Hasil untuk "Petroleum refining. Petroleum products"

Liu Wencai, He Yadong, Tao Kexu et al.

To improve the separation efficiency of the multi-channel gas-liquid cyclone separator， the RNG <italic>k</italic>-<italic>ε</italic> and DPM models in ANSYS Fluent software were used to conduct numerical simulation on the gas-liquid distribution characteristics in it. The influence of structural parameters （number of channels， baffle height， channel width distribution）， droplet size and flow parameters on its separation performance and pressure drop were studied. Meanwhile， the reliability of numerical simulation was verified by comparing with test data. The study results show that droplets scarcely enter the channel close to the central core pipe in the separator， and channels 2 and 3 serve as the main separation sites in the separator. On the basis of the baffle height designed at a spiral ascent angle of 15° for the airflow， further increasing the baffle height has little effect on the separator's efficiency and pressure drop. The separation efficiency of T6 distribution mode that increases the width of the outermost channel and reduces the width of the inner side channel is the highest. As the number of channels increases， the separation efficiency of the separator for small sizes of droplets increases and the pressure drop decreases. The study results provide a theoretical basis for the design and structural improvement of multi-channel gas-liquid cyclone separators.

CAO Hui, ZHANG Guoqing, XU Li, LI Zhexiang, WANG Haicheng, ZHAO Changyang, FEI Ying

In recent years, basement gas reservoirs in Qaidam Basin have demonstrated significant potential for exploration and development. The Kun 2 block in Kunteyi gasfield, as an ultra-deep basement gas reservoir, poses significant challenges for reservoir prediction and favorable area selection due to its complex internal geology, strong heterogeneity, and dual-porosity characteristics of fractures and dissolution pores. By integrating geological, logging, seismic, and production data, this study developed an innovative integrated method combining “well-seismic integration, static-dynamic fusion, and multi-attribute synergy” to systematically characterize reservoir characteristics and predict natural gas accumulation zones, aiming to reveal the spatial distribution of ultra-deep basement reservoirs and provide guidance for the optimization of well placement. The results showed that: (1) The basement reservoirs in the Kun 2 block primarily consisted of granitic gneiss, with storage spaces characterized by a dual-porosity system of fractures and dissolution pores. The fractures exhibited a network-like development and were distributed in NE-SW trending bands in the plane view. Lateral heterogeneity was significant. The fracture densities ranged from 3 to 10 m-1, the average fracture porosity was about 0.015%, and the matrix porosity ranged from 1.8% to 6.8%. Overall, this demonstrated tight and low-permeability characteristics. (2) The development of dissolution pores was fault-controlled, primarily distributed along Kun 1, North Kun 2, and North Kun 101 faults. These faults formed fracture-pore coupled reservoirs. The interval 100-300 m below the top of the basement was a concentrated development zone, with the maximum reservoir thickness reaching up to 200 m. (3) The innovative integration of maximum likelihood attributes and structure tensor-acoustic impedance inversion technologies achieved high-precision characterization of the spatial distribution of fractures and dissolution pores. The prediction of maximum likelihood attributes revealed that high-angle fractures were mainly located on the upthrown side of faults, exhibiting an 85% consistency rate with imaging logging results. Additionally, the structure tensor-acoustic impedance inversion revealed that zones of dissolution pore development aligned closely with fault orientations, thereby validating the controlling mechanism of fault activity on dissolution process. (4) Based on reservoir classification and evaluation criteria, along with seismic prediction and dynamic production data, this study proposed a reservoir development model of “fault-controlled fractures, fracture-controlled pores” for the first time, indicating structurally high positions on upthrown side as the core zones of natural gas accumulation. Five favorable areas for natural gas accumulation were selected, including four on the upthrown side and one on the downthrown side. Among them, the NE-SW strip zones on both sides of the North Kun 2 Fault were identified as the optimal target areas.

