Fluid Sequestration Research Articles

One-dimensional modelling of air injection into abandoned oil fields for heat generation

With the global drive for net-zero emissions, it has never been more important to find clean energy sources. There are thousands of abandoned oilfields worldwide with the potential to be reactivated to produce clean energy with air injection and subsequent waste fluid sequestration. Air injection, and the development of a fire-front, may be used with enhanced geothermal systems by taking advantage of the inherent increase in heat and pressure. Conventionally used as an enhanced oil recovery technique, air injection has gained the reputation of being a high-risk intervention due to the many failures in its history. Knowledge of how petrophysical rock properties and oil physical and chemical properties control the consequences of air injection is key to optimzing the selection of late-life, or even abandoned oilfields for use in such systems. Here we use one-dimensional modelling to test the effect of varying porosity, permeability, oil viscosity and API gravity on the success of air injection. Modelling shows that the most important factor controlling temperature is the porosity of the reservoir, followed by the API gravity and then the viscosity of the oil. The most important factors controlling velocity of the fire-front are API gravity followed by oil viscosity. We show that reservoirs with high porosity and low permeability with high viscosity and low API gravity oil reach the highest fire-front temperatures. The significance of this work is that it provides several geoscience-related criteria to rank possible candidate reservoirs for reactivation and clean energy generation via air injection: the best candidates will have the highest total porosity, relatively low permeability, highest oil viscosity and lowest API gravity, such fields can then move on to bespoke and more complex simulations.

A curious case of idiopathic eosinophilic pleural effusion post swimming pool diving

Eosinophilic pleural effusion is defined as pleural effusion with >10% eosinophil count. Even though the mechanism underlying eosinophilic pleural effusion is poorly understood, it is considered to be caused by pleural fluid sequestration of bone marrow-derived eosinophils. Even though there is a wide spectrum of diseases recognized to be associated with eosinophilic pleural effusion, including pleural irritation, trauma (hemothorax, pneumothorax, thoracic surgery), malignancy, parasitic infection, drug/toxin-induced and pulmonary embolism; almost 25% of cases remain idiopathic. We herein report a curious case of eosinophilic pleural effusion, which has developed post blunt trauma to the chest, sustained after diving into a swimming pool. The patient was extensively evaluated for possible etiologies but was found negative for any underlying known pathology that could lead to eosinophilic pleural effusion.

Study of Fluid Displacement Processes and Sequestration of CO2 in Coal Reservoirs Using Nuclear Magnetic Resonance Spectroscopy

Study of Fluid Displacement Processes and Sequestration of CO2 in Coal Reservoirs Using Nuclear Magnetic Resonance Spectroscopy

Influences of long-duration NO exposure on CO2 adsorption on coals: insights into oxy-coal burning flue gas storage in coal reservoirs

ABSTRACT Introducing oxy-coal burning flue gas into coal reservoirs has the advantages of mitigating emissions of CO2, NO x , and SO2, and producing in-situ coalbed methane (CBM). Given the characteristics of the geologic time scale for fluid sequestration, the long-duration NO exposure was conducted for various ranks of coal matrices to access the potential impacts of NO exposure on CO2 storage. Afterwards, the changes in critical physico-chemical properties and adsorbability of various ranks of coal matrices to CO2 because of long-duration NO exposure were revealed. Finally, the implications to implement oxy-coal burning flue gas sequestration in unmineable coal reservoirs with CBM production were indicated. The results demonstrate that the long-duration interaction with NO reduces the number of micro- and meso-pores of various ranks of coals, especially those with diametres below 4.00 nm. Moreover, the long-duration NO exposure reduces the oxygen-containing functional groups while significantly increasing the amine/amide-N for all the coals. The aforementioned alterations in the surface chemistry property imply that the coal matrix is capable of chemically adsorbing NO, thereby achieving its stable storage in target coal reservoirs. Given the electron donor–acceptor interactions between amine/amide-N and CO2, the NO exposure can elevate the CO2 storage capability of various ranks of coals under typical reservoir temperature and pressure. In summary, introducing oxy-coal burning flue gas into coal reservoirs is capable of stably storing critical gaseous pollutants and simultaneously enhancing the CO2 storage potential of coal reservoirs, thereby updating the existing oxy-coal burning technology and CO2 sequestration in unmineable coal reservoirs with the enhanced CBM recovery technology.

