Search Results (53)

The steam flooding–gravity drainage technology has become one of the effective alternative development methods in the middle and later stages of thin-layer ultra-viscous oil steam throughput, with predicted recovery rate of over 50%. Currently, there is a lack of relevant technical research on the composite swallowing and spitting preheating stage. This is in response to the slow preheating of the oilfield and the large differences in connectivity between injection and production wells. The dynamic analysis method was used to analyze the key factors that restrict the efficient connectivity of steam throughput preheating. Based on this, a series steam throughput preheating efficient connectivity technologies were proposed. Physical simulation, numerical simulation, and other methods were used to characterize and demonstrate the technical principles and operating of the efficient connectivity technology. The research results were successfully applied to the super-viscous oil reservoirs of the Fengcheng oilfield in Xinjiang. The results show that the main factors severely limiting the balanced and rapid connectivity between injection and production wells are the limited radius of steam coverage, low utilization degree oil layers, and frequent unilateral steam breakthroughs. The reservoir expansion transformation has improved the reservoir properties along the horizontal section, increasing the utilization rate of the horizontal section from 51% to 90%, achieving rapid connectivity injection and production wells, and shortening the conventional throughput preheating cycle by 3–4 cycles. The group combination steam injection method achieved a centralized increase in thermal energy, with the inter-well connectivity changing from unidirectional to a broader area The reasonable steam injection intensity was 15 t/m, the regional temperature field increased from 83 °C to 112 °C, and the steam area expanded by approximately 10 m. The multi-medium composite technology achieved a dual increase in steam coverage and profile utilization, with the steam coverage radius increasing by 15 m and the oil reservoir profile utilization increasing by more than 30%. The temporary plugging and fracturing of the reservoir achieved the sealing of inherited breakthrough channels, directing the steam to unused areas, increasing the utilization rate to 89.2%, and shortening the throughput preheating cycle by 3 cycles. This series of technologies has achieved remarkable results in actual application in super-heavy oilfield, which has certain reference significance for the efficient and low-carbon development of heavy oil steam throughput reservoir turning into drive and release. Full article

The air injection for brine drainage affects the thermodynamic characteristics of salt caverns in the operation of compressed air energy storage (CAES). This study develops a thermodynamic model to predict temperature and pressure variations during brine drainage and operational cycles, validated against Huntorf plant data. Results demonstrate that increasing the air injection flow rate from 80 to 120 kg/s reduces the brine drainage initiation time by up to 47.3% and lowers the terminal brine drainage pressure by 0.62 MPa, while raising the maximum air temperature by 4.9 K. Similarly, expanding the brine drainage pipeline cross-sectional area from 2.99 m² to 9.57 m² reduces the total drainage time by 33.7%. Crucially, these parameters determine the initial pressure and temperature at the completion of brine drainage, which subsequently shape the pressure bounds of the operational cycles, with variations reaching 691.5 kPa, and the peak temperature fluctuations, with differences of up to 4.9 K during the first cycle. This research offers insights into optimizing the design and operation of the CAES system with salt cavern air storage. Full article

This study investigates the feasibility and optimization of Expanding Solvent Steam-Assisted Gravity Drainage (ES-SAGD) in deep extra-heavy oil reservoirs, with a focus on the Shu 1-38-32 block in the Liaohe Basin. A modified theoretical model that accounts for steam quality reduction with increasing reservoir depth was applied to evaluate SAGD performance. The results demonstrate that declining steam quality at greater burial depths significantly reduces thermal efficiency, the oil–steam ratio (OSR), and overall recovery in conventional SAGD operations. To overcome these challenges, numerical simulations were conducted to evaluate the effect of hexane co-injection in ES-SAGD. A 3 vol% hexane concentration was found to improve oil recovery by 17.3%, increase the peak oil production rate by 36.5%, and raise the cumulative oil–steam ratio from 0.137 to 0.218 compared to conventional SAGD. Sensitivity analyses further revealed that optimal performance is achieved with cyclic injection during the horizontal expansion stage and chamber pressures maintained above 3 MPa. Field-scale forecasting based on five SAGD well pairs showed that the proposed ES-SAGD configuration could enhance the cumulative recovery factor from 28.7% to 63.3% over seven years. These findings clarify the fundamental constraints imposed by steam quality in deep reservoirs and provide practical strategies for optimizing solvent-assisted SAGD operations under such conditions. Full article

