Gas Injection Research Articles

Flow and Corrosion Analysis of CO2 Injection Wells: A Case Study of the Changqing Oilfield CCUS Project

In carbon dioxide capture, utilization and storage (CCUS) technology, CO2 flooding and storage is currently the most effective geological storage method and the flow law of the gas injection wellbore is the key to achieving safe and efficient CO2 injection. The existing wellbore flow model lacks research on the corrosion law. To this end, this paper established a gas injection wellbore flow-heat transfer-corrosion coupling model based on the actual situation of Huang 3 District of the CCUS Demonstration Base of Changqing Oilfield. The field measured data verification showed that the relative average error of the model in predicting pressure and temperature was less than 7.5% and the R2 of the predicted value and the measured value was greater than 0.99. The model was used for sensitivity analysis to evaluate the effects of different gas injection temperatures (15–55 °C), pressures (15–55 MPa), displacements (10–500 t/d) and CO2 contents (50–100%) on wellbore temperature, pressure and corrosion rate, and the wellbore flow law under different gas injection conditions was clarified. The results show that the wellbore temperature, pressure and corrosion rate are significantly affected by gas injection parameters. The wellbore temperature increases with the increase of gas injection temperature and decreases with the increase of gas injection displacement. The wellbore pressure is positively correlated with the gas injection pressure and CO2 content and the gas injection temperature and displacement have little effect on the pressure. The corrosion rate increases with the increase of gas injection temperature and displacement and decreases with the increase of gas injection pressure. In the wellbore, it shows a trend of first increasing and then decreasing with depth. The wellbore corrosion rate is affected by many factors. Reasonable adjustment of gas injection parameters (lowering temperature, increasing pressure, controlling displacement and CO2 content) can effectively slow down the wellbore corrosion loss. The research results can provide a theoretical basis for the optimization of gas injection system.

Efficacy of a simple intravitreal perfluoropropane injection in treating unclosed idiopathic macular holes following vitrectomy

BackgroundThis study aimed to evaluate the efficacy of a simple intravitreal injection of perfluoropropane (C3F8) in treating unclosed idiopathic macular holes (IMHs) in patients who had previously undergone primary pars plana vitrectomy (PPV).MethodsThis study was a retrospective, observational clinical study. It included patients diagnosed with unclosed IMHs following primary PPV combined with internal limiting membrane peeling and air tamponade. Optical coherence tomography (OCT) performed 1 week after PPV revealed unclosed IMHs with the presence of the ‘cuff’ sign and intraretinal cysts. The following day, these patients received a simple intravitreal C3F8 injection. Comprehensive evaluations, including best-corrected visual acuity (BCVA), indirect ophthalmoscopy, fundus photography, and OCT, were performed before PPV, 1 week after surgery, and at follow-up intervals of 1–3 months after the intravitreal gas injection.ResultsThe minimum linear diameter (MLD) of the macular holes (MHs) 1 week before C3F8 injection was 335.1 ± 74.3 μm. Following C3F8 tamponade, the closure rate of the MHs was 100%. The mean BCVA before C3F8 tamponade was 0.68 ± 0.17 logMAR (20/100) after primary PPV, which improved to 0.48 ± 0.19 logMAR (20/63) after C3F8 tamponade, showing a statistically significant difference (P = 0.01).ConclusionsFor patients with unclosed MHs after primary PPV, the presence of the ‘cuff’ sign on OCT suggests that retreatment can be effectively achieved through a simple intravitreal gas injection. This approach is straightforward, practical, and effective.

