Sandstone Formation Research Articles

Evaluating the regional geological characteristics of the St. Peter Sandstone and Everton Formation for CO2 storage in Southern Illinois: A case study on site-specific injection feasibility in Washington County, Illinois

Evaluating the regional geological characteristics of the St. Peter Sandstone and Everton Formation for CO2 storage in Southern Illinois: A case study on site-specific injection feasibility in Washington County, Illinois

Assessing Geothermal Energy Production Potential of Devonian Geothermal Complexes in Lithuania

Lithuania is a Baltic European country which shares borders with Poland, Belarus, Latvia, and Russia and has a geothermal anomaly in the southwestern region. It consists of two main geothermal complexed, i.e., Devonian and Cambrian with a temperature of up to 40 °C (at a depth of 1000 m) and 96 °C (at a depth of 2000 m), respectively. The Devonian complex is composed of an unconsolidated sandstone formation with porosity and permeability in the range of 4–31% and 200 mD–6000 mD, respectively, and these make it a favorable candidate for a low enthalpy geothermal complex because of the high water production rates. This study evaluates the geothermal potential in the Devonian complex of the selected sites for commercial development. The study utilizes the mechanistic modelling approach including uncertainty management to forecast the water production rates and estimate the power generation capacity. Lastly, the study reveals that it is feasible to produce 6 MW to 60 MW of power from the existing vertical wells for a period of 25 years. Furthermore, reactive transport modelling also proves that there is dissolution and precipitation of the minerals near and away from the wellbore, respectively, which impairs the reservoir quality and further concludes that there is an effect of time on re-injection which should be considered to enhance the reservoir quality for future operations. In addition to that, no effect of the re-injection temperature of the produced water is observed.

Wedged between two congeners: will the real Gompholobium nitidum (Fabaceae: Mirbelieae) please stand up?

The most recent review of the genus Gompholobium Sm. (Fabaceae: Mirbelieae), published in 2008, considered Gompholobium nitidum Sol. ex Benth. to exhibit a high degree of variation, ranging from very compact shrubs with linear leaflets, to open shrubs of a taller stature with lanceolate leaflets, through to dense shrubs with oblong leaflets with obtuse-emarginate apices. We use morphological and ddRAD sequencing data to recognise three species from this broad complex, linked with topographic and edaphic complexity in the study area (Laura south to the Atherton Tablelands, north-east Queensland): (1) G. nitidum sens. strict. is a narrowly distributed taxon limited to the white sands of coastal dunes north of Cooktown, with a single disjunct population south of Cooktown; (2) a novel species described here, G. cinctum M.T.Mathieson & C.L.Simmons, has a slightly broader distribution across the skeletal sandy loams of sandstone formations in the Cooktown region; and (3) G. papuanum Merr. & L.M.Perry, previously subsumed into G. nitidum, is reinstated and occurs broadly across north-east Queensland in woodlands from west of Townsville to Cape York, the Torres Strait Islands and into Papua New Guinea.

Studying of high pressure/deep formations based on rock mechanical properties evaluation

Geomechanics plays a significant role in all phases of an oil and gas field’s life cycle, from exploration to production and even beyond field abandonment. It has various applications in the petroleum industry, such as predicting safe mud window and determining the magnitude and direction of in-situ stresses. The objective of this study is to determine the magnitude and orientation of far-field stresses, identify fault types, estimate pore pressure, and evaluate mechanical properties for different formations by constructing a one-dimensional geomechanical model (1D-MEM) for a deep well in the Halfaya oilfield. This study utilizes open-hole log measurements, including density, sonic compression and shear wave velocities, gamma-ray, caliper, and bit size. The results from the model indicate that the Mishrif A, Mishrif B1, Mishrif B2, Mishrif C1, Mishrif C2, Mishrif C3, Mauddud, Nahr Umr B, Ahmadi, and Zubair formations exhibit normal faulting. On the other hand, the Nahr Umr A, Shuaiba, Ratawi, and Yamama formations show strike-slip faulting. The Rumaila formation, based on the magnitudes of the far-field stresses, appears to exhibit reverse faulting. Furthermore, the Yamama formation demonstrates abnormally high pore pressure, while other formations are considered natural pressure formations. In terms of rock properties, shale and sand formations have lower Young's modulus, Poisson's ratio, and UCS, whereas limestone formations have higher values. Moreover, limestone formations exhibit higher friction angles compared to sandstone and shale formations.