Foam-formed cellulose biocomposites provide a promising, innovative approach to creating lightweight and eco-friendly materials for utilization in packaging and insulation. This study investigates the production and characterization of temperature-resistant, mechanically stable cellulose fiber (CF) composite foams reinforced with alumina nanofibers (ANFs). To evaluate the impact of ANFs on rheology and drainage, CF suspensions were prepared at a concentration of 20 g/kg, with ANFs added at 2 wt% and 5 wt%. All foams exhibited shear-thinning behavior, with variations in flow characteristics influenced by ANF consistency and particle–bubble interactions. ANFs were integrated into the dry CF foam structure using two methods: (i) immersion in an ANF water suspension, and (ii) direct injection of the suspension into the foam matrix. Mechanical and thermal analyses of the dried CF foams with 2% ANFs demonstrated significant improvements in strength and thermal stability. Incorporating ANFs into CF-based foams enhances their rheological properties, improves mechanical and thermal performance, and reduces combustion rates. These results highlight the potential of ANF-reinforced CF foams for use in industries requiring biodegradable insulation and packaging materials. Full article

Background and Objectives: To summarize the evidence on in vivo uterine pelvic lymphatic drainage. Materials and Methods: A literature search was performed in multiple electronic databases from inception to December 2024. We included all the studies that compared two different uterine injection sites in the mapping of pelvic sentinel lymph nodes by injecting two different tracers into two distinct injection sites. The primary outcomes included the concordance and discordance rates in the mapped pelvic sentinel lymph nodes between the pairs of injection sites. The secondary outcomes were the detection rates per injection site and tracer. Four reviewers independently reviewed the records for inclusion, assessed the risk of bias, and extracted the data. Pooled concordance, discordance, and detection rates with 95% confidence intervals (CIs) were estimated using the random effects model. Heterogeneity was quantified using the I² tests. Results: Out of 2512 records, we included 4 studies (172 patients and 344 hemipelves). Three studies injected the cervix with the technetium-99m and the uterine corpus with methylene blue; one study injected the cervix with indocyanine green and the utero-ovarian ligament with methylene blue. Both tracers/injection sites successfully identified a sentinel lymph node in 132 hemipelves (132/344; 38.4%), identifying the same sentinel lymph node in 116 cases (116/132; 87.9%). The pooled concordance rate per hemipelvis was 91.8% (95% CI 0.665–1.000; I² = 92%; chi² p-value < 0.01). Two different sentinel lymph nodes were identified in the remaining 16 hemipelves, with a pooled hemipelvis discordance rate of 8.2% (95% CI 0.000–0.335; I² = 92%; chi² p-value < 0.01). The cervix and technetium-99m were the injection site and tracer with the highest pooled detection rate. Conclusions: Different uterine injection sites appear to share a common pelvic lymphatic pathway and sentinel lymph node in most cases, consistent with the current practice in endometrial cancer. Future research will confirm whether cervical injections might be proposed for pelvic sentinel lymph node mapping in all gynecological cancers. Full article