Study of Grain Boundary: From Crystallization Engineering to Machine Learning

Grain boundaries play a vital role in determining the structural, functional, mechanical, and electrical properties of semiconductor materials. Recent studies have yielded great advances in understanding and modulating the grain boundaries via semiconductor crystallization engineering and machine learning. In this article, we first provide a review of the miscellaneous methods and approaches that effectively control the nucleation formation, semiconductor crystallization, and grain boundary of organic semiconductors. Using the benchmark small molecular semiconductor 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) as a representative example, the crystallization engineering methods include polymer additive mixing, solvent annealing, gas injection, and substrate temperature control. By studying the grain-width-dependent charge transport, we propose a grain boundary model as a fundamental basis to theoretically understand the intrinsic relation between grain boundary engineering and charge carrier mobility. Furthermore, we discuss the various machine learning algorithms and models used to analyze grain boundaries for the various important traits and properties, such as grain boundary crystallography, energy, mobility, and dislocation density. This work highlights the unique advantages of both crystallization engineering and machine learning methods, demonstrates new insights into discovering the presence of grain boundaries and understanding new properties of materials, and sheds light on the great potential of material application in various fields, such as organic electronics.

Experimental study on the influence of gas injection on Flashing in open natural circulation systems under stable boundary conditions

As an efficient passive heat exchange system, natural circulation systems are widely used in various fields, including passive containment cooling system in nuclear power plants. Flashing is the most common two-phase flow state in natural circulation systems. To enhance the circulation capacity and stability of natural circulation systems, this study conducts experiments on the effects of gas injection on flashing two-phase flow using water and air as mediums. The research analyzes the impact of different gas injection positions and volumes on the flow rate, flow pattern, flow instability, and void fraction of the flashing flow. The results indicate that gas injection enhances the circulation flow rate of the loop and improves system stability. The further the gas injection position is from the upstream of the flashing point, the better the enhancement effect on the circulation flow rate. As the gas injection volume increases, the circulation capacity of the loop strengthens; however, once a certain injection volume is reached, the circulation capacity no longer increases, with a maximum enhancement of up to 80% in circulation flow rate. The introduction of gas injection leads to significant fluctuations in the axial distribution of the void fraction in the rising section, but has a negligible effect on the bubble fraction at the exit of the rising section. The paper analyzes the pressure drops and driving force fractions in the rising section before and after gas injection, and presents the mechanisms by which different gas injection positions and amounts affect the flow in the loop. These findings provide important insights for enhancing and stabilizing natural circulation systems, contributing to improved design and operation of passive safety shell cooling systems.

Enhancing oil recovery and carbon sequestration through alternating injection of methane-rich associated gas and CO2 in deep reservoirs

The direct emission of methane-rich associated gas from oil fields is a significant contributor to the greenhouse effect. Currently, alternative gas flooding predominantly employs CO2 and N2 as displacement phases, with limited research focusing on the alternating injection of methane-rich associated gas and CO2 tailored for oil field production. This study investigates the feasibility of enhancing oil recovery and mitigating the greenhouse effect through the alternating injection of methane-rich associated gas and CO2 into reservoirs using experimental and numerical simulation approaches. Initially, core-scale laboratory experiments were conducted on the alternating injection of methane-rich associated gas and CO2, followed by establishing a corresponding numerical simulation model. The results indicate that, compared to continuous CO2 injection, the alternating injection method results in a 2.48% reduction in oil recovery efficiency. However, this method demonstrates superior control over the mobility of oil, gas, and water. This is because there are two ways to enhance oil recovery efficiency: improve extraction efficiency and increase the swept area. CO2 has a high extraction efficiency but a relatively small swept area. Therefore, we aim to increase the swept area by using an alternating injection method of CO2 and associated gas, where mobility is a key factor in expanding the swept area. Specifically, the mobility ratio between oil and gas decreases from 9.65 to 8.24, and the ratio of oil mobility in the remobilized zone to water mobility in the unswept zone reduces from 0.770 to 0.441, suggesting significant potential for improving the sweep efficiency of heterogeneous reservoirs through alternating injection. Subsequently, numerical simulations were performed at the reservoir scale to investigate the alternating injections of methane-rich associated gas and CO2 with varying slug sizes. At the reservoir scale, compared to continuous CO2 injection, the alternating injection method increases the swept area of injected gas from 4.72 to 7.82 km2, consequently resulting in an additional production of 18 969 m3 of oil and sequestration of 9.0619 × 108 kg CO2 equivalents, representing increases of 15.6% and 460.4%, respectively. Finally, the slug ratio for alternating injection was optimized using the surrogate optimization method in MATLAB. After optimization, the cumulative oil production increased by 31.6% and the carbon sequestration capacity increased by 74.1%, compared to continuous CO2 flooding. This study offers valuable theoretical support for improving oil recovery through gas injection and facilitating carbon sequestration in reservoirs.