Farshad Mostakhdeminhosseini, Yousef Rafiei

Abstract To avoid or mitigate the unwanted water and gas content, inflow control devices (ICDs) are designed and installed in the well to disturb the water and gas breakthrough which are trying to overtake the oil inflow, water and gas coning and sand production. Smart wells with permanent downhole valves such as ICDs are used to balance production and injection in wells. A paramount issue regarding using downhole control devices is determining the required cross-sectional area of them for control of the imposed pressure drop across the device to stabilize the fluid flow. Current methods for calculating the opening size of the ICDs are mainly based on sensitivity analysis of the ICD flow area or optimization algorithms coupled with simulation models. Although these approaches are quite effective in oil field cases, they tend to be time-consuming and require demanding system models. This paper presents a fast analytical method to determine the ICD flow area validated by a genetic algorithm (GA). Analytically, a closed-form expression is introduced by manipulating Darcy’s law applicable to multi-layer injection wells with different layer properties to balance the injection profile in the reservoir pay zone, based on equalizing injected front velocity in layers with different permeability. Considering various scenarios of analytical technique, GA optimization, and sensitivity analysis scenarios for ICD cross-sectional area determination, results for oil recovery, water production, water breakthrough time, and net present value (NPV) are discussed and compared. NPV values obtained by both analytical and GA approaches are virtually identical and greater than those of other scenarios. Compared to the base field case, the analytical method improved the oil recovery by almost 1%, reduced water production by almost 91%, and synchronized the water breakthrough time of high- and low-permeability layers (from a ratio of 1.76–1.06). The proposed analytical solution proved to be capable of providing desirable results with only one reservoir simulation run in contrast to GA and sensitivity analysis scenarios which require iterative simulation runs. The proposed analytical solution outperformed the GA as it is less computationally demanding in addition to its success in case of lowering water production for the field data. The findings of this study can help for a better understanding of the situation where water injection into the oil reservoir is problematic as the layers present different permeabilities which can induce problems such as early water breakthrough from the more permeable layer and hinder the success of the water injection process. Using ICDs and a faster and more accurate approach to calculate its cross-sectional area such as the analytical method that was used in this study can greatly increase the success rate of water injection in case of oil recovery and lower the amount of the produced water.

ZHANG Lisha, ZOU Pinguo, ZHU Miaomiao et al.

In order to solve the problems of low success rate and large interpretation error of two-flow rate well test in low permeability reservoir, this paper starts from the testing principle and interpretation principle of two-flow rate well test technology in low permeability reservoir. Based on the geological characteristics and production characteristics of low permeability reservoir, the field test, bottom hole pressure conversion and formation parameter calculation are emphatically analyzed, the main problems and influencing factors in two-flow rate well test, bottom hole pressure conversion and formation parameter calculation in low permeability reservoir are analyzed in detail. This paper puts forward the improvement measures and carries out a lot of practices on the spot, the field practice shows that the improved measures can effectively improve the test success rate and interpretation coincidence rate of the two-flow rate well test in low permeability reservoirs, and contribute to the popularization and application of this technology, to provide more reliable data support for oilfield production and measure adjustment.

Changgui Jia, Bo Xiao, Lijun You et al.

Through the stimulation method of large-scale hydraulic fracturing, the spontaneous imbibition capacity of the water phase in the shale reservoir has great influence on the effect of stimulation. Generally, the lacustrine shale has the characteristics of high clay minerals content, strong expansibility, development of nanopores and micro-pores, and underdevelopment of fractures, which leads to the unclear behavior of spontaneous imbibition of aqueous phase. The lacustrine shale of Da'anzhai Member and marine shale of Longmaxi Formation in Sichuan Basin were selected to prepare both the shale matrix sample and fractured shale sample, and the spontaneous imbibition experiment of simulated formation water was carried out. By means of an XRD test, SEM observation, nuclear magnetic resonance test and linear expansion rate test, the mineral composition, the structure of pores and fractures, the capacity of hydration and expansion of both lacustrine and marine shale are compared and analyzed. The results show that the average spontaneous imbibition rate of lacustrine shale is 60.8% higher than that of marine shale within the initial 12 hours of imbibition. The lacustrine shale has faster imbibition rate than the marine shale in the initial stage of spontaneous imbibition. However, the lacustrine shale has underdeveloped pores and fractures, as well as poor connectivity of pores. Besides, the strong hydration and expansion of clay minerals can easily lead to dispersion and migration of clay minerals on the fracture surface, which will plug up the seepage channels, resulting in poor capacity of spontaneous imbibition. The spontaneous imbibition rate in the middle and late stage of Lacustrine shale is obviously lower than that of the marine shale. The overall spontaneous imbibition rate ability of the lacustrine shale is less than that of the marine shale. According to the characteristics of water imbibition of lacustrine shale, considering the dual effects of hydration expansion of clay minerals on the effective reconstructed volume, the microfractures can be initiated and extended by fully utilizing the hydration of shale. Acidification treatment, oxidation treatment or high temperature treatment can be used to expand pore space, enhance water phase imbibition capacity and improve multi-scale mass transfer capacity of the lacustrine shale.