A modified Ranson score to predict disease severity, organ failure, pancreatic necrosis, and pancreatic infection in patients with acute pancreatitis.

Although there are several scoring systems currently used to predict the severity of acute pancreatitis, each of them has limitations. Determine the accuracy of a modified Ranson score in predicting disease severity and prognosis in patients with acute pancreatitis (AP). AP patients admitted or transferred to our institution were allocated to a modeling group (n = 304) or a validation group (n = 192). A modified Ranson score was determined by excluding the fluid sequestration parameter and including the modified computed tomography severity index (CTSI). The diagnostic performance of the modified Ranson score was compared with the Ranson score, modified CTSI, and bedside index of severity in acute pancreatitis (BISAP) score in predicting disease severity, organ failure, pancreatic necrosis and pancreatic infection. The modified Ranson score had significantly better accuracy that the Ranson score in predicting all four outcome measures in the modeling group and in the validation group (all p < 0.05). For the modeling group the modified Ranson score had the best accuracy for predicting disease severity and organ failure, and second-best accuracy for predicting pancreatic necrosis and pancreatic infection. For the verification group, it had the best accuracy for predicting organ failure, second-best accuracy for predicting disease severity and pancreatic necrosis, and third-best accuracy for predicting pancreatic infection. The modified Ranson score provided better accuracy than the Ranson score in predicting disease severity, organ failure, pancreatic necrosis and pancreatic infection. Relative to the other scoring systems, the modified Ranson system was superior in predicting organ failure.

Shock Index in predicting fluid resuscitation in patients with hypovolemic shock

Introduction: Hypovolemic shock is diagnosed by the signs of hemodynamic instability and when the source of volume loss is obvious. Among various types, hypovolemic shock is the most common which results either from the loss of blood from hemorrhage or from the loss of plasma alone due to extravascular fluid sequestration or gastrointestinal, urinary, and insensible losses. The objective of this research was to find the use of shock index in predicting fluid resuscitation in patients with hypovolemic shock. Methods: An analytical cross-sectional study was conducted among 120 patients with hypovolemic shock visiting to the Emergency department of College of Medical Sciences and Teaching Hospital from July 2022 to September 2022. Data was collected from patients and checked for completeness, accuracy and then entered and analyzed using SPSS-20. Data was analyzed using descriptive and inferential statistical tools. P-value &lt;0.05 was considered as statistically significant. Results: Out of 120 patients, majority of the patients were &gt;50 years. Minority of the patients only required blood transfusion. Among total patients 60% of the patients were admitted in ICU, 25% of them were admitted in ward and 4.17% of them were expired. In 60% cases shock index was &lt;1 while in 40% case shock index was ≥1. The number of patients receiving blood transfusion at ER increased with increase in shock index and that the number of patients with hypovolemic shock are admitted in hospital more in shock index category ≥1 as compared to shock index &lt;1 (p-value &lt;0.05). Conclusions: This study reveals that shock index is accurate in predicting the amount of fluid. The risk of all clinical complication is increased with increase in shock index.

MORPHOFUNCTIONAL CHANGES IN GASTROINTESTINAL TRACT OF RATS DURING SULFUR MUSTARD INTOXICATION

Sulfur mustard (SM) is a highly toxic blistering agent (vesicant) that has been widely used as a chemical weapon in wars and armed conflicts. Not only highly effective antidotes, but also tools for pathogenetic therapy of SM-induced lesions currently are not available, which necessitates further research in this field. Aim of the study: to examine the morphofunctional changes in gastrointestinal tract of rats during SM intoxication. Materials and methods. In experiments on rats during SM intoxication the severity of diarrhoea, propulsive activity and the specific mass of gastrointestinal tract were assessed, as well as performed a pathomorphological study of the small intestine. Results of the study. The obtained data indicate the development of the combined motor-evacuation, barrier, secretory-absorption and digestive intestinal dysfunction during SM intoxication. Conclusions. According to the authors, syndrome of intestinal insufficient is an important component of patho- and thanatogenesis of SM intoxication. Moreover, fluid sequestration and endocavitary pressure increase in gastrointestinal tract, which develop in consequence of its functional inability, should be considered as additional pathogenetic components of intoxication.