Hydro-mechanical insights for radioactive waste disposal from gas injection experiments in shale

Hydro-mechanical insights for radioactive waste disposal from gas injection experiments in shale

Optimization Design of Gas Injection and Brine Discharge Process Parameters in Salt Cavern Gas Storage

Optimization Design of Gas Injection and Brine Discharge Process Parameters in Salt Cavern Gas Storage

Estimation of minimum miscible pressure in carbon dioxide gas injection using machine learning methods

Estimation of minimum miscible pressure in carbon dioxide gas injection using machine learning methods

Capabilities of text-to-text large language models in seismic velocity estimation of CO2- or H2-saturated rocks

Since the release of ChatGPT in 2022, generative artificial intelligence powered by large language models (LLMs) has gained significant traction, demonstrating its potential across various fields. This study explores the capability of pretrained text-to-text LLMs in rock physics modeling, focusing specifically on estimating seismic velocities in CO2- or H2-saturated rocks. Such estimations are essential for subsurface gas storage, a crucial component in advancing the energy transition and achieving decarbonization goals. These gas injections alter rock elastic properties, such as seismic velocities and density, necessitating accurate monitoring. While existing methods rely on theories, empirical relations, and machine learning, these methods face challenges like data scarcity and model uncertainty. We evaluate four popular language models — GPT-4o, GPT-4o mini, GPT-4 turbo, and Claude 3.5 Sonnet — in blind tests using experimental benchmark data to assess their ability to optimize model selection and parameter determination in rock physics.

Pure CO2 and impure CO2-SO2-NO-O2 reactions with carbon storage site underlying seals: Coaly mudstones and carbonate cemented sandstones.

The transition to net zero emissions requires the capture of carbon dioxide from industrial point sources, and direct air capture (DAC) from the atmosphere for geological storage. Dissolved CO2 has reactivity to rock core, and while the majority of previous studies have concentrated on reservoir rock or cap-rock reactivity, the underlying seal formation may also react with CO2. Drill core from the underlying seal of a target CO2 storage site was reacted at in situ conditions with pure CO2, and compared with an impure CO2 stream with SO2, NO and O2 that could be expected from hard to abate industries. Argillaceous sandstones, mudstones, coaly mudstones, and carbonate cemented sandstones of the Moolayember Formation, Bowen Basin, had significant natural alteration of feldspar to kaolinite creating porosity, with clays, siderite and textured ankerite filling and rimming porosities of 3.5 to 15.8%. Synchrotron XFM quantified Mn mainly hosted in siderite veins and cements, Sr and Rb in feldspar, and Pb, Th and Sr in monazite. Pb was also in siderite; with As mainly in pyrite and associated with ankerite. On pure CO2 or impure CO2 reaction, ankerite and siderite dissolution, Fe-chlorite leaching, and apatite or sulphide alteration occurred. With the impure CO2 stream Fe-oxides precipitated on rock surfaces especially in argillaceous sandstone. Ferroan carbonates, calcite, and Fe oxides containing Cr were also precipitated. Ankerite and siderite dissolution released increasing concentrations of dissolved Ca, Mg and Mn from carbonate cemented core that were higher with mixed gas injection. Argillaceous sandstone however released higher concentrations Si, Rb, Co and Zn. Dissolved Fe initially increased then decreased in impure gas experiments via Fe oxide precipitation, and Pb, Ni, Cr, REE also increased and subsequently decreased. Geochemical modelling predicted that Fe was mobilised mainly from reaction of siderite and Fe chlorite. Mainly carbonates (siderite, ankerite) and chlorite dissolution released trace metals, with several metals also initially mobilised by desorption and exchange. Precipitated Fe oxides provided adsorption sites to adsorb a portion of metals from solution. These reactions are also relevant to CO2 streams from DAC that could be expected to contain O2 and to potential reactions in overlying aquifers.

