مجله پژوهش نفت
پیاپی 115 (بهمن و اسفند 1399)

As oil fields approach to the end of the primary production phase, the new technologies should be employed to increase the recovery of hydrocarbons. In recent decades, nanofluid has been proposed as an efficient, and environmentally friendly approaches for EOR purpose. The target of this study is to investigate the effect of silica nanoparticle on the wettability alteration of the carbonate rock. In this study, four different concentrations of silica nanoparticle were used (0.01, 0.02, 0.05, and 0.1 wt.%) in low salinity seawater (1000 ppm of positive ions). The stability of nano particle in brine is one of the challenge while using for EOR. In this study the stability of nano fluid was achieved without using any surfactant. The Spontaneous imbibition experiments, and contact angle measurements were carried out at 75 °C to check the performance of nano fluids in wettability alteration of carbonate rock. The results showed that the silica nanoparticle has a significant effect on the oil recovery from carbonate rock. The diluted sea water (1000 ppm) without nano particle resulted to the oil recovery of 10.45% whereas nano fluid with concentration of  0.01, 0.02, and 0.05 wt.%  resulted to the oil recovery of 11.5%, 10.83%, and 22.16% , respectively. The contact angle results also confirmed that the silica nanoparticle has a positive effect on the wettability alteration of the carbonate rock surface toward water wetness. The permeability measurement after and before spontaneous imbibition tests showed that the pores were not blocked due to nano particle precipitation. The impact of initial water in the rock was investigated on the performance of wettability alteration while using nano fluid. The results depicted that the presence of initial water in the carbonate rock adversely affect the oil production.

This paper presents an integrated study using the combination of well test analysis and well log interpretation to characterize the reservoir behaviour of a gas-condensate carbonate reservoir. The results show that the integrated reservoir study using field data including petrophysical and production logging, wireline formation tester and well test analysis is extremely beneficial in achieving more certain reservoir findings and clarifying some uncertainties such as heterogeneous reservoir behaviour and boundary dominated flow effects. The integrated study is also used to evaluate the performance of an acid treatment job conducted on the same well/reservoir. This manuscript provides an integrated approach for reservoir characterization and study of the complex hydrocarbon reservoirs.

Decrease in the amount of oil content and total petroleum hydrocarbons (TPH) in the wastewater of petrochemical plants and oil refinery to environmental discharge standard level has been one of the most critical challenges in recent years, requiring new scientific ideas and techniques. In this study, the superhydrophilic ZnO surface was fabricated using a facile and inexpensive coating method on the stainless steel mesh. The prepared surface was characterized using the FESEM, XRD and Raman analyses. The wettability property of the zinc oxide surface was evaluated via the water contact angle and contact angle hysteresis measurements. The FESEM micrograph results show that the coated hierarchical ZnO structure includes two layers of vertically aligned nanorods bottom arrays with a diameter of less than 50 nm and flower-like microstructures at the top composed of ZnO needles with the tip diameter approximately 100 nm. The fabricated surface exhibits superhydrophilc-superoleophobic property with the water contact angle ~ 0° in the air and 161 ± 3° underwater, respectively. This surface also displays excellent performance to separate hydrocarbonic contaminations from wastewater of Shahid Hasheminejad Gas Processing Company with the separation efficiency and permeate water flux of more than 99.9% and 5800 L m-2 h-1, respectively. The average total oil concentration in the effluent sample was significantly reduced from 5000 mg.L-1 to 17.3 mg.L-1. Moreover, the TPH concentration was decreased to 15.5 ppm in the treated effluent. These results show out the great potential of the superhydrophilic ZnO surface for wastewater treatment and offshore oil spills.