Oluwasanmi Olabode, Pelumi Adewunmi, Odera Uzodinma et al.

Gas cap blow down strategy is normally deployed for Ultra-thin oil rim reservoirs with huge gas caps due to extremely high gas oil ratios from wells in such reservoirs. The current state leads to loss of production from the oil reserves due to high initial reservoir pressure thus, reducing its net present value. Data on important factors essential to the productivity of oil rim reservoirs are used to build a heterogeneous ultra-thin reservoir with a time step of 10,000 days using the Eclipse software and its embedded correlations. The reservoir is subjected to a gas cap blowdown via a gas well, then an oil well is initiated into the model at onset and after time periods of 2000 days, 4000 days, 6000 days and 8000 days to estimate the oil recovery. It is expected that due to the large nature of the gas cap, pressure decline will be drastic and leading to a low oil recovery, hence the injection of water and gas at different rates at the periods indicated. The results indicate an oil recovery of 4.3% during gas cap blow down and 10.34% at 6000 days. Peak oil recoveries of 12.64% and 10.80% are estimated under 30,000 Mscf/day at 4000 days and 1000 stb/day at 6000 days respectively. This shows an incremental oil recovery of 8.34% and 6.5% over that recorded during gas cap blow down. The results also indicate that the gas production at those periods was not greatly affected with an estimated increment of 257 Bscf recorded during 30,000 Mscf/day at 4000 days. All secondary injection schemes at the respective time steps had positive impact on the overall oil recoveries. It is recommended that extra production and injection wells be drilled, enhanced oil recovery options and injection patterns be considered to further increase oil recovery.

Yang Ge, Qingping Li, Xin Lv et al.

To facilitate the recovery of natural gas hydrate (NGH) deposits in the South China Sea, we have designed and developed the world's largest publicly reported experimental simulator for NGH recovery. This system can also be used to perform CO2 capture and sequestration experiments and to simulate NGH recovery using CH4/CO2 replacement. This system was used to prepare a shallow gas and hydrate reservoir, to simulate NGH recovery via depressurization with a horizontal well. A set of experimental procedures and data analysis methods were prepared for this system. By analyzing the measurements taken by each probe, we determined the temperature, pressure, and acoustic parameter trends that accompany NGH recovery. The results demonstrate that the temperature fields, pressure fields, acoustic characteristics, and electrical impedances of an NGH recovery experiment can be precisely monitored in real time using the aforementioned experimental system. Furthermore, fluid production rates can be calculated at a high level of precision. It was concluded that (1) the optimal production pressure differential ranges from 0.8 to 1.0 MPa, and the wellbore will clog if the pressure differential reaches 1.2 MPa; and (2) during NGH decomposition, strong heterogeneities will arise in the surrounding temperature and pressure fields, which will affect the shallow gas stratum.

Mohammad A. Abdelwahhab, Nabil A. Abdelhafez, Ahmed M. Embabi

Steeply dipping prograding fan deltas possess high reservoir quality facies that could be excellent targets while exploring for hydrocarbons. Due to their complex stacking nature, and limited examples, delineating their architectural elements is still challenging. In this paper we mainly performed sedimentary facies analysis; applying various disciplines e.g. sequence stratigraphy, seismic stratigraphy, GR-log motifs, and seismic waveform segmentation; so as to adequately depict the reservoir heterogeneity and quality of the Paleozoic Nubia clastics in West Esh El Mallaha Concession (southwest Gulf of Suez rift). Organic maturity prediction, to confirm the hydrocarbon charging from source units to reservoir intervals, was also of most importance in this study. Accordingly, 1D basin model was established to define the past geologic events; subsidence, and thermal maturity; and their controls on sedimentary basin evolution and associated petroleum potential. We utilized several key-information scales; e.g. wireline logs, and seismic profiles. Linking different disciplines applied in this study points to a successful integrated reservoir characterization workflow capable of unfolding ancient environments and the associated hydrocarbon potential. The results show that Nubia Formation was built during the lowstand−transgressive phase of a 3rd order depositional sequence. It encompasses fluvio-lacustrine system with eight sedimentary facies associations; form source to sink. Fluvial channels and mouth bars, settled in subaerial and subaqueous settings respectively, represent the most significant reservoir facies in the area. Given best hydrocarbon-reservoir quality, the deltaic mouth bars ought to attract attention of further oilfield development plans and be considered while investigating similar settings.