Impact of gas composition, pressure, and temperature on interfacial Tension dynamics in CO₂-Enhanced oil recovery.

Climate change policies are driving the oil and gas industry to explore CO2 injection for carbon dioxide storage in reservoirs. In the United States, a substantial portion of oil production relies on CO2-enhanced-oil-recovery (CO2-EOR), demonstrating a growing interest in using CO2 to address various production challenges like condensate mitigation, pressure maintenance, and enhancing productivity in tight reservoirs. CO2 injection introduces gases like natural gas and N2, either pre-existing or as impurities in the injected CO2 gas. These gases alter the interaction of CO2 with the oil or condensate in the reservoir, with interfacial tension playing a crucial role in governing miscibility, mobilization, and phase distribution. Effectively implementing gas injection techniques requires a precise understanding of interfacial tension between injected gases and reservoir fluid under reservoir conditions. This study aims to evaluate the effects of oil composition, gas composition, pressure, and, temperature on interfacial tension and provides a comprehensive understanding of IFT dynamics for CO2-EOR implementation. The study utilizes the pendant drop analysis technique to assess the impact of pressure, temperature, and gas composition on crude oil and condensate interfacial tension. Measurements span a range of temperature (30-85 oC), pressure (0.7-7MPa), and mixture composition (CO2: N2 ratios of 90:10 and 10:90), including pure CO2 and N2 with crude oil and condensate. Accurate measurement of interfacial tension incorporates changes in oil and gas density as functions of pressure and temperature. Results show that interfacial tension is significantly influenced by pressure, temperature, and gas composition. It decreases with increasing pressure at constant temperature and gas composition for both crude oil and condensate. While temperature-induced reductions in interfacial tension occur, they are overshadowed by the more pronounced effect of pressure. Gas composition significantly affects system interfacial tension; an increase in CO2 mole fraction decreases it, while an increase in N2 mole fraction causes an upturn. Changes in CO2 mole fraction result in concave downward trends, whereas changes in N2 mole fraction lead to concave upward trends. These findings are crucial for understanding the interaction of injected gas with reservoir fluid and can be applied to model interfacial tension with hydrocarbon fluid. This study offers an in-depth understanding of interfacial tension dynamics in CO2-EOR, a process that is increasingly attracting global attention for CO2 utilization. The research stands out for its innovative experimentation and detailed analysis, which focus on evaluating the impact of individual parameters crucial for modeling. Additionally, it sheds light on the combined effects of these parameters, which are essential for practical field applications. This knowledge is instrumental in designing processes such as CO2-EOR and condensate banking, incorporating the effects of pressure, temperature, and gas composition at the reservoir scale.

Optimizing Nanobubble Production in Ceramic Membranes: Effects of Pore Size, Surface Hydrophobicity, and Flow Conditions on Bubble Characteristics and Oxygenation.