Diagenetic controls on the porosity of adigrat sandstone formation in the Dejen-Gohatsion section of the Blue Nile Basin, Central Ethiopia

Diagenetic controls on the porosity of adigrat sandstone formation in the Dejen-Gohatsion section of the Blue Nile Basin, Central Ethiopia

Identification of clay mineral compounds in the Southern Iraqi upper Nahr Umar Formation using SGR logging

Typically, sandstone oil reserves comprise various clay minerals, such as illite, chlorite, and kaolinite. The existence of these clay minerals drastically affected the quality of these reservoirs. This paper attempts to detect clay minerals and environmental deposition of the upper shaly-sand unit (USSU) of the Nahr Umar formation, as it is the main reservoir. It is a portion of an anticline composed of a lower Cretaceous clastic sandstone formation. The kind of environment, clay minerals, and depositional correlation between total organic matter and uranium content were determined using a spectral log of gamma-ray (SGR). According to the SGR log, the primary constituents of USSU are mixed-layer clays, which are illite, kaolinite, and chlorite. The investigated wells in the field's western north have Th/U (thorium/ uranium) ratios ranging from 0.465 to 18.4. Based on the Th/U ratio, the USSU had a mostly shallow marine with continental and marine environment traces. Additionally, a Th/K (thorium /potassium) cross-plot revealed that as kaolinite decreased, illite increased in the formation's southern region.

Delineating Structural Features Related to Hydrothermal Alterations for Possible Mineralization in Share Area, Kwara State Nigeria Using Aeromagnetic Data

Mineral deposits of significant economic value are abundant in the subsurface of Nigeria, presenting a promising alternative to the nations over dependence on petroleum revenues. This study interprets aeromagnetic data from Share, Kwara State, Nigeria, to delineate subsurface structural features associated with hydrothermal zones, which are key indicators for potential mineralization. The methodologies applied upward continuation, analytic signal, tilt derivative, and first vertical derivative (FVD). These offer insights into subsurface geology that can be broadly applied in geophysical exploration and mineral resource management. The results reveal structural trends predominantly in the NE–SW direction, with some NW–SE alignments, indicative of hydrothermal alterations linked to mineral deposits. The analytical signal map identified amplitude values ranging from 0.004 nT/m to 0.073 nT/m, with low and intermediate magnetic intensities linked to sediment-filled basement rocks and possible limestone and sandstone formations. High-gradient anomalies, 1.280 nT/m to 1.374 nT/m, were attributed to geological contacts, fractures, dykes, and hydrothermal vents. Depth estimates from the source parameter imaging map revealed hydrothermal and structural zones at depths ranging from 287.9 m to 1360.7 m, with deeper sources >1202.1 m indicating tectonic activity and mineralization potential. The FVD and Tilt Derivative maps further highlighted faulted zones, shear structures, and intrusive bodies with intensities between 0.031 nT/m and 0.041 nT/m, suggesting active tectonics. High magnetic anomalies in the central, northeastern, and southeastern regions were identified as prime targets for exploration, indicating magnetite-rich bodies, igneous intrusions, and hydrothermal zones. Integrated exploration strategies combining geophysical, geochemical, and structural data are recommended to refine anomaly delineation, prioritize field validation, and enhance mineralization discovery. These findings establish the Share area as a promising site for regional mineral exploration, supporting Nigeria’s diversification efforts toward sustainable resource development.

Diversidade físico-geográfica no semiárido nordestino: unidades de paisagem na Bacia do Rio Bastiões, Ceará (Brasil)

The Brazilian semiarid region is a region with highly diverse landscapes that, due to tectonic controls associated with the action of past climates, gave rise to a complex mosaic of geomorphological forms, making this region one of the most heterogeneous, from a physical-natural point of view, within the Brazilian territory. Understanding and classifying landscape diversity, especially in drylands, is necessary for more effective territorial management and planning. From this perspective, this work aims to identify and understand the landscape units in the Bastiões River Basin (BHRB), in the south of the state of Ceará. This area is inserted in the context of the Chapada do Araripe and the Depressão Sertaneja, therefore located in an area of ​​geological and geomorphological transition, a fact that is reflected in the identified units. In this work, Landscape Units are understood as areas with characteristic relief patterns, differentiated based on their homogeneous physiographic and morphological configuration. Twelve landscape units were identified, some associated with the crystalline basement and others with sedimentary deposits. Among the units inserted in the crystalline geology, the dissected surface in ridges stands out, located in the central area of ​​the basin, and composed of an igneous lithology associated with the Campos Sales-Assaré Pluton. In the sedimentary substrate, the structural summit and the convex top stand out, supported by the fluvial sandstones of the Exu Formation. These units reflect the heterogeneity of the basin and the action of lithostructural, geomorphological and climatic controls on the morphology and dynamics of the landscape, notably distinct in the areas of crystalline and sedimentary basement.