Factors Associated with Fluid Sequestration in Patients with Acute Pancreatitis: A Prospective Study in Tertiary Centre Hospital in Nepal.

Background Acute pancreatitis (AP) is associated with extensive fluid sequestration. The aim of this study was to determine association of fluid sequestration at 48 hours after hospital admission (FS48) in AP patients with demographics, clinical parameters, and outcomes of AP. Methods A prospective observational study was carried out on all adult patients with AP admitted to Tribhuvan University Teaching Hospital, Nepal, from January to September 2017. FS48 was calculated as the difference between fluid input and output in the first 48 hours of admission. The Kruskal-Wallis test with post hoc Dunn's test examined the difference in FS48 between mild AP, moderately severe AP, and severe AP. Linear regression analysis was used to evaluate association between FS48 with patients' characteristics and outcomes of AP. Outcomes of AP assessed included pancreatic necrosis, persistent organ failure, length of stay, and in-hospital mortality. Results Eighty patients (median age 44 years; 57% male) with a median FS48 of 1610 mL were evaluated. The median FS48 for mild AP, moderately severe AP, and severe AP were 1,180 mL, 2,380 mL, and 3,500 mL, respectively. There was a significant difference in pairwise comparisons between mild AP and moderately severe AP, along with mild AP and severe AP. Younger age, other etiology, and higher creatinine were independently associated with increased FS48. Increased FS48 was significantly associated with pancreatic necrosis, persistent organ failure, and in-hospital mortality. Conclusions In our study population, younger age and higher creatinine were predictors of increased FS48. Increased FS48 was associated with poorer outcomes of AP.

Left displacement of the abomasum in a reticulated giraffe bull in managed care.

A 10-y-old giraffe (Giraffa camelopardalis reticulata) bull developed colic after a 3-mo history of reduced feed consumption. Physical examination and management were performed with 2 standing sedations. The giraffe developed metabolic alkalosis and progressive pre-renal azotemia followed by compensatory respiratory acidosis and paradoxical aciduria. A metallic "ping" sound was auscultated on the left side near ribs 10-12. The giraffe was euthanized given the grave prognosis, and postmortem examination confirmed left displacement of the abomasum (LDA) with fluid sequestration (150-190 L [40-50 gal]) within the rumen. Dental disease was evident at postmortem examination and perimortem skull computed tomography. To ensure cases of LDA are not overlooked, the position of the abomasum must be noted during postmortem examination prior to removal of the gastrointestinal tract. The risk factors for the development of LDA in giraffes are not known, and associations such as those of dairy cattle (hypocalcemia, high-concentrate low-fiber diet, and indoor housing) remain to be elucidated.

Potential for geothermal heat mining by analysis of the numerical simulation parameters in proposing enhanced geothermal system at bongor basin, chad

In this paper, the feasibility of power generation from an enhanced geothermal system (EGS) located beneath an oilfield at the Bongor basin in Chad was examined through the analysis of numerical simulation parameters. A 3D geometric model is constructed to represent the proposed EGS and a thermo-hydro-mechanical (THM) coupled mathematical model was used in the simulation process to link all inter-dependent parameters of heat mining. Oilfield warm water is anticipated to be the circulating fluid of the thermal reservoir due to its ready availability from high water-cut oil wells. Chad depends heavily on a diesel power plant, thus this work further proposes the utilization of carbon dioxide (CO2) from the power plants to be used as heat mining fluid and likely CO2 sequestration into deep granite formation. The results indicate that the implementation of EGS beneath the current oilfield would have significant advantages both technically, environmentally, and economically. Oilfield produced water at warm temperatures improved heat mining efficiency and utilization of oilfield water in geothermal wells will reduce costs involved in water treatment and disposal. The geothermal gradient is sufficient to produce water at a higher temperature that can be utilized commercially by different binary power plants. Utilizing CO2 as heat extraction fluid showed significant heat extraction, higher than using oilfield produced water. Furthermore, substantial amount of CO2 can be deposited into the formation, thus reducing emission of greenhouse gasses to the atmosphere.