Precise control of nanobubble size is essential for optimizing the efficiency and performance of nanobubble applications across diverse fields, such as agriculture, water treatment, and medicine. Producing fine bubbles, including nanobubbles, is commonly achieved by purging gas through porous media, such as ceramic or polymer membranes. Many operational factors and membrane properties can significantly influence nanobubble production and characteristics. This study examines how membrane pore size, surface hydrophobicity, and gas/water flow conditions affect nanobubble size and concentration. Findings reveal that reducing the ceramic membrane pore size from 200 to 10 nm slightly decreased the mean nanobubble diameter from 115 to 89 nm. Furthermore, membranes with a hydrophilic outer surface and hydrophobic pore surface generated smaller nanobubbles with higher concentrations in water. Additionally, a high water cross-flow rate (e.g., >1 L·min-1) increased the nanobubble concentration, though bubble size remained unaffected. In contrast, the gas flow rate had a more pronounced effect. Increasing the gas flow rate from 0.5 to 12 L·min-1 significantly raised the nanobubble concentration from 3.09 × 108 to 1.24 × 109 bubbles·mL-1 while reducing the mean bubble diameter from 100 to 79 nm. An interfacial force model was applied to analyze bubble detachment at the membrane pore outlet, considering factors such as gas flow/pressure, surface tension, and shear forces from the water flow. These findings offer valuable insights into the mechanisms governing nanobubble generation via gas injection through porous membranes.

Research and Prospect of CCUS‐EOR Technology and Carbon Emission Reduction Accounting Evaluation

ABSTRACTAs a potential carbon emission reduction measure, carbon capture, utilization and storage technology is of great significance to achieve the goals of “carbon peak” and “carbon neutrality.” The implementation of carbon capture, utilization, and storage‐enhanced oil recovery (CCUS‐EOR) in the oil and gas industry serves the dual purpose of utilizing greenhouse gases as resources and enhancing oil recovery. This approach is a key strategy for achieving carbon emission reductions. In this study, the key problems of source‐sink matching, injection mode, oil displacement storage, and leakage were analyzed in conjunction with CCUS‐EOR technology used in both domestic and foreign oil fields. Additionally, the carbon emission reduction accounting methods of different oil fields were compared. Carbon source, carbon dioxide concentration, capture, and transportation mode are important influencing factors of carbon source selection. The project should follow the principle of proximity and select high‐concentration gas source as the development object in the early stage; the main methods of carbon dioxide injection are continuous carbon dioxide injection, alternating water and gas injection, and CO2 huff and puff among which injection speed and injection pressure are the key parameters; the underground occurrence state and storage capacity of carbon dioxide gas are dynamic changes in the process of oil displacement and storage; the three parts of surface leakage, injection wellbore leakage, and production well production are the key points of CCUS‐EOR project leakage. The corresponding monitoring methods are analyzed for different leakage modes; the CCUS‐EOR carbon emission reduction accounting method is comprehensively analyzed, and the application of carbon emission reduction accounting methods in major oilfields is compared. The accounting method of “life cycle assessment (LCA) + emission factor method + actual measurement method” is proposed. The research holds significant importance for enhancing the entire CCUS‐EOR technology chain and refining the CCUS‐EOR emission reduction accounting methodology. It also facilitates the integration of CCUS‐EOR projects into the carbon trading market, thereby enabling the efficient development of carbon assets in carbon dioxide flooding projects within oil and gas fields.

Evaluating Nitrogen Gas Injection Performance for Enhanced Oil Recovery in Fractured Basement Complex Reservoirs: Experiments and Modeling Approaches

This study explored the effectiveness of gas injection for enhanced oil recovery (EOR) in fractured basement complex reservoirs, combining laboratory experiments with numerical simulation analyses. The experiments simulated typical field conditions, focusing on understanding the interaction between the injected gas and the reservoir’s fracture–matrix system. The laboratory results showed that under the current reservoir pressure and temperature conditions, nitrogen gas flooding in the fractured matrix achieved a superior oil recovery efficiency compared to that of the other gases tested (CO2, APG, and oxygen-reduced air), exhibiting the most favorable movable oil saturation range and the lowest residual oil saturation. To evaluate the performance of nitrogen gas injection in a fractured basement complex reservoir, a 3D reservoir model with complex natural fractures was built in a numerical reservoir simulator. Special methods were required for the geological modeling and reservoir simulation, with the specific principles outlined. Numerical simulations of gas injection into fractured basement complex reservoirs revealed that cyclic gas injection was identified as the most effective strategy, balancing incremental oil recovery with minimized gas channeling risks. This study demonstrated that the optimal injection location and rate are crucial factors affecting the recovery performance. These findings provided actionable insights for implementing gas injection EOR strategies in fractured basement complex reservoirs, highlighting the importance of optimizing the injection parameters to maximize the recovery.

