Petroleum Engineering – Reservoir
Mehdi Bahari Moghaddam; Seyyed Alireza Kamani
Abstract
An essential transport characteristic that links a substance's molar (mass) flux to its concentration gradient is the molecular diffusion coefficient. For modeling and performance forecasting of solvent-aided recovery processes of heavy oils such as VAPEX and SAGD; a reliable and accurate estimation ...
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An essential transport characteristic that links a substance's molar (mass) flux to its concentration gradient is the molecular diffusion coefficient. For modeling and performance forecasting of solvent-aided recovery processes of heavy oils such as VAPEX and SAGD; a reliable and accurate estimation of the molecular diffusion coefficient is a crucial input. Despite the importance of this parameter, there is no approved way to measure it, especially in systems with heavy oil and gaseous solvents that have limited solubility. This can be as a result of the intricacy of experimental measures and the challenge of analyzing experimental data. There are two direct and indirect methods for measuring the diffusion coefficient, the direct method has not been addressed because it is expensive and time-consuming. Indirect methods include Constant-Volume Methods (Pressure Decay), Constant-Pressure, Refractive Index, Nuclear Magnetic Resonance (NMR), X-ray Computer-Assisted Tomography (CAT), Pendent drop and Microfluidics. The advantage and disadvantages of these experimental methods established for diffusivity measurements of the gaseous solvent in heavy oil systems are discussed in this article. According to the investigations carried out in this study, the Constant-Volume Methods (Pressure Decay) with the least error percentage (1.05%) was chosen as the best method for measuring the diffusion coefficient. The diffusion coefficient of light and heavy oil was compared, and light oil has a higher diffusion coefficient.
Petroleum Engineering – Reservoir
Vahid Karamnia; Siavash Ashoori
Volume 10, Issue 1 , January 2021, , Pages 107-126
Abstract
< p>One of the most important factors through the miscible gas injection process is to determine the Minimum Miscibility Pressure. According to the definition, the minimum miscibility pressure is the minimum pressure at which, at a constant temperature, the oil and gas injected can dissolve together ...
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< p>One of the most important factors through the miscible gas injection process is to determine the Minimum Miscibility Pressure. According to the definition, the minimum miscibility pressure is the minimum pressure at which, at a constant temperature, the oil and gas injected can dissolve together to form a single phase. This pressure is typically abbreviated as MMP. Among the available methods for determining the minimum miscibility pressure, laboratory methods including slim tube test and ascending bubble apparatus test are more widely utilized. Although the mentioned tests have high measurement accuracy, they are very time consuming and expensive. Therefore, the determination of the minimum miscibility pressure is usually done using computational and simulation approaches that also have high accuracy. Conducting PVT tests and determining their MMP using slim tube method was previously performed. In this study, the minimum miscibility pressure of reservoirs was determined by applying three methods of simulation with PVTi software, simulation with Eclipse 300 software and using Empirical Correlations. By comparing the obtained results and the laboratory results, it was revealed that the simulation by Eclipse 300 is regarded as the fastest and most accurate approach.
Petroleum Engineering
Mohammad Abdideh; Yaghob Hamid
Abstract
Cap rocks are dams which can prevent the upward movement of hydrocarbons. They have disparities and weaknesses including discontinuities, crushed areas, and faults. Gas injection is an effective mechanism for oil recovery and pore pressure. With increasing pore pressure, normal stress is reduced, and ...
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Cap rocks are dams which can prevent the upward movement of hydrocarbons. They have disparities and weaknesses including discontinuities, crushed areas, and faults. Gas injection is an effective mechanism for oil recovery and pore pressure. With increasing pore pressure, normal stress is reduced, and the integrity of impermeable boundaries (cap rock, fault, etc.) becomes instable. A successful strategy for reservoir development is the inevitable necessity of conducting geomechanical studies and modeling the reservoir. The construction of a comprehensive geomechanical model, including the stress state is a function of depth (direction and amount), physical properties of the reservoir rock and its formations (rock resistance and elastic moduli), pore pressure estimation, and description and distribution of fractures and faults. In this work, analytical and numerical methods have been used in geomechanical modeling, and the data used for modeling and petrophysical information are downhole tests. The geomechanical modeling of gas injection into the reservoir and, simultaneously, the operation of Asmari reservoir and Marun oilfield cap rock in the southwest of Iran were carried out. The threshold of reactivating faults and the critical pressure of induced fracture were calculated, and the results were presented as analytical and numerical models. Moreover, in addition to analyzing the stress field at depths, the resistance parameters of the formations were determined. The results showed that the most changes and instabilities were around the wellheads, fractures, and the edges of the field.