Background/Objectives: Indocyanine green (ICG)-guided near-infrared (NIR) fluorescence imaging represents a potentially advantageous approach for the identification of lymphatic drainage pathways. This study was undertaken to evaluate the efficacy of ICG-guided NIR fluorescence in mapping lymphatic drainage and facilitating sentinel lymph node biopsy (SLNB) in patients diagnosed with colon cancer. Methods: A prospective cohort of 30 consecutive patients with colon cancer undergoing surgical resection at our institution was enrolled in this study. Peritumoral injection of ICG was performed to facilitate intraoperative identification of sentinel lymph nodes (SLNs). Identified SLNs were marked and excised ex vivo following specimen retrieval. All the retrieved specimens were submitted for histopathological analysis using hematoxylin and eosin (H&E) staining. SLNs that were negative for metastatic disease upon H&E staining underwent further examination via immunohistochemistry (IHC). Results: Successful identification of SLNs was achieved in 83.33% of cases. The false positive rate was 6.6%, and the false negative rate was 8%, respectively. Atypical lymphatic drainage patterns were observed in 6.6% of the patients. Notably, the patients exhibiting atypical lymphatic drainage subsequently developed metastases during the follow-up period. Immunohistochemical analysis failed to detect micrometastases in SLNs that were initially deemed negative based on H&E staining. Conclusions: NIR–ICG fluorescence is a safe, reliable, and technically feasible method for performing SLNB in patients with colon cancer. Furthermore, this technique offers the potential for intraoperative identification of atypical lymphatic drainage pathways, which may have significant implications for determining the optimal extent of standard lymphadenectomy. Full article

As conventional oil resources decline, optimizing the development of tight reservoirs has become critical for sustaining production. Horizontal wells with artificial fractures offer a promising solution, but improper water injection often leads to uneven waterflooding, particularly in irregular horizontal–vertical well systems—a common challenge in fields like China’s Fuxian oilfield. This study tackles this issue by introducing a practical and effective method to optimize water injection flow rates, significantly enhancing oil recovery in such complex well patterns. Through advanced numerical modeling and three-dimensional flow visualization, we analyze sweep efficiency and water breakthrough risks, categorizing the horizontal well’s drainage area into three distinct regions, each requiring tailored injection rates. Using a representative model with one horizontal well and three vertical wells, we demonstrate that adjusting the flow rate ratio among injectors to 6:3:1 (instead of a uniform 1:1:1) boosts cumulative oil production by an additional 2997.6 m³. These findings provide field engineers with an actionable strategy to improve waterflooding efficiency, directly increasing recoverable reserves and economic viability in tight reservoirs. The proposed approach has immediate relevance for oilfield operations, offering a scalable solution to maximize recovery in similar unconventional reservoirs worldwide. Full article

Gangue particle entrainment during flotation remains a significant challenge in mineral processing. Previous studies have shown that incorporating inclined plates into the froth zone can reduce the recovery of fine gangue particles. However, the effects of inclined channels on froth drainage have not been fully investigated. This study employed a custom-designed forced drainage system to systematically examine the impact of inclined channels on foam drainage and the underlying mechanisms. Results revealed that, at an SDS solution injection flow rate of 36 mL/min and an inclined channel angle of 30°, the foam drainage velocity in the inclined channel was significantly higher than that in the vertical channel for both two-phase and three-phase foams. This advantage became more pronounced as the SDS injection flow rate increased. A new drainage pathway formed between the inclined wall and the foam, facilitating faster liquid flow than within the foam structure. This mechanism was identified as the primary factor enhancing foam drainage velocity in inclined channels. These findings demonstrate that inclined channels can effectively improve foam drainage efficiency compared to vertical channels, providing valuable insights for optimizing froth zone structure. Full article

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. Full article

Pancreatic cancer is associated with high rates of morbidity and mortality. Endoscopic ultrasound (EUS)-guided biopsy has become the standard diagnostic modality per the guidelines. The use of EUS has been growing for providing various treatments in patients with pancreatic cancers: biliary and gallbladder drainage for those with malignant biliary obstruction, gastroenterostomy for malignant gastric outlet obstruction, celiac plexus/ganglia neurolysis for pain control, radiofrequency ablation, placement of fiducial markers, and injection of local chemotherapeutic agents. In this review, we explore the recent clinical studies evaluating the EUS-guided treatments in pancreatic cancer. Full article