Adjoint-based inversion for porosity in shallow reservoirs using pseudo-transient solvers for non-linear hydro-mechanical processes

Porous flow is of major importance in the shallow subsurface, since it directly impacts on reservoir-scale processes such as waste fluid sequestration or oil and gas exploration. Coupled and non-linear hydro-mechanical processes describe the motion of a low-viscous fluid interacting with a higher viscous porous rock matrix. This two-phase flow may trigger the initiation of solitary waves of porosity, further developing into vertical high-porosity pipes or chimneys. These preferred fluid escape features may lead to localised and fast vertical flow pathways potentially problematic in the case of for instance CO2 sequestration. Constraining the porosity and the non-linearly related permeability distribution in such environments is a major challenge. Although seismic imaging methods accurately localise the high-porosity chimneys in the inverted wave-speed field, the conversion to porosity is not straightforward. We develop an inversion framework to reconstruct the unknown porosity field using relevant observable quantities such as subsurface fluid fluxes. We introduce the adjoint framework for the two-phase flow equations, which allows for efficient calculations of the pointwise gradients of the flow solution with respect to the porosity. We then use the gradients in a gradient descent method to invert for the pointwise porosity. We solve the forward and the adjoint equations using an iterative matrix-free pseudo-transient approach with the finite difference method. The proposed parallel solving procedure executes optimally on the latest many-core hardware accelerators such as GPUs. Numerical results show that an inversion for porosity is challenging if data is sparse since the porosity is very locally sensitive to the fluid flux. We introduce the concepts of sensitivity kernels as employed in seismology for the set of two-phase equations and suggest this approach as a standard for future studies.

Large-scale gas accumulation mechanisms and reservoir-forming geological effects in sandstones of Central and Western China

Large-scale gas accumulation areas in large oil-gas basins in central and Western China have multiple special accumulation mechanisms and different accumulation effects. Based on the geological theory and method of natural gas reservoir formation, this study examined the regional geological and structural background, formation burial evolution, basic characteristics of gas reservoirs, and fluid geology and geochemistry of typical petroliferous basins. The results show that the geological processes such as structural pumping, mudstone water absorption, water-soluble gas degasification and fluid sequestration caused by uplift and denudation since Himalayan stage all can form large-scale gas accumulation and different geological effects of gas accumulation. For example, the large-scale structural pumping effect and fluid sequestration effect are conducive to the occurrence of regional ultra-high pressure fluid and the formation of large-scale ultra-high pressure gas field; mudstone water absorption effect in the formation with low thickness ratio of sandstone to formation is conducive to the development of regional low-pressure and water free gas reservoir; the water-soluble gas degasification effect in large-scale thick sandstone can not only form large-scale natural gas accumulation; moreover, the degasification of water-soluble gas produced by the lateral migration of formation water will produce regional and regular isotopic fractionation effect of natural gas, that is, the farther the migration distance of water-soluble gas is, the heavier the carbon isotopic composition of methane formed by the accumulation.

Endovascular Treatment in a Case of Phelgmasia Cerulean Doleans

Background: Phlegmasia cerulean dolens (PCD) is an uncommon and severe manifestation of massive proximal venous thrombosis of the lower extremities associated with a high degree of morbidity and mortality. Case: We describe a case of a 67-year-old gentleman with metastatic gastric neuroendocrine tumour, who developed PCD of his left lower limb. He underwent endovascular thrombectomy with thrombolysis and stent placement with good effect. Discussion: Characterised by severe venous outflow obstruction, marked limb swelling, pain and discolouration, PCD can lead to venous gangrene, congestion with massive fluid sequestration and circulatory collapse if left untreated. Various treatment modalities were reported with varying outcomes, morbidity and mortality. Conclusion: A multifaceted approach to PCD may be required for successful limb salvage, taking into account the risks and benefits of each treatment modality.

