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Rabbani A.,Sharif University of Technology | Amani S.,Petroleum University of Technology
Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources

Plasma impulse technology (PIT) is one of the most innovative methods among the oil recovery enhancement (EOR) jobs. Although the low cost and persistent effects of this method has attracted researchers attentions to its self, the governing mechanisms of reservoir remediation in this method are still shrouded in mystery. This study presents a brief discussion on probable thermal mechanisms which govern the interaction between reservoir formation and plasma impulse jet. Minerals dissociation, opening the fused pathway and organic deposits melting seem to be of the most important thermal effects. Source

Jamaloei B.Y.,University of Calgary | Kharrat R.,Petroleum University of Technology | Torabi F.,University of Regina
Society of Petroleum Engineers - Canadian Unconventional Resources and International Petroleum Conference 2010

Post-primary recovery from some mobile heavy-oil reservoirs in Western Canada cannot be improved using thermal methods due to environmental concerns and technical difficulties. Moreover, miscible gas injection suffers from low initial production rates, premature breakthrough, and possible, formation damage. Low-tension polymer flooding (LTPF) can be an alternative in these reservoirs. However, a major technical challenge in LTPF is that a fingered displacement front may occur. This instability reduces displacement efficiency and may invalidate normal method of simulating LTPF performance based on relative permeability and capillary pressure concepts. Also, it introduces an additional scaling requirement for using results of experimental tests in larger scales. Therefore, it is important to predict the nature of instability, to avoid viscous fingering, or, where it is inevitable, to be capable to include it as an additional factor in modeling displacement. Previous experiments of viscous fingering in immiscible displacements have been conducted in presence of high single-phase permeabilities and linear displacement schemes. The question is whether previous findings are valid in displacement schemes similar to oil-field patterns (e.g., five-spot) in which one should deal with varying velocity profiles from injector(s) to producer(s). Hence, the effect of dispersion caused by varying velocity profiles has not been tested completely on viscous fingering. To help understand viscous fingering in LTPF in heavy oil reservoirs and to overcome the aforementioned limitations, we conducted experiments in low-permeability, one-quarter five-spot patterns. Foremost parameters including oil recoveries at different times to breakthrough, ultimate oil recovery, pressure drops, cumulative saturation profiles, mean local saturations, fingers length and width, dynamic level of bypassing, dynamic population of fingers, rate of growth of population of fingers and number frequency of the fingers were measured. We have correlated some of these parameters with displacement time and front position. Analysis of experimentally-observed fingering patterns of LTPF in this study is the most detailed interpretation performed to date, which provides new insights into the onset of fingering and fingers development. Results would help numerical simulation and stability theory to satisfactorily reproduce qualitative and quantitative features of finger growth. Copyright 2010, Society of Petroleum Engineers. Source

Alavi S.M.,Petroleum University of Technology | Aryanzadeh A.,Petroleum University of Technology
7th EAGE Saint Petersburg International Conference and Exhibition: Understanding the Harmony of the Earth's Resources Through Integration of Geosciences

Laboratory measurement of relative permeability including steady state and unsteady state methods are expensive and time consuming. Due to these shortcomings, several models for predicting and obtaining two phase relative permeabilites have been developed in literature. This study involves the comparison of different oil and gas relative permeability models with three experimental datasets from laboratory tests conducted on Iranian carbonate rocks. The comparison method includes a statistical approach for determining the best model performance applied to the model predictions. It found that Koederitz model gives closest fit to relative permeability ratio obtained from experimental data sets and it is followed by Wylie and Mohamad Ibrahim. Source

Al-Ghamdi A.,University of Calgary | Chen B.,Yangtze University | Behmanesh H.,Petroleum University of Technology | Qanbari F.,Petroleum University of Technology | Aguilera R.,University of Calgary
SPE Reservoir Evaluation and Engineering

Many naturally fractured reservoirs are composed of matrix, fractures, and nontouching vugs (there can also be any other type of nonconnected porosity that can occur; for example, in intragranu-lar, moldic, and/or fenestral porosity). An improved triple-porosity model is presented that takes these different types of porosities into account. The model can be used continuously throughout a reservoir with segments composed of solely matrix porosity, solely matrix/fractures, solely fractures/vugs, or the complete triple-porosity system. The model improves a previous triple-porosity algorithm by handling rigorously the scale associated with each: matrix, fractures, and vugs. This permits determining more-realistic values of the cementation or porosity exponent, m, for the composite system and consequently improved values of water saturation and reserves evaluations. The values of m for the triple-porosity reservoir can be smaller than, equal to, or larger than the porosity exponent of only the matrix blocks, mb, depending on the relative contribution of the vugs and fractures to the total porosity system. It is concluded that not taking into account the contribution of matrix, fractures, and vugs in the petrophysical evaluation of triple-porosity systems can lead to significant errors in the determination of m, and consequently in the calculation of water saturation, hydrocarbons in place, and recoveries, and ultimately can lead to poor economic evaluations-either too pessimistic or too optimistic. This is illustrated with two examples from Middle East carbonates. Copyright © 2011 Society of Petroleum Engineers. Source

Shahvar M.B.,Petroleum University of Technology | Kharrat R.,Petroleum University of Technology
Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources

After drilling a well, early flow unit characterization might be very useful for further reservoir developments. Up to now, most of the methods suggested for flow unit identification are based on using core data. In the proposed approach in this study, core data are again considered as the basis but extending the flow units to other wells are done using gamma ray and resistivity logs that are interpreted in a new way. Using core data, normalized cumulative flow zone index (NCFZI) is calculated for each data point. Studying this parameter in the time-scale space of wavelet reveals exact numbers of the flow units along the depth. Wavelet transformation and reconstruction of gamma ray signal shows that this log type exhibits the locations of flow units changes very well, therefore can be used in uncored wells for early characterization. To determine the quality of each flow unit, wavelet transform of resistivity logs that are found capable of indicating high-permeability zones are utilized separately for each flow unit. Highfrequency signals of resistivity logs correspond to each unit are an indication of high potential of that unit to fluid flow. Source

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