Assessment of Two Crosslinked Polymer Systems Including Hydrolyzed Polyacrylamide and Acrylic Acid-Hydrolyzed Polyacrylamide Co-Polymer for Carbon Dioxide and Formation Water Diversion Through Relative Permeability Reduction in Unconsolidated Sandstone Formation.

One of the most challenging aspects of manipulating the flow of fluids in subsurfaces is to control their flow direction and flow behavior. This can be especially challenging for compressible fluids, such as CO2, and for multiphase flow, including both water and carbon dioxide (CO2). This research studies the ability of two crosslinked polymers, including hydrolyzed polyacrylamide and acrylic acid/hydrolyzed polyacrylamide crosslinked polymers, to reduce the permeability of both CO2 and formation water using different salinities and permeability values and in the presence of crude oil under different injection rates. The result showed that both polymers managed to reduce the permeability of water effectively; however, their CO2 permeability-reduction potential was much lower, with the CO2 permeability reduction being less than 50% of the water reduction potential in the majority of the experiments. This was mainly due to the high flow rate of the CO2 compared to the water, which resulted in significant shearing of the crosslinked polymer. The crosslinked polymers' swelling ratios were impacted differently based on the salinity, with the maximum swelling ratio being 9.8. The HPAM polymer was negatively affected by the presence of crude oil, whereas increasing salinity improved its performance greatly. All in all, both polymers had a higher permeability reduction for the formation water compared to CO2 under all conditions. This research can help improve the applicability of CO2-enhanced oil recovery and CO2 storage in depleted oil reservoirs. The ability of the crosslinked polymers to improve CO2 storage will be a main focus of future research.

An Expanded Wing Crack Model for Fracture and Mechanical Behavior of Sandstone Under Triaxial Compression.

A new model is developed to predict the mechanical behavior of brittle sandstone under triaxial compression. The proposed model aims to determine the normalized critical crack length (Lcr), through which the failure strength (σf) of sandstone can be estimated based on fracture mechanics applied to secondary cracks emanating from pre-existing flaws, while considering the interaction of neighboring cracks. In this study, the wing crack model developed by Ashby and Hallam (1986) was adopted to account for the total stress intensity at the crack tip (KI) as the summation of the stress intensity due to crack initiation and crack interaction. The proposed model is developed by first deriving the Lcr and then setting the crack length equal to the Lcr. Next, the total stress intensity is set equal to the rock fracture toughness in the original equation of KI, resulting in an estimate of the σf. Finally, to evaluate the performance of the proposed model on predicting σf, theoretical results are compared with laboratory data obtained on sandstone formations collected from Wyoming and the published literature. Moreover, the σf predicted by our proposed model is compared with those predicted from other failure criteria from the literature. The comparison shows that the proposed model better predicts the rock failure strength under triaxial compression, based on the lowest RMSE and MAD values of 36.95 and 30.93, respectively.

Pore-scale modelling of particle migration in loose sandstone

During the development of loose sandstone reservoirs, the issue of production decline and bottomhole pressure reduction caused by particle migration is widespread, directly impacting well productivity. Understanding the mechanism of particle migration in sandstone and determining the main factors affecting this process are crucial for improving oilfield development. This study focuses on an offshore oilfield and utilizes real digital core models constructed through CT scanning technology. Numerical simulations of fluid-solid coupling were conducted using Fluent and EDEM software to establish a coupled particle-oil-water flow model. This model was employed to investigate particle blockage modes and the effects of particle size, concentration, and injection rate on particle migration in the reservoir. The results indicate that particle migration primarily occurs in two blockage modes: pinhole blockage and bridging blockage. In sandstone, particle retention rates are primarily controlled by particle size, with larger pore-to-particle size ratios leading to higher retention rates. Particle concentration and injection rate have relatively minor effects on the final retention rate. As for migration distance, particle size significantly influences migration, with larger pore-to-particle size ratios resulting in shorter migration distances. Under low concentration conditions, concentration has a minimal effect on migration distance. However, as the injection rate increases, migration distance also increases. In summary, this study clarifies the particle migration mechanisms and the key factors controlling migration in sandstone formations, providing valuable theoretical support for oilfield development.

