Oil recovery using Smart Water technology (SWF) can be maximized by optimizing the composition of injected water. Brine optimization is also believed to improve Polymer Flooding (PF) performance. The present study aims to assess and define the potential impact of combining Smart Water with Polymer Flooding, based on the sulphates presence in formation/injection water and rock composition. In this work, we study the impact of sulphates (sodium sulphates) on polymer viscoelasticity and its performance in porous media, based on oil recovery and pressure response. Brine composition is optimized after having synthetic sea water (SSW) as a base brine. Brine optimization is performed by doubling the amount of sulphates, whilst diluting (in fresh water) the SSW-brine to a tenth of its initial concentration. Thus, four brines were utilized: 1) SSW (formation water), 2) SSW but double sulphates, 3) SSW/10 and 4) Brine 2/10. The workflow included core plugs aging prior core flooding. Secondary tertiary and quaternary mode experiments were performed to evaluate the feasibility of applying both processes. The SSW-brine optimization (a tenth of its initial concentration) resulted in a salinity of 4.2 g/L which is in good agreement with previous studies (≤5 g/L), to guarantee additional oil recovery using SWF. Polymer rheological characterization was performed over wide range of shear rates and temperatures. Sodium sulphates showed increase in polymer viscosity as compare to sodium chloride or divalent cations. Enhancement in polymer linear viscoelasticity is observed with an increase in sulphate ions concentration. Furthermore, viscosity analysis over temperature has advocated to perform the core flood experiments at 45°C. Fluids were optimized/selected using a comprehensive rheological evaluation (ηoilηpolymer=2). Optimized Smart Water with higher amount of sulphates ions has shown additional oil recovery in both secondary and tertiary mode. Moreover, polymer injection in tertiary mode after smart water injection has shown significant additional oil recovery. This study focuses on the influence of sulphates ions on SWF and PF performance for application in sandstone reservoirs. Previous studies have mainly focused the evaluation of sulphates ions impact only in carbonate reservoirs. It is of importance to further understand/clarify the effect of sulphates for field applications of SWF and PF combined. This in turn, could lead to improve the economics of project performance, by means of incremental oil and the less polymer required.
A water hammer is a common problem occurring in water distribution systems, such as water transport pipelines. Transient hydraulic occurs in the distribution system, which may cause system failure due to pipe collapse or bursting. In this paper, an irrigation pipeline system of the proposed Taq-Taq dam (north-eastern part of Iraq) is used to represent the common situation of lifting water from the dam reservoir to another higher reservoir (irrigation project reservoir) through a pipeline. The transmission line is subject to a potential water hammer where the water level in two main reservoirs is controlled at both ends. The hydraulic simulation model used in the design and analysis of hydraulic and transverse behaviour (water hammer) was adopted by a software named Bentley HAMMER through two scenarios (with and without control device). An operational control measure was proposed to be adopted by a surge tank for minimizing the probability of the occurrence of the water hammer, also to protect the dam from this problem. The results showed that using of surge tank protects the pipe network effectively from the effect of water hammer. Distribution profiles of velocities and pressures on the pipeline indicate that the water hammer on the pipeline was clearly reflected.