Caineng ZOU, Feng MA, Songqi PAN et al.

Energy is the basis of human development and the impetus of society progress. There are three sources of energy: energy of celestial body outside the Earth, the Earth energy and energy of interaction between the Earth and other celestial bodies. Meanwhile, there are three scales of co-evolution: the evolution of the Sun-Earth-Moon system on an ultra-long time scale has provided energy sources and extra-terrestrial environmental conditions for the formation of the Earth system; the evolution of the Earth system on a long time scale has provided the material preconditions such as energy resources and suitable sphere environment for life birth and the human development; on a short time scale, the development of human civilization makes the human circle break through the Earth system, expanding the extraterrestrial civilization. With the co-evolution, there are three processes in the carbon cycle: inorganic carbon cycle, short-term organic carbon cycle and long-term organic carbon cycle, which records human immoderate utilization of fossil energy and global sphere reforming activities, breaking the natural balance and closed-loop path of the carbon cycle of the Earth, causing the increase of greenhouse gases and global climate change, affecting human happiness and development. The energy transition is inevitable, and carbon neutrality must be realized. Building the green energy community is a fundamental measure to create the new energy system under carbon neutrality target. China is speeding up its energy revolution and developing a powerful energy nation. It is necessary to secure the cornerstone of the supply of fossil energy and forge a strong growing pole for green and sustainable development of new energy. China energy production and consumption structure will make a revolutionary transformation from the type of fossil energy domination to the type of new energy domination, depending on a high-level self-reliance of science and technology and a high-quality green energy system of cleaning, low-carbon, safety, efficiency and independence. Energy development has three major trends: low-carbon fossil energy, large-scale new energy and intelligent energy system, relying on the green innovation, contributing the green energy and constructing the green homeland.

Junfei Ma, Linzhou Zhang, Xiu Chen et al.

Abstract Heavy oil is treated as an undesirable raw material in traditional refining markets because of its low yield. However, its rich natural aromatic structure and heteroatomic compounds make it possible to be a precursor to large-scale production of carbon materials. Using heavy oil and three SDA products as precursors, we synthesized highly fluorescent multi-color carbon dots (CDs) by hydrothermal method, which can precisely control the photoluminescence wavelength in the range of 350−650 nm. The synthesized carbon dots have the advantages of good long-term stability and stability under extreme pH conditions and low price. Importantly, the carbon dots synthesized with asphalt as the precursor have the highest fluorescence quantum yield. X-ray photoelectron spectroscopy (XPS) is used to elucidate the effects of different precursor on emission color change and photoluminescence quantum yield (PLQY), thus providing a controlled tuning of the system for the functionalization of CDs. And we further used the CDs in macrophage labeling. This pathway gives a reliable and repeatable industry possibility and may boost the applications of CDs into reality.

Zhang Pengyu, Guo Dengming, Tu Xueyang et al.

In order to solve the problems such as high labor intensity at the time of make up, break out and transfer of tubing as well as the nonsynchronous tubing transfer speed and elevator speed, a folding tubing transfer device was developed. The device carries out tubing transfer by hydraulically driven travelling block, the speed for the travelling block to transfer the tubing changes with the change of falling and rising speed of the travelling elevator, and the speed control of the travelling block is realized by controlling the hydraulic oil displacement of the manually operated reversing valve of the hydraulic motor, which meets the requirements for the field operator to control the speed of running and pulling tubing. Field application results show that the tubing transfer device is convenient for loading and unloading, stable and reliable in operation, and accurate in tubing alignment; worked in with hydraulic elevator, the average speed of tubing make up/break out is 45 per hour, and 50 per hour maximally, which alleviates the labor intensity of workers, significantly improves the workover operation efficiency, and obviously improves the safety performance. The research results provide reference for users, designers and managers in related fields.