Carbonate gas reservoirs are crucial in gas field development, with carbonate bottom-water gas reservoirs being a significant subset. However, the development of these reservoirs often faces challenges such as water invasion, leading to a low gas recovery rate. Enhancing gas recovery is a primary goal for researchers in this field. This study provides a systematic review of the mechanisms, identification, and dynamic prediction of water invasion in these gas reservoirs. The technical adaptability and application range of different enhanced recovery methods are summarized, and their application effects are evaluated. The results indicate that carbonate gas reservoirs have diverse types of storage and permeability spaces, with a wide distribution of pore size scales, leading to various types of enclosed gas caused by water invasion. The prediction accuracy of water invasion models for bottom-water gas reservoirs with fractures and vugs is relatively low. Therefore, numerical simulation research on the basis of fine reservoir characterization is the key technology. The control of bottom-water invasion and the rescue measures after the bottom-water invasion are the keys to improving gas recovery, which can be divided into four types: drainage gas recovery, water control production, active drainage, and injection medium. Gas production by drainage is the main technology for improving gas recovery, among which foam drainage is the most widespread. The optimization of development parameters in production by water control has a good effect in the early stages of development. The active drainage technology on the water invasion channel is the bottom-up technology for the effective development of strong water-flooded gas reservoirs. CO₂ injection may have great potential to improve the recovery of bottom-water gas reservoirs, which is one of the important research directions under the background of “carbon peaking and carbon neutrality”. The research provides theoretical and technical reference significance for enhanced recovery of carbonate bottom-water gas reservoirs. Full article

Background and Objectives: Robot-assisted extravesical ureteral reimplantation (REVUR) has been described as valuable alternative to open reimplantation in the pediatric population. This study aimed to report the outcome of REVUR in children with complex obstructed megaureter (COM) needing ureteral dismembering and/or tapering. Materials and Methods: The records of patients with COM, who received REVUR with ureteral dismembering and/or tapering over the last 3 years (2021–2024), were retrospectively reviewed. The inclusion criteria for COM included previous surgery, paraureteral diverticula, or ectopic megaureter. Results: A total of 16 patients (15 boys), with a median age of 7.8 years (range 2–16), were treated over the study period. COM was associated with paraureteral diverticula (n = 6), previous failed endoscopic balloon dilation (n = 4), ectopic megaureter (n = 2), and previous bulking agent endoscopic injection causing iatrogenic ureteral obstruction (n = 4). Presentation symptoms included febrile urinary tract infections (n = 8), flank pain (n = 4), hematuria (n = 2), and pseudo-incontinence (n = 2). All surgical procedures were accomplished robotically without conversions or intra-operative complications. Ureteral tapering was performed in 7/16 (43.7%). The median operative time (including robot docking) was 220 min (range 155–290). The median length of stay was 3.8 days (range 3–7). The indwelling double J stent was removed 4–6 weeks postoperatively. Clavien 2 grade complications occurred postoperatively in 2/16 (12.5%). At median follow-up of 34.5 months, all patients were asymptomatic and showed improved hydroureteronephrosis on ultrasound and improved drainage on diuretic renogram. Conclusions: This study demonstrates that robot-assisted extravesical ureteral reimplantation is a safe and effective treatment for primary obstructive megaureter and other complex ureteral anomalies in our patient cohort. The procedure showed low complication rates, high success rates, and favorable long-term outcomes, supporting the feasibility and effectiveness of robotic surgery for these conditions. Full article