In this study, the effect of anionic and cationic surfactants on enhanced oil recovery was investigated by considering the wettability alteration and interfacial tension. The alpha olefin sulfonate (AOS) and cetrimonium bromide (CTAB) were considered as anionic and cationic surfactants respectively. Firstly, the stability of chemical solutions was evaluated by zeta potential test and so these solutions were used to IFT, wettability, coreflooding, and surfactant adsorption tests. Also, the surface forces were analyzed to investigate the isoelectric point and surfactant adsorption. The results show that the anionic and cationic surfactants can significantly reduce the interfacial tension. Also, the anionic surfactant alters the reservoir wettability from strongly oil wet (159o) to water wet (37o). Based on the isoelectric point, the anionic surfactant adsorption is higher than that for cationic surfactant adsorption. Consequently, the low salinity sea water which includes cationic surfactant, due to no snap-off phenomena, improved the oil recovery factor up to 19 % compared to sea water injection.

In gas transmission processes, a significant amount of methane gas is transferred to the environment for several reasons, including leakage and pipe breakage, which has a high contribution to greenhouse gas emissions. The global methodology for reducing greenhouse gases has led to a plan to reduce greenhouse gas emissions from gas transmission lines according to international conventions and the national action plan to reduce greenhouse gas emissions. Therefore, the purpose of this study in first was experimentally measurement of methane gas emission due to leakage of blowdown valves from different points of district seven of gas transmission operation and then the prediction of gas emission factors using multilayer perceptron neural network with backpropagation of error and Levenberg-Marquardt algorithm. Accordingly, the effect of operating parameters on the emission factor, including ambient temperature, pipeline pressure, type of valve, condition of the valve (open or close) located before of blowdown, Internal leakage of bypass valve before blowdown, life of blowdown valve, the sound of leakage and concentration of the leakage in the range of 10-10000 ppm were investigated. To find the effective parameters on the emission factor, six various schemes were considered based on different input parameters. The results of prediction of methane emission factors using neural network showed that the scheme with input parameters as ambient temperature, pipeline pressure, age of valve, the sound of leakage and concentration of the leakage shows the best results. Deviation with measurements and coefficient of determination (R squared) of the best scheme among the six schemes are equal to RMSE=0.05047, MSE=0.00255, and R2=0.97853, which they show that this method can be used to predict the methane emission factors in natural gas transmission pipelines.

In this study, the pervaporation method was used for the desulfurization of gasoline. Thiophene was used as a sulfur agent and n-heptane as a representative of hydrocarbon compounds in gasoline. Hybrid membranes were fabricated with active layers composed of polydimethylsiloxane (PDMS) and metal-organic framework UiO-66, together with support layers composed of polyvinylidene fluoride (PVDF). Scanning electron microscopy (SEM), Fourier transform infrared spectrum (FTIR) and X-ray diffraction (XRD) were used to characterize nanoparticles and synthesized membranes. Furthermore, the effect of UiO-66 incorporation on swelling and pervaporation performance of the hybrid membranes was evaluated. The optimal performance was achieved when the weight fraction of UiO-66 to PDMS was 8% with a flux of 10.73 kg.m-2h-1 (increased by 90% compared with the PDMS control membrane) and an enrichment factor of 3.96 (increased by 27% compared with the PDMS control membrane).

Acoustic impedance can be considered as a measure of rock strength to the propagation of waves, which is a product of the density and compressive wave velocity of the rocks. Geophysicists are trying to estimate the acoustic impedance of rock layers from reflective seismic data, called seismic inversion. The difference of acoustic impedance in the common layer of layers reflects the seismic waves. Acoustic impedance is the property of rock itself, and the harder the rocks are, the higher the acoustic impedance is. Seismic inversion can be used as a reliable method for (1) estimating reservoir properties quantitatively and (2) obtaining quantified values of acoustic impedance from seismic data, well-logging data, and interpreted horizons. In general, acoustic impedance has a strong relationship with petrophysical properties such as fracture, saturation and porosity. The purpose of this study was to estimate the initial model of acoustic impedance using different seismic inversion methods to determine reservoir characteristics and compare their results in the Whicher-Range field of Perth Basin, Western Australia. For this purpose, two wells and a seismic section from the field were used. All steps were performed using the Hampson-Russell software. First, the depth-time relationship between well logs and seismic data was corrected. Then, the compatibility of the synthetic seismogram resulting from the seismic wavelet convolution with the series of reflections produced at the well location was investigated with seismic data. Various inversion algorithms including Model-based, Band-limited, Sparse Spike (Linear Programming) and Sparse Spike (Maximum Likelihood) were inspected. The correlation coefficient in all methods shows an acceptable value. Using wavelet extraction and investigation of different inversion algorithms, the model-based method, as the best method with high correlation coefficient and less error among other algorithms, was used for initial modeling. In the interval of 2050 to 2250 milliseconds of the studied section, acoustic impedance decreases significantly, indicating porosity in the reservoir area.