We evaluate the polymer, surfactant and alkaline flooding performance in porous media by using an in-house innovative experimental setup. This, to reach an optimum experimental evaluation in an attempt to avoid repeated experimental failures reported in the literature. The workflow presented help us to understand the recorded data with high reliability and accuracy. Moreover, allow working at high temperatures and high salinities in order to mimic reservoir conditions. The evaluation undertaken in this paper comprises four main steps: 1) Fluids preparation and optimization, beginning with an extensive rheological evaluation to define the optimum concentration/composition of the fluids. 2) Calibration of pressure sensors and pumps, and detailed determination of the system's dead volume. 3) Routine core analysis was performed, which included measuring porosity, permeability and pore volume. 4) Spontaneous imbibition experiments, secondary and tertiary mode cEOR flooding experiments. The core flooding experiments were performed at a constant flow rate of 0.15ml/min (equivalent to the field conditions of 1ft/day), then followed by a bump rate after Sor is reached. The constructed setup proved to be beneficial on reducing the experimental failures by showing data reproducibility and precision. Small diameter tubings of 1/16″ minimized the dead volumes and core face differential pressure measurement allowed high accuracy at any injection rate. At elevated temperatures (50°C) polymer flooding in secondary mode showed 2% higher recovery compared to tertiary mode. Similar difference was observed at the ambient temperature. For the conditions evaluated in this work, HPAM polymer showed higher recoveries than those of Bio-polymer at higher temperatures. However, lower recoveries from HPAM were observed at lower temperatures. In terms of surfactant flooding experiments the observed performance is significantly better in secondary compared to tertiary mode, as well as facing significant production of emulsion from suboptimal surfactant solutions. Thoroughly examining these differences in recoveries, two key factors were considered to be of critical interest: initial oil saturation and mobility ratio. Moreover, CT scan imaging allowed assessing capillary end effects during oil saturation. A detailed comparison between dry and saturated core images was performed to insure no capillary end effects existed. Finally, a developed mathematical simulation model permitted to quality check the work and create a benchmark for further evaluations. The workflow presented in this paper helps to close the gaps often discussed in the literature with regards to flooding experimental failures at core plug scale. Thus, it can help fellow researchers to optimize their workflow and enhance the final results to aid in fluid evaluation and assessing the optimum cEOR process.
A novel reactive smart tracer method, termed the kinetic interface-sensitive (KIS) tracer test, has been demonstrated in laboratory column experiments to enable measurement of the specific capillary-associated fluid–fluid interfacial area in dynamic two-phase flow displacement processes in porous media. Development of the tracer method towards effective application in real field conditions requires investigation of the influence of the porous media heterogeneity on the front size and the specific interfacial area, and, consequently, in how far a kinetic interface-sensitive tracer experiment, and the corresponding breakthrough curves, are affected. This study employs a two-dimensional Darcy-scale two-phase flow reactive transport model to investigate numerically the KIS tracer transport in heterogeneous porous media. Simulations were carried out for the primary drainage process in a domain formed of fine and coarse porous media. Various heterogeneity patterns, having different numbers of inclusions and different geometrical distributions, were studied. It is shown that the shape of the breakthrough curves can be used as an indicator for quantifying the displacement front roughness, the specific interfacial area in the domain, and the domain heterogeneity, e.g., the existence of preferential flow pathways inside the porous media. The results indicate that when the displacement front roughness is small, the concentration breakthrough curves exhibit a linear increase. The slopes of the breakthrough curves linearly depend on the fraction of the bulk volume occupied by the low-permeability sand inclusions. The volume-averaged specific interfacial area and the size of the transition zone can be determined from the slopes of the breakthrough curves.
<p>The newly developed kinetic interface sensitive (KIS) tracers have been the focus of research in the past decade, as a new method to determine the mobile interfacial area between immiscible fluids in porous media. An accurate and reliable interfacial area determination is crucial to several industrial applications and the geoscientific research.</p><p>In this work we investigate the relationship between the concentration breakthrough curves of the KIS tracer, consequently the specific interfacial area and the evolution of the mobile non-wetting-phase front.</p><p>Up to now, such laboratory experiments have been conducted only in columns, quasi-one-dimensional systems. In this study we consider two-dimensional domains filled with porous material where immiscible displacement of water by oil takes place. The presence of heterogenous inclusions leads to perturbations in the fluid interface and causes fingers. By means of numerical modelling we investigate these effects and the results will help as a basis in the design of a new two-dimensional flume setup.</p><p>An analysis is performed for different viscosity ratios, capillary numbers corresponding to different capillary pressure-saturation relationships, injection rates and geometrical heterogeneity. We found that the presence of higher or lower permeability inclusions have a significant but clearly distinct impact on the destruction and/or production of the fluid-fluid interfacial area. Lower permeability inclusions increase the overall area of the front, compared to a decrease in the overall area for higher permeability inclusions. By increasing the interfacial area an increase of the reactive tracer concentration is observed. The mobile interfacial area is evaluated at the front of the saturation profile by using a cut-off value from the saturation profile, and then the area of the mobile concentration of the reactive tracer is calculated.</p>
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