository

The most common method of oil recovery is by displacement. By injecting water into wells, to push the oil to production wells, ultimately, the injected fluid breaks through at the production wells. Estimation of breakthrough time is important for the reservoir engineering calculation and the prediction of enhance recovery scenarios. Oil reservoirs are extremely complex, containing geological heterogeneities on all length scales which have a significant impact on hydrocarbon recovery. The conventional approach to investigate the reservoir performance is to build a detailed geological model, upscale it, and finally run flow simulation which is computationally very expensive. In... 

Water flooding is one of the improved oil recovery methods that has been used for past decades. The water flooding efficiency is calculated in two different scale; macroscopic scale and microscopic scale. The efficiency in macroscopic scale is called volume sweep efficiency (Ev) and in microscopic scale, displacement sweep efficiency (Ed). A special type of hydrocarbon reservoirs are composed of several permeable units in an impermeable shaley background in a way that hydrocarbon can just flow through the permeable units. The predominant feature of such reservoirs is continuity of permeable units that affecting the flow behavior. This simplification enables us to model such reservoirs by... 

Many processes in the petroleum engineering industry involve particle transport in oil and gas reservoirs including sand production, fines migration, and nanoparticle injection. In these processes it is important to understand where the particles are travelling in the reservoir and the impact that they have on the formation properties. Large particles can damage the formation and decrease permeability which reduces the productive capacity of the reservoir. During nanoparticle injection, forces at the pore level can cause retention of particles and prevent their recovery. In addition, due to the heterogeneity of typical reservoirs, it is difficult to predict how particles will spread across... 

The conventional approach to investigate the reservoir performance is to build a detailed geological model, upscale it, and finally run flow simulation which is computationally very expensive. In addition, during the early stage of life of a reservoir, due to the lake of certain data, this method is usually based on analogues or rules of thumb and not detailed reservoir modelling. Therefore, there is a great incentive to produce much simpler physically-based methodologies. The main focus of this thesis is to use percolation approach to estimate the uncertainty in the reservoir properties. This method considers a hypothesis that the reservoir can be split into either permeable (i.e.... 

Most of petroleum reservoirs of Iran are fractured reservoirs which has different properties, geometrical structure and drive mechanism in comparison with conventional reservoirs. The major difference is the existence of interaction between fractures and matrix respectively with a high and very low permeable (or imperable) medi. One simulation method for these fractures is discrete fracture network (DFN) modeling which is used in this study to investigate dynamic properties of these fractures. In this study, matrix is assumed as an impermeable media then dynamic properties like effective permeability of fracture network for different realization reservoirs are calculated and and evaluated by... 

Permeability is an essential parameter used for reservoir evaluation, simulation and management to optimize oil recovery. The conventional approach to estimate reservoir connectivity, conductivity, sweep efficiency and other critical information for decision-making is to build detailed geological models, which are then upscaled to a coarser grid where flow simulations are run. However, this takes many hours to be carried out even for a single realization practically. In practice, a very small number of realizations are considered and consequently the true uncertainty in the results is very poorly estimated. In this study, a statistical model of isotropic overlying sandbodies is used to... 

Percolation is a simple probabilistic model which exhibits a phase transition. Here, we study this critical model from properties of random curves which in the scaling limit, appear as features seen on the macroscopic scale, in situations where the microscopic scale is taken to zero. Among the principal questions are the construction of the scaling limit, and the discription of some of the emergent properties, in particular the behavior under conformal maps Over the past few years, SLE has been developed as a valuable new tool to study the random paths of the scaling limit of two-dimensional critical models, and it is believed that SLE is the conformally invariant scaling limit of these... 

The static and dynamic properties of a porous medium are highly dependent on its internal geometry. CT scan images are used to obtain porous media geometry. These images are not directly suitable for computational purpose. Because these images are not easy computable, the pore-throat network models are used to geometrical conversation. Extracting these models from CT scans is done using statistical-probabilistic methods based on image processing. In this study, new methods for extracting the 3D pore network model from 2D/3D CT scan images and pore connection detection are presented. In this method, the geometric static parameters of the rock, including the porosity, the porosity-based... 

In this research oil production decline curve of heterogonous reservoirs was investigated. Heterogeneity is modeled by percolation theory and using Petrel software and mass balance equations are solved by Eclipse simulation software. In primary production stage which oil flows up the reservoir spontaneously by reservoir high internal pressure, decline curve is exponential. Changes in the characteristic parameter of the exponential decline curve with occupation probability and permeable objects size were investigated.In secondary production stage, after reducing the natural production potential of the reservoir, water injection is used to increase and stabilize the pressure and increase the... 

Determining the time of breakthrough of injected water is important when assessing waterflood in an oil reservoir. Breakthrough time distribution for a passive tracer (for example water) in percolation porous media (near the percolation threshold) gives insights into the dynamic behavior of flow in geometrically complex systems. However, the application of such distribution to realistic two-phase displacements can be done based on scaling of all parameters. Here, we propose two new approaches for scaling of breakthrough time (characteristic times) in two-dimensional flow through percolation porous media. The first is based on the flow geometry, and the second uses the flow parameters of a... 

One of the most vital aspects of understanding the traffic phenomenon is scrutinizing the traffic transition status, such as the transition from free flow to congestion. The Percolation Theory is a renowned theory focusing on analyzing various network types to detect the critical zones, which are the zones including links that are important to control to improve stability. By calculating the quality indices of network links, the Percolation Theory can simulate the traffic percolation propagation in the network and determine possible critical zones for further analysis. Most studies in this field assume access to data of several traffic parameters for the entire transportation network, such...