DIAGENETIC STUDY BASED ON PETROGRAPHY: IMPLICATIONS FOR SANDSTONE POROSITY OF THE PEUNASU FORMATION, PULAU NASI, ACEH

Diagenetic studies observe the process of changing sedimentary deposits into sedimentary rocks. This study is critical because it relates to the quality of rock porosity, which can be filled by fluid. The analysis of the Peunasu Formation is interesting because previous researchers considered that the Tertiary sedimentary rocks in the Northwest Aceh Basin are equivalent to rock units in the petroleum system in the North Sumatra Basin and Mergui Basin. Meanwhile, studies on the Peunasu Formation, a tertiary sedimentary rock, still need to be completed. Therefore, this study was carried out to determine the characteristics and diagenetic processes in the sandstone of the Peunasu Formation. The method used is petrographic observation, which identifies the composition of rocks along with textures such as grain size, roundness, sorting, grain contact, and porosity. The results are that the Peunasu Formation sandstone is classified as sublitharenite, lithic greywacke, and litharenite. The diagenetic regime is mesogenesis. In the mesogenesis stage, the sandstone of the Peunasu Formation experiences compaction, cementation, and dissolution. The porosity of the Peunasu Formation sandstone, as determined by the percentage of pores, exhibits a range of 0.5% to 16.8%, categorizing it as ranging from negligible to moderate. Compaction reduces the intergranular porosity, while the dissolution of grains contributes to the formation of secondary porosity.

Geotechnical Aspects of Salo Lawo Waterfall in Salopuru Pattappa, Pujananting District, Barru Regency, South Sulawesi

Abstract The Salo Lawo waterfall represents a significant geotourism destination for the community in Pujananting, Barru district. It is of critical importance to identify the geotechnical aspects of this site in order to ensure the safety of visitors and to prevent potential rock mass movements. This research identifies fundamental geotechnical aspects through measuring and observing joints or discontinuities using the scanline method in the field. This is complemented by a kinematic analysis of stereographic projections, which enables the determination of failure modes potential and the classification of rock masses. The Salo Lawo waterfall is formed by sandstone in the Balang Baru formation, which exhibits a medium rock compressive strength. The kinematic analysis indicated that two types of failure could potentially occur on the rock slope wall: wedge sliding (26.29%) and oblique toppling, which is part of direct toppling (23.67%). The potential for planar sliding and flexural toppling was not identified, as indicated by the absence of critical intersections and the presence of only very small critical intersections obtained from stereographic projections. The kinematic analysis conducted in this research project predicts the potential for failure modes to occur at this location. This is considered to be a basic or initial stage in the assessment of the geotechnical aspects of the area. Consequently, further research is required to employ more detailed methods and laboratory testing to estimate the stability of the rock slopes at Salo Lawo waterfall. This will enable the information on geotechnical aspects to become more complete and valuable.

Evaluating karst features and geological fault leakage risks based on geophysical method in Dongzhuang reservoir area, Shaanxi

Leakage along faults, particularly in karst area faults, is a critical concern that can prevent impounding a reservoir. The Laolong Mountain fault in the Dongzhuang Reservoir Project Area in Shaanxi Province, China, is a large fault that may impede the project. To assess whether concentrated leakage can occur along this fault, we used a comprehensive approach involving footrill exploration, an electromagnetic method, optical imaging techniques, water pressure testing, and large-scale groundwater tracer tests. Footrill exploration results revealed that the karst features predominantly comprise karst cavities with some fissures and karst caves. These formations are typically clustered along fractures with a linear joint density of 0.4–1.5 joints/m. The linear karst rate was 0.39 %, and the karst cavities have small diameters of only a few centimeters and depths not exceeding 15 cm. A geophysical exploration indicated that low resistivity values (approximately 200 Ω·m) on the north side of the fault zone's hanging wall, with the lowest values being approximately 100 Ω·m. The fault's footwall was noted to have higher resistivity (approximately 2000 Ω·m). The rock properties on either side of the fault zone differ considerably. The upper plate of the fault (downstream of the river) has high-resistance carbonate rock formations with a well-preserved structure, whereas the lower plate (upstream of the river) comprises low-resistance sandstone and mudstone formations with notable fragmentation at the fault's surface compression zone. Tracer tests indicated an eastward groundwater flow from Zuantian Ridge toward the Jing River in the west. The results suggest that eastward leakage along the Laolong Mountain fault and its influence zone is unlikely upon reservoir impoundment. The geophysical exploration method in this study integrated and cross-validated the footrill exploration, hydrological test, groundwater tracing, optical imaging, and other methods; it can thus serve as a reference for future research.