Research and Application of Oxygen-Reduced-Air-Assisted Gravity Drainage for Enhanced Oil Recovery

This paper summarizes the research progress and applications of oxygen-reduced-air-assisted gravity drainage (OAGD) in enhanced oil recovery (EOR). The fundamental principles and key technologies of OAGD are introduced, along with a review of domestic and international field trials. Factors influencing displacement performance, including low-temperature oxidation reactions, injection rates, and reservoir dip angles, are discussed in detail. The findings reveal that low-temperature oxidation significantly improves the recovery efficiency through the dynamic balance of light hydrocarbon volatilization and fuel deposition, coupled with the synergistic optimization of the reservoir temperature, pressure, and oxygen concentration. Proper control of the injection rate stabilizes the oil–gas interface, expands the swept volume, and delays gas channeling. High-dip reservoirs, benefiting from enhanced gravity segregation, demonstrate superior displacement efficiency. Finally, the paper highlights future directions, including the optimization of injection parameters, deepening studies on reservoir chemical reaction mechanisms, and integrating intelligent gas injection technologies to enhance the effectiveness and economic viability of OAGD in complex reservoirs.

Analysis of geological characteristics and potential factors of formation damage in coalbed methane reservoir in Northern Qinshui basin

Given the suboptimal physical properties and distinctive geological conditions of deep coalbed methane reservoirs, any reservoir damage that occurs becomes irreversible. Consequently, the protection of these deep coalbed methane reservoirs is of paramount importance. This study employs experimental techniques such as scanning electron microscopy, X-ray diffraction, and micro-CT imaging to conduct a comprehensive analysis of the pore structure, mineral composition, fluid characteristics, and wettability of coal seams 3# and 15# in the northern Qinshui Basin of China. The objective is to elucidate the types of reservoir damage induced by fracturing fluid intrusion along with potential contributing factors. This research is critical for ensuring safe drilling practices, effective gas injection, and efficient development strategies for coalbed methane reservoirs. The findings indicate that the mineral composition of the coal rock consists of 18.52% clay minerals, 34% quartz, and 8.98% calcite. Furthermore, hydrophilicity and natural fractures within the coal rock may lead to water-sensitivity, velocity- sensitivity, alkali- sensitivity, and acid- sensitivity damages to the coalbed methane reservoir. There exists good compatibility between fracturing fluids and both coal rock as well as formation water. The fine particles generated from hydraulic fracturing are prone to transport through the coal seam while obstructing pore throats. Thus exhibiting pronounced velocity sensitivity characteristics in this reservoir type. Coal rock demonstrates pronounced stress sensitivity. As the effective stress escalates from 2 MPa to 10 MPa, there is a marked decrease in the permeability of coal rock. With increasing effective stress, the pore structure and natural fractures within the coal rock are compressed more tightly, resulting in a diminished permeability of the coal rock. When exposed to fracturing fluid saturation, not only does the volume of these particles expand but they can also cause blockages that result in up to a 60% reduction in fracture flow capacity. These insights are vital for optimizing fracturing designs aimed at protecting reservoir integrity.