In this study, the equilibrium and kinetic absorption of 1-butanol on activated carbon adsorbent has been studied. Langmuir, Freundlich, and Toth isotherms are fitted on equilibrium data. A quasi-quadratic kinetic model and bifurcation penetration model have been used to model the absorption kinetics. The results have shown that the absorption of 1-butanol on active carbon is predicted by the Freundlich and Toth isotherm models with AARD 6.3% and 5.9% respectively. The pseudo-second kinetic model is well adjusted to experimental kinetic data. Using the biodegradation diffusion model, it has been shown that the intrusive penetration alone cannot predict the kinetics of adsorption, and there is more than one stage in the 1-butanol absorption process. Also, the results of the samilar work showed that the active carbon adsorbent used in this study was two times more absorbent than the zeolite adsorbent used in the references.

Asphaltene deposition in porous media during miscible injection, as an enhanced oil recovery method, results in permeability impairment and thus formation damage. The degree of the permeability reduction due to asphaltene deposition is a function of the asphaltene deposition pattern. In this study, the effects of viscous and gravitational forces on the deposition pattern of asphaltene during miscible displacement of oil in a glass micromodel were studied. Dead oil was dissolved in a toluene/gasoil mixture to prepare model oil. A homogeneous micromodel with the pore and throat sizes of 160 and 80 μm, respectively, was prepared and employed for the miscible displacement of the model oil by normal hexane at the injection flow rate of 0.04 mL/h. The flow rate leads to a very low Reynolds number which is a characteristic of laminar flow in the porous media. To shed light on the contribution of the gravitational force to the deposit amount and deposition pattern, the displacement tests were conducted at the dip angles of 0, 10, and 20 degree in the injection direction. It is found that the deposition mechanism of asphaltene is divided into three main categories of deposition on surface, pore throat blocking, and internal filter formation. The deposition mechanism and thus deposition pattern of asphaltene depend on whether the viscous or diffusion/dispersion force is the dominant force in the porous media. The breakthrough time and thus the oil recovery factor is improved in the tilted displacements. In addition, in comparison to horizontal flow, the deposit amount of the asphaltene is decreased by 70.5 and 82.3% at the dip angles of 10 and 20 degree, respectively. Diffusion/dispersion increases the deposit amount of asphaltene, leading to a harsh damage. However, the viscous force may either strengthen or weaken the asphaltene deposition.

Nowadays, sulfur recovery processes tend to be no longer economic, as well as having various operational problems. They also discharge large amounts of CO2 into the atmosphere. The alternative is to compress and inject acid gas into geological formations with the purpose of enhanced oil recovery and acid gas sequestration for environmental protection. In this review article, after providing the initial definitions in acid gas studies, sour gas sweetening methods and their most prominent operational difficulties have been introduced and compared with each other by us. By completing the sour gas sweetening process, a problematic flow of acid gas is produced. Next, we address the theoretical foundations, the application scope, cost, and operational-economic challenges of different sulfur recovery methods in a try to explain the importance of exhausting the issue of acid gas injection in geological formations from a technical and economic point of view. We also present and discuss the principles of acid gas injection into geological formations, the criteria for selecting a suitable formation for injection, and the trapping mechanisms of acid gas.