Gas storage in low-permeability rocks

Low-permeability, dense sandstone formations are ideal for underground gas storage in compressed air energy storage. To examine the gas permeability of fine sandstone under high pressure, a self-developed triaxial high-pressure gas permeameter was used for experiments under varying confining and axial pressures. The study identified unsteady seepage variations and stress dependence in porous media represented by fine sandstone and developed a gas leakage model. Results indicate that the seepage process includes rapid, slow, and cessation stages. Fine sandstone shows excellent storage capacity, with a daily leakage rate of 0.0463%, below required thresholds. This study guides high-pressure gas permeability theories and modeling.

Hydrogen underground storage potential in sandstone formation: A thorough study utilizing surface complexation modelling

This research focuses on the geochemical aspects of hydrogen underground storage, with particular emphasis on surface complexation modelling and its impact on surface potential and surface charge. The primary objective is to develop the first comprehensive surface complexation model specifically tailored for sandstone rocks, emphasizing key minerals such as quartz, kaolinite, and calcite, which are suitable for hydrogen underground storage applications. This model is intended to serve as a benchmark for more research in this field, providing a solid foundation for investigating and improving predictions related to wettability alteration. Additionally, the model has been integrated with hydrogen solubility to accurately capture changes in surface charge. The study identified six brine compositions with various minerals to examine the effect of monovalent and divalent ions. The results showed an increase in solubility with an overall reduction in salinity, and a decrease in divalent ions. The homogeneous surface complexation model demonstrated a neutral surface potential, attributed to an increased mole fraction of positively charged >SiOH+and a decreased in negatively charged >SiO-. Similar trends were observed in kaolinite and calcite minerals. The influence of pH was also explored, revealing a significant impact on the homogeneous quartz case, where an increase in pH shifted the surface potential from neutral to more negative. The heterogeneous cases exhibited less negative behavior as the quartz content increased per case, mainly due the increasing presence of positively charged species such as >SiOH+ and >AlOH+, and the reduction of the negatively charged >AlO-. Increasing the salinity of the solution resulted in less negative surface potential, attributed to the abundance of positive divalent and monovalent ions boosted by increasing salinity, thus the formation of positive surface complexes.

The role of structural compartmentalization in carbon storage site selection in Permian (Rotliegend Group) reservoirs in the Southern North Sea

The Southern North Sea (SNS) gas basin is a key area for CO 2 storage projects in the UK. Many of the now-depleted Permian (Rotliegend) Leman Sandstone Formation fields are being re-evaluated as carbon stores. However, the reservoir is known to be highly faulted, often leading to field compartmentalization. This has historically impacted field development and production, and will challenge suitability for CO 2 storage by limiting site capacity, requiring a high number of injector wells, and increasing capital costs. It is necessary to understand the nature of these pressure compartments - and whether any individual culmination can house sufficient capacity - before devising a carbon storage development programme. The highly compartmentalized Indefatigable (Inde) Field was evaluated as a case study. A static model of the field was constructed using 3D seismic and well log data, and subsequently used to calculate the CO 2 capacity of each of the 12 compartments. Five compartments were found to have capacities larger than 10 Mt, with the large Main Horst found to host 51% of total CO 2 capacity. A sequential filling-and-sealing storage site development plan is suggested based on the evaluation and ranking of these compartments.

Produced water integration in CO2 storage using different injection strategies: The effect of salinity on rock petrophysical, mineralogy, wettability and geomechanical properties