Investigation on Flow Features and Combustion Characteristics in a Boron-Based Solid-Ducted Rocket Engine

Numerical and experimental approaches are conducted to investigate the flow features and secondary combustion performance induced by different air–fuel ratios in a boron-based solid-ducted rocket engine. The results indicated that the afterburning chamber flow features become more complicated owing to the multiple nozzles of the gas injector, and a number of recirculation zones are generated. Because of this, the mixing of the fuel gas and incoming air is enhanced. When the air–fuel ratio decreases, the heat release in the afterburning chamber increases continuously, which causes the pre-combustion shock train to continue to propagate upstream in the subsonic diffuser of the inlet isolator, along with the boundary layer separation zone also moving forward, and the stability margin of the direct-connect inlet decreasing gradually. Furthermore, the direct-connect inlet works at a critical state with an air–fuel ratio of 11.5. As the mass flow rate of the fuel-rich gas rises gradually, the engine thrust gradually increases, and the number of vortexes in the afterburning chamber and the corresponding region affected by the vortexes generally decrease. Meanwhile, the mixing and combustion of the fuel-rich gas and incoming flow were not substantially changed. Additionally, the combustion efficiency and specific impulse are proportional to the air fuel ratio.

The Role of Technological Innovations in Improving Oil Extraction Efficiency in South Sudan

Purpose: The purpose of this study was to explore the role of technological innovations in improving oil extraction efficiency in South Sudan, with a specific focus on recovery rates, operational costs, reservoir management, and real-time data accuracy. Methodology: In the research, a descriptive methodology was used to find out the effect of the contributing factors on the oil production results. Findings: Results show that EOR methods, such as reactive injection of water (CW), clearly increase the recovery yield, and reactive injection of gas (GE) technologies obviously enhance the recovery efficiency and the energy security. Further, real-time information systems and modern reservoir management techniques facilitate better decision-making, more efficient production activities and are also scarcity-reducing. Nonetheless, development of South Sudan's oil sector is constrained by the presence of outdated infrastructure, lack of technical ability and insufficient funding for technology. Unique Contribution to Theory, Practice and Policy: The conclusion reached from the study is that these innovations are necessary to help with maximizing resource use, to help with cost reduction and to enable sustainable development in the country's oil industry. Target areas of advice include giving importance to EOR methods, incorporating real-time data technology, and developing technical capacity to modernise the South Sudan oil industry.

OPTIC PIT-LIKE MACULOPATHY WITH CLINICALLY OCCULT OPTIC DISC PIT Diagnostic imaging, clinical features, and management

Purpose: To describe the diagnostic imaging, clinical features and management of pit-like maculopathy and clinically occult optic pit (OOPM). Methods: We retrospectively analyzed the demographics, imaging features and intervention details of the subjects with OOPM enrolled from 19 sites. The main outcome measure was detection of occult pit in OOPM. Results: Forty-seven eyes (46 subjects) with pit-like maculopathy without visible optic pit were studied. Maculopathy consisted of multilayered retinoschisis and/or serous detachment (44 eyes); 3 eyes showed non-glaucomatous nerve fiber layer defects. Optical coherence tomography (OCT) revealed a crater-like disc cavitation in 40 (85%) eyes. Infrared imaging and fluorescein angiography, when performed, revealed the occult pit in 5/18 (29%) and 3/13 (23%) eyes respectively. Clinical clues to an occult pit included anomalous or enlarged ONH and cilioretinal artery (36%, 33% and 32% eyes respectively). Twelve (26%) eyes had coexistent glaucoma. Follow-up was available for 35 (75%) eyes: 22 were observed; 11 underwent vitrectomy; 2 had gas injection. Intervention reduced macular fluid in 85% eyes and improved best-corrected visual acuity (p=0.012). Conclusions: OCT revealed a cavitation attributable to optic pit in most eyes with pit-like maculopathy, helped by clinical clues like anomalous/enlarged disc, and cilioretinal artery. Surgical intervention was infrequent but successful.

Targeted Comparative Analysis of Gas Injection Strategies to Enhance Hydrodynamic Cavitation for Effective Wastewater Treatment

Targeted Comparative Analysis of Gas Injection Strategies to Enhance Hydrodynamic Cavitation for Effective Wastewater Treatment