Su1428 – Does Intracellular Fluid Shift Contribute to Fluid Sequestration and Intravascular Fluid Deficit in Acute Pancreatitis?

Su1428 – Does Intracellular Fluid Shift Contribute to Fluid Sequestration and Intravascular Fluid Deficit in Acute Pancreatitis?

Acute abdominal compartment syndrome in a severely burned patient: Lack of colloid fluid availability in acute resuscitation may play a role

We report on a case in which a 27-year-old male patient sustained a significant burn injury requiring admission to the intensive care unit, with respiratory support and close haemodynamic monitoring. Owing to a lack of colloid resuscitation fluids, crystalloid fluids were used exclusively. The volume of fluid required to maintain an adequate urine output also resulted in fluid sequestration in other body compartments, eventually resulting in abdominal compartment syndrome. We believe this life-threatening complication could have been avoided had colloids been available

Fluid sequestration is a useful parameter in the early identification of severe disease of acute pancreatitis.

Early identification of severe disease of acute pancreatitis (AP) is of critical importance to improve the prognosis. Fluid sequestration (FS), calculated from administrated fluid and fluid output, is a simple prognostic parameter. We examined its utility in the early phase of AP. We retrospectively investigated AP patients between January 2009 and April 2017. We compared FS in the first 24h (FS24) with FS in the first 48h (FS48) and administrated fluid volume within the first 24h (FV24). Diagnostic yield for predicting intensive care unit (ICU) admission and persistent organ failure (POF) was assessed using receiver operating characteristic curves. We also evaluated risk factors for developing severe disease of AP. A total of 400 AP patients were included in the analysis (median age 64years; male 60%). According to the Japanese severity criteria, 158 patients (40%) were diagnosed as severe disease. The rates of mortality, ICU admission and POF were 0.8%, 4.5% and 7.3%, respectively. FS24 showed a similar predictive accuracy in comparison with FS48 and was superior to FV24 in predicting ICU admission and POF. FS24 ≥ 1.6L, male sex, presence of systemic inflammatory response syndrome and computed tomography severity index ≥ 3 on admission were independent risk factors for disease progression in AP in the multivariate analysis. FS24 was a simple and easily calculated parameter with high predictive accuracy for discriminating patients who needed intensive care. Patients with FS24 ≥ 1.6L had an increased risk of developing severe disease.

Variability of the f-cell ratio after treatment of traumatic hemorrhagic shock

PurposeMeasuring total blood volume (TBV) in critically ill patients, using isotope techniques to determine red cell volume (RBCV) and plasma volume (PV) is laborious. Recently, PV measurement using a single bolus dose of tracers has been validated, thus, allowing TBV calculation using large venous hematocrit (LVHCT). However, this technique relies on using a correlation factor, the f-cell ratio, to adjust for differences in LVHCT and total body hematocrit (TBHCT). The normal f-cell ratio is 0.9 but has never been studied in patients recovering from hemorrhagic shock (HS). This study assesses the f-cell ratio at different phases after HS to determine accuracy in calculating TBV.Methods114 injured patients requiring immediate operation for HS were studied. All patients had measurements of PV and RBCV via isotope dilution enabling measurements of TBHCT. Correlation of LVHCT and TBHCT were used to calculate the f-cell ratio in the fluid sequestration (n = 81) and in the fluid mobilization period (n = 108).ResultsThe f-cell ratio (mean ± SD) averaged 0.89 ± 0.15 and 0.90 ± 0.01 in the first and second halves of the fluid sequestration period versus 0.90 ± 0.2 and 0.80 ± 0.07 in the first and second 48 h of the fluid mobilization period. The f-cell ratio was significantly lower (p=<0.001) in the mobilization period.ConclusionsThese data show for the first time that using PV and LVHCT to calculate TBV after HS is unreliable. The mechanisms causing this variation in f-cell ratio is unknown but likely related to capillary/interstitial dynamics and needs further scientific study.