Optimizing CO2 storage efficiency in Deep saline aquifers (DSA) involves improving each storage trapping mechanism, such as structural/stratigraphy, capillary/residual, mineral, and dissolution trapping mechanisms, while maintaining the reservoir integrity for long-term carbon capture and storage (CCS). These enhancements are driven by a series of geochemical reactions that favorably modify petrophysical, mineralogy, wettability, rock geomechanics of the rock, and dissolution of CO2 in aquifer fluid. Three different CO2 injection strategies have been identified and tested for optimizing CO2 storage and efficiency- Continuous CO2 injection (CCI), Water Alternating Gas (WAG), and Simultaneous scCO2-brine Aquifer Injection (SAI). This study investigates the effect of integrating produced water (PW) into WAG and SAI strategies for CO2 storage, emphasizing how the salinity of the injected water affects reservoir properties alterations in sandstone and limestone formations exposed to scCO2. Experimental results show that high salinity levels accelerate mineralogy changes and wettability alteration, particularly in limestone, leading to porosity, permeability, and mechanical strength changes. While the SAI results showed more aggressive and detrimental changes in rock properties, WAG leads to slower reaction rates, a more stable and effective strategy with more gradual alterations in rock properties due to its ability to balance fluid flow and mechanical strength, hence offering greater stability for long-term CO2 storage. Based on these findings, a 20–50 g/L salinity range is recommended to maintain reservoir integrity and reduce the negative impacts of salinity on CO2 storage efficiency and storage. This study provides valuable insights for optimizing CO2 storage in DSAs, enhancing environmental sustainability, and enhancing mineral trapping through more targeted geochemical reactions and lower changes in rock mechanical strength.

Harnessing the power of machine learning for the optimization of CO2 sequestration in saline aquifers: Applied on the tensleep formation at teapot dome in Wyoming

The sequestration of carbon dioxide in deep saline aquifers offers a highly promising approach to mitigate CO2 emissions resulting from the fossil fuels industry. The practicality of this solution is mostly dependent upon the CO2 trapping efficiency, which governs the capacity of the aquifer for CO2 storage. Generally, the compositional reservoir simulation is employed to evaluate the trapping efficiency, but is computationally expensive, particularly when adjusting parameters necessitates hundreds of simulations. In this paper, A machine learning (ML) proxy model was used to address these difficulties for fast evaluation and optimization of the residual and dissolution trapping mechanisms in the Tensleep sandstone formation in the Teapot Dome Field, located in Wyoming, USA. The initial CO2 storage capacity of the aquifer was calculated to be 17.7 thousand tons. In the simulation model, several injection wells were placed in the high porosity regions and CO2 injection was simulated over duration of 10 years, followed by a 90-year post-injection period. The injection rates were optimized to maximize the overall trapping efficiency, which takes into account both residual and solubility indices. In order to construct a dataset for machine learning-based proxy models, the Latin hypercube sampling technique was adopted to generate 100 simulation runs that varied operating constraints: maximum injection rate, maximum injection pressure, and number of injection wells. The Radial Basis Function-Artificial Neural Network (RBF-ANN) was specifically trained to accurately determine the most appropriate injection rates by identifying complex and non-linear correlations within the data. The total CO2 trapping effectiveness by the RBF-ANN model was enhanced from 75% to 83%, accompanied by an insignificant increase in the leakage index from 0.64% to 1.3%. The results indicated that machine learning proxy modeling offers a rapid and accurate approach to optimize the storage of CO2 in saline aquifers. Through the reduction of CO2 emissions, this method significantly improves the viability of large-scale sequestration projects, so making a valuable contribution to climate change mitigation.

Enhancement of surfactant performance via titanium dioxide nanoparticles: implication for oil recovery in sandstone.

The application of titanium dioxide nanoparticles in the petroleum research area has received ample attention in recent years owing to its impact on wettability-altering agents. Further, employing a surfactant injection to improve oil production in sandstone formations on an industrial scale has become an alternative solution, particularly for mature fields. However, the existing literature on the combination of alkyl ethoxy carboxylate (AEC) surfactant with titanium dioxide nanoparticles on the application of enhanced oil recovery in sandstone formations remains underreported. This study explores the impact of combining AEC surfactant with titanium dioxide nanoparticles on recovering trapped oil in sandstone by examining the interfacial tension, contact angle, zeta potential, and core flooding with various concentrations of added titanium dioxide nanoparticles (0, 0.01, 0.025, and 0.05wt%) on AEC surfactant. Although the addition of 0.05 wt% TiO2 to AEC surfactant can significantly reduce the interfacial tension to the lowest value of 5.85 × 10-5mN/m, our results show that the highest oil recovery in Berea sandstone (59.52% recovery factor) is achieved at the concentration of 0.025wt% added TiO2 to AEC surfactant. We find that the stability of TiO2 nanoparticles on AEC surfactant plays a significant role in getting maximum oil recovery. These important findings from this study contribute to improving our understanding on the application of TiO2 combined with AEC surfactant to achieve more efficient and sustainable enhanced oil recovery in sandstone.