Chansu Lim, Jongsu Lee

Abstract This study investigated the efficiency of the oil refining industry using the two-stage method of Markowitz portfolio optimization theory and panel data analysis of about 30 OECD countries from 2005 to 2016, which is a new methodology for measuring the efficiency of the oil industry. The oil refining industry's efficiency is derived from the prices of petroleum products (Naphtha, Gasoline, Kerosene, Diesel, and Fuel Oil) using the portfolio theory. The panel data was constructed using the following dependent variables, the crude oil production efficiency, energy consumption, renewable energy consumption, and R&D investment. Using the panel data analysis, empirical analyzes are conducted on how the efficiency of the oil refining industry is affected by explanatory variables. The results show that crude oil production and energy use in OECD countries have a negative effect on the efficiency of the oil refining industry, and consumption of renewable energy and R&D investment have a positive effect. Contrary to conventional perception, the petroleum industry can coexist with the renewable energy industry for sustainable development.

Alexander Ogbamikhumi, Nosa Samuel Igbinigie

Abstract Direct hydrocarbon indicator (DHI) expressions observed on seismic could arise due to various geological conditions. Such expression could lead to misinterpretation as hydrocarbon presence if not properly analyzed. This study employs rock physics attributes analysis to evaluate an identified prospect in the undrilled area of the studied reservoir. Prospect identification was actualized by analyzing structural and amplitude maps of the reservoir, which revealed a possible roll over anticline at both the exploited and prospective zone, with a very good amplitude support that conforms to structure. Well-based cross-plot analysis adopted four cross-plot techniques for feasibility study to test the applicability of rock physics for prospect evaluation in the field; Lambda-Rho versus Lambda-Rho/Mu-Rho ratio; Mu-Rho versus Lambda-Rho; and Poisson Ratio versus P-impedance. The result presented Poisson ratio, Lambda-Rho and Lambda/Mu-Rho ratio as good fluid indicator and Mu-Rho as a viable lithology indicator. As such, they were selected for seismic-based attribute and cross-plot analysis to validate the identified prospect. The results from seismic-based analysis showed consistency in the expression of the analyzed attribute at both the exploited and prospective zone. The seismic-based cross-plot analysis result was similar to the well-based analysis and was able to confirm that the observed amplitude expression in the exploited zone is an indication of hydrocarbon-bearing sand.

Ehsan Zareie shirazani, Taraneh Jafari Behbahani

Gas injection process is a very important technology in enhanced oil recovery. Minimum miscible pressure is one of the key parameters in gas injection processes. Various experimental methods such as slim tube are used to measure MMP. These methods are costly and time consuming. Recently computational methods are used in order to achieve a cost-effective and reliable technique to evaluate MMP. In this work, a new methodology has been proposed for determination of MMP using the minimum tie line length method. A real mixing cell model was developed to estimate the MMP, MME and key tie lines. This method is simple, robust, and faster than conventional one-dimensional simulation of slim tube. The new mixing cells method can accurately determine the whole key tie lines to a shift, regardless of the number of injection gas and reservoir fluid components. Unlike other methods of mixing cells, this method automatically corrects dispersion by additional contacts to achieve the low variation domain of tie line slope. Also, the determination and implementation of the minimum miscibility enrichment are investigated. Keywords: Minimum miscible pressure, Minimum miscibility enrichment, Multiple mixing cells method, Enhanced oil recovery, Minimum tie line length method

Siavash Ashoori, Mehdi Sharifi, Mohammad Masoumi et al.

Asphaltene precipitation and deposition are drastic issues in the petroleum industry. Monitoring the asphaltene stability in crude oil is still a serious problem and has been subject of many studies. To investigate crude oil stability by saturate, aromatic, resin and asphaltene (SARA) analysis seven types of crudes with different components were used. The applied methods for SARA quantification are IP-143 and ASTM D893-69 and the colloidal instability index (CII) is computed from the SARA values as well. In comparison between CII results, the values of oil compositions demonstrated that the stability of asphaltenes in crude oils is a phenomenon that is related to all these components and it cannot be associated only with one of them, individually.

Lei Zhen, Liao Heng, Dong Feifei et al.