Lymphoscintigraphy evaluates the lymphatic system using radiocolloid compounds like ^99mTc-sulfur colloid and ^99mTc-nanocolloid, which vary in particle size and distribution timing. A local in-house Dextran kit (15–40 nm) was developed in 2005 and began clinical use in 2008 to localize sentinel lymph nodes; diagnose lymphedema; and detect lymphatic leakage. The normal drainage pattern remains unexplored. We retrospectively analyzed 84 upper extremity lymphoscintigraphies from 2008 to 2021. ^99mTc in-house Dextran was intradermally injected into both hands, followed by whole-body imaging at specified intervals (≤15 min; 16–30 min; 31–45 min; 46–60 min), with some receiving delayed imaging. Visual and quantitative analyses recorded axillary and forearm lymph nodes and liver, kidney, and urinary bladder activity. Results showed 92% (77/84) upper extremity lymphatic tract visualization within 45 min. Axillary node detection rates increased from 46% (≤15 min) to 86% (46–60 min). Delayed imaging further revealed nodes. Epitrochlear or brachial node visualization was rare (4%, 3/84). Hepatic, renal, and urinary bladder activity was noted in 54%, 71%, and 93% at 1 h, respectively. The axillary node uptake ratio was minimal (<2.5% of injection site activity; median 0.33%). This study characterizes normal upper extremity lymphatic drainage using ^99mTc in-house Dextran, offering insights into its clinical application Full article

Natural gas hydrate (NGH) trials have been performed successfully with different development methods and gas recovery drainage technologies. Multiphase flow in a wellbore and the drainage of natural gas hydrate are two important parts for its whole extraction process. Additionally, the choice of the drainage method is linked to the development method, making the drainage of NGH more complex. Jet pump drainage is usable for NGH production wells with the combined depressurization and thermal stimulation method. The objective of this study is to shed more light on the multiphase flow behavior in jet pump drainage and NGH production wells and put forward suggestions for adjusting heat injection parameters. The mechanism of jet pump drainage recovery technology for NGH wells was analyzed and its applicability to NGH development by the combined depressurization and thermal stimulation method was demonstrated. In addition, multiphase flow models of tubing and annulus were established, respectively, for the phenomenon of the countercurrent flow of heat exchange in the process of jet pump drainage and gas production, and the corresponding multiphase flow laws were derived. On the basis of these studies, sensitivity analysis and the optimization of thermal stimulation parameters were conducted. It is demonstrated that jet pump drainage gas recovery technology is feasible for the development of onshore NGH with the combined depressurization and thermal stimulation method. The laws of multiphase flow in the tubing and annulus of jet pump drainage and NGH production wells were disclosed in this study. Numerical simulation results show that the temperature and pressure profiles along the wellbore of jet pump drainage and NGH production wells during the drainage recovery process are affected by injection conditions. Increasing injection rate and injection temperature can both improve the effect of heat injection and reduce the hydrate reformation risk in the bottom of the annulus. This study offers a theoretical basis and technical support for production optimization and hydrate prevention and control in the wellbore of jet pump drainage and NGH production wells. Full article

The steam assisted gravity drainage (SAGD) process requires high energy input to maintain the continuous expansion of the steam chamber for achieving high oil recovery. In the late stage of SAGD operation where the oil rate is low and the heat loss is high from a mature steam chamber, maintaining steam chamber pressure with a lower steam injection is the key to maintaining the economic oil-to-steam ratio (OSR). Both laboratory studies and field tests have demonstrated the effectiveness of adding a non-condensable gas (NCG) to the SAGD steam chamber for improving the overall thermal efficiency. In this study, a multi-well reservoir model was built based on the detailed geological description from an operating SAGD project area, which contains thick pay and top water. Grounded with the history matching of more than 20 years of production using CSS (cyclic steam stimulation) and SAGD as follow-up process, the model was applied to optimize the operating strategies for the late stage of SAGD production. The results from this study demonstrated that the co-injection of steam with CO₂ or the injection of CO₂ only has potential to improve the OSR and reduce emissions by more than 50% through the improvement in steam-saving and the storage of CO₂. The results from reservoir modeling indicate that, with the current volume of a steam chamber and an operating pressure of 4.0 MPa, about 55 sm³ of CO₂ could be sequestrated and utilized for producing 1.0 m³ of oil from this reservoir through the replacement of a steam injection with CO₂ in the late stage of SAGD operation. Full article