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    hamed rahnema

    Controlled environment agriculture has the potential to enhance agriculture sustainability, a United Nations sustainable development goal. Enclosed agricultural facilities can be used in locations that cannot support field agriculture... more
    Controlled environment agriculture has the potential to enhance agriculture sustainability, a United Nations sustainable development goal. Enclosed agricultural facilities can be used in locations that cannot support field agriculture while reducing water usage and increasing productivity relative to open field agriculture. The primary challenges with operation arise from energy consumption to maintain the proper growth conditions. Membrane processes can reduce energy consumption by controlling temperature, humidity, and carbon dioxide concentration. Membrane processes also can minimize water consumption by enabling the use of non-conventional water resources and reducing wastewater production. The literature describing these applications is reviewed and opportunities for future innovation are discussed.
    Heavy oil recovery techniques often confront a significant challenge in in-situ asphaltene precipitation. This procedure significantly affects the characteristics of reservoirs and impedes optimal oil extraction. The purpose of this... more
    Heavy oil recovery techniques often confront a significant challenge in in-situ asphaltene precipitation. This procedure significantly affects the characteristics of reservoirs and impedes optimal oil extraction. The purpose of this research was to examine how hydrocarbon solvents affect asphaltene precipitation occurring naturally in the reservoir, as well as the resulting asphaltene content in processed oil. This was conducted using a laboratory-level dynamic model and the Solvent-Assisted Cyclic Steam Stimulation (CSS) method. Throughout this experiment, which comprised six cycles, the steam-solvent blend's pressure was consistently maintained close to 680 psi, and temperature was maintained at 500 °F at the injection point. The findings revealed crude oil cracking at this temperature and noticeable in-situ asphaltene precipitation during the solvent-assisted CSS process. Notably, asphaltenes demonstrated mobility within porous media, contributing to their production in subsequent CSS cycles. Compared to a steam-only CSS control experiment, a higher asphaltene content in the original oil was observed, indicating that thermodynamic changes during the experiments likely caused asphaltene cracking. To sum up, this research provides an understanding of the effects of heavy oil recovery methods that rely on solvents on the precipitation of in-situ asphaltene and the content of asphaltene in the refined oil.
    Research Interests:
    This study explores the effectiveness of alcohol injection as a stimulation treatment to mitigate water blockage in the vicinity of the wellbore. Over the years, water blockage has emerged as a recurring challenge within the oil and gas... more
    This study explores the effectiveness of alcohol injection as a stimulation treatment to mitigate water blockage in the vicinity of the wellbore. Over the years, water blockage has emerged as a recurring challenge within the oil and gas industry, leading to diminished well productivity. In a commingled reservoir with multiple layers, when a producing well is shut-in for well intervention or workover, water may encroach from water zones into the oil-bearing formations through the wellbore due to pressure differences between the layers. Water encroachment can have a significant impact on the production of a well. It can reduce the oil production rate, increase the water cut, and shorten the well's lifespan. Therefore, it is essential to take steps to mitigate the water encroachment effect in commingled reservoirs. This study explores the use of alcohol injection to reduce transition time and remediate formation damage in commingled oil reservoirs. Limited studies have shown that alcohol has the potential to enhance fluid relative Permeability in gas condensate reservoirs and reduce condensate banking near the wellbore. However, this approach has not yet been tested in commingled oil reservoirs. A series of core flooding tests were conducted using Berea sandstone cores and a Texan light crude oil sample. The core flood setup was designed to represent the water blockage condition in the formation. Two different alcohols were tested: isopropyl alcohol (IPA) and Methanol. Experimental results showed that mutual solvents significantly reduce water blockage and shorten the transition period. However, asphaltene precipitation may become a problem with increasing the molecular weight of injected alcohol.
    Vapor extraction (Vapex) is an emerging technology to produce heavy oil and bitumen from subsurface formations. Single well (SW) Vapex technique uses the same concept of Vapex process but only with one horizontal well. In this process... more
    Vapor extraction (Vapex) is an emerging technology to produce heavy oil and bitumen from subsurface formations. Single well (SW) Vapex technique uses the same concept of Vapex process but only with one horizontal well. In this process solvent is injected from the toe of the horizontal well with oil production at the heel section. The main advantage of SW-Vapex process lies in the economic saving and applicability in problematic reservoirs, where drilling of two horizontal wells is impractical. The performance of SW-Vapex seems to be comparable with dual horizontal Vapex process using proper optimization schemes. This study is grouped into two sections: (i) a screening study of early time operating performance of SW-Vapex and (ii) a sensitivity analysis of the effect of the reservoir and well completion parameters. Simulation results show that solvent injection rate can be optimized to improve oil production rate. Higher injection rates may not necessarily lead to increase in production. This study confirms that SW-Vapex process is very ineffective in reservoirs with high oil viscosity (more than 1,500 cp) and thin formations (less than 10 m).