In order to study the dynamic response of the long-distance suspended pipeline under the action of seismic load, the general finite element software ABAQUS has been used to conduct numerical simulation. The stress and deformation characteristics of the suspended pipeline under the distribution have been analyzed. The effects of the parameters, like the suspension length, the soil parameters, the pipe size and the pipe wall thickness, on the dynamic response of the suspended pipe have been investigated. The results show that the pipe wall thickness, the suspension length, the soil parameters and the pipe diameter have a great influence on the seismic response of the buried pipeline, and the pipe diameter has the greatest influence. In a certain diameter range, the peak stress and displacement gradually decrease with the pipe diameter. But the peak stress would increase with the pipe diameter when the critical value is reached. The study results could provide references for the design, safety maintenance and scientific management of long distance suspended pipeline.

Yang LI, Jiagen HOU, Yongqiang LI

Taking the Ordovician fracture-cavity carbonate reservoir of Tahe oilfield, Tarim Basin as an example, the fracture-cavity reservoir has been classified according to the type and size of reservoir space, and a 3-D geological model of fracture-cavity reservoirs was built according to their types and classes. Based on core, drilling, logging and seismic data, the fracture-cavity reservoir was divided into four types, namely cave, dissolved pore, fracture and Matrix block types, in which the cave was subdivided into two subtypes, large cave and small cave; and the fracture was subdivided into four subtypes, large scale fracture, meso-scale fracture, small scale fracture and microfracture. The large cave model was established using deterministic method via seismic truncation and pattern modification. The small cave model was built using the method of multiple-point geostatistical simulation with large cave model as the training image. The dissolved pore model was built using sequential Gaussian simulation. The large scale fracture model was established using the deterministic method of manual interpretation, meso-scale fracture model was built using deterministic method of ant tracking, the small scale fracture model was built using stochastic object-based modeling. The micro-fracture and Matrix block have no discrete distribution model established because of their poor storage quality. Then the different types of reservoir space models were merged into one model to get the discrete distribution model of typical fracture-cavity unit. The application in Tahe blocks 6 and 7 showed that this classified hierarchical modeling improved the reservoir model precision, guided the water-flooding effectively and advanced the development efficiency. Key words: fracture-cavity reservoir, reservoir type, classified hierarchical modeling, Tahe oilfield, Ordovician

宋晓东

现有的旋转防喷器与小钻具配合密封及井口防喷器组不匹配，难以满足小井眼氮气钻井要求，为此，研制了DQX-Ⅳ型小尺寸旋转防喷器。DQX-Ⅳ型旋转防喷器的整体结构设计充分考虑了现场施工及维护保养要求，具有体积小、安装快捷、动作灵活、维护保养方便等特点，为小钻具及小钻机欠平衡钻井提供了井口保障，为拓展欠平衡钻井应用领域提供了技术支持。试验结果表明，该旋转防喷器达到了现场使用要求，能够满足小井眼氮气钻井的需要。

Masoumeh Tajmiri, Seyed Mousa Mousavi, Mohammad Reza Ehsani et al.

Efforts to enhance oil recovery through wettability alteration by nanoparticles have been attracted in recent years. However, many basic questions have been ambiguous up until now. Nanoparticles penetrate into pore volume of porous media, stick on the core surface, and by creating homogeneous water-wet area, cause to alter wettability. This work introduces the new concept of adding ZnO nanoparticles by an experimental work on wettability alteration and oil recovery through spontaneous imbibition mechanism. Laboratory tests were conducted in two experimental steps on four cylindrical core samples (three sandstones and one carbonate) taken from a real Iranian heavy oil reservoir in Amott cell. In the first step, the core samples were saturated by crude oil. Next, the core samples were flooded with nanoparticles and saturated by crude oil for about two weeks. Then, the core samples were immersed in distilled water and the amount of recovery was monitored during 30 days for both steps. The experimental results showed that oil recovery for three sandstone cores changed from 20.74, 4.3, and 3.5% of original oil in place (OOIP) in the absence of nanoparticles to 36.2, 17.57, and 20.68% of OOIP when nanoparticles were added respectively. Moreover, for the carbonate core, the recovery changed from zero to 8.89% of OOIP by adding nanoparticles. By the investigation of relative permeability curves, it was found that by adding ZnO nanoparticles, the crossover-point of curves shifted to the right for both sandstone and carbonate cores, which meant wettability was altered to water- wet. This study, for the first time, illustrated the remarkable role of ZnO nanoparticles in wettability alteration toward more water-wet for both sandstone and carbonate cores and enhancing oil recovery.