The utility of neutrophil to lymphocyte ratio and fluid sequestration as an early predictor of severe acute pancreatitis

It is important to identify the patients with high-risk progression to develop severe acute pancreatitis (SAP). The study was to assess whether neutrophil to lymphocyte ratio (NLR) and fluid sequestration (FS) could represent useful markers for predicting the severity. A total of 1639 patients who underwent clinical diagnosis of AP was performed. Various serologic and clinical parameters on admission were investigated. Chronologic change in NLR and FS were analyzed, and theirs utility for predicting severity of AP was evaluated by receiver operator characteristic (ROC) curve analysis. Correlation analysis was assessed by Spearman’s rank test. NLR and FS levels were both increased significantly in SAP and positively correlated with Ranson score and hospital stays. The ROC curve analyses showed the optimal cut-off values of NLR for admission with day0, day1, day2 were 9.64, 6.66 and 6.50, giving sensitivity of 77–82%. The optimal cut-off values of FS for admission with day1, day2, day3 were 1375 ml, 2345 ml and 3424 ml, giving sensitivity of 62–75%. Moreover, measurement of NLR and FS together exhibited a similar area under curve (AUC) and sensitivity for SAP prediction compared with the those of Ranson score. Increase of NLR and FS are correlated with severity and can be suggested as a predictive factor in an early stage of AP.

Ileus and Obstruction in the Surgical Critical Care Patient

Gastrointestinal dysfunction is a common occurrence in the critically ill surgical patient as both a contributor to disease progression and a consequence of critical illness. Failure of motility may ultimately progress to obstruction, either functional (e.g., paralytic ileus) or mechanical (e.g., small bowel obstruction). Obstruction leads to bowel distention, fluid sequestration in the lumen and wall of the bowel, alterations in mucosal integrity, and bacterial overgrowth, which results in not only local bowel ischemia but also distant organ damage due to the release of inflammatory cytokines. Although postoperative ileus is a common condition, in the critically ill patient, it may signify a serious complication such as anastomotic leak or sepsis; therefore, management is directed toward identification and treatment of the underlying cause. Regarding small bowel obstruction (SBO), management hinges on whether or not the bowel is strangulated, and the need for operation should be addressed at every step of the evaluation. Although most patients are successfully treated without operation, SBO is a surgical disease, a fact underscored by the improved outcomes seen in patients admitted to a surgical service. Large bowel obstruction is a surgical emergency that requires prompt decompression either by colonoscopy or surgery. Regardless of the etiology of gastrointestinal dysfunction, emergency surgery is required in patients with signs of bowel strangulation or perforation such as tachycardia, peritonitis, fever, or leukocytosis. Key words: acute colonic pseudo-obstruction, adhesive small bowel disease, ileus, large bowel obstruction, Ogilvie syndrome, small bowel obstruction bowel perforation, volvulus

Simple and rapid quantification of vancomycin in serum, urine and peritoneal/pleural effusion via UHPLC–MS/MS applicable to personalized antibiotic dosing research

Management of the therapy of life-threatening bacterial infection is extremely based on an optimal antibiotic treatment. Achieving the correct vancomycin dosage in blood and target tissues can be complicated in special situations, e.g., where large fluid sequestration and/or acute renal failure occur.A UHPLC–MS/MS method operating in electrospray (ESI) positive ion mode was applied for the determination of vancomycin in serum, urine and peritoneal/pleural effusion. Sample pretreatment was composed of dilution and simple protein precipitation where only a small volume (50μL) of serum, urine or peritoneal/pleural effusion was required. The separation of vancomycin was performed on a Meteoric Core C18 BIO column (100×4.6mm, 2.7μm) by gradient elution with 0.1% formic acid in water and acetonitrile. The total time of analysis was 4.5min. The method was found to be linear in the range of 2–60μM (or 0.5–10μM) for serum, 0.27–10μM (or 2–60μM) for peritoneal/pleural effusion and 25–300μM for urine, which was adequate for the determination of vancomycin in patient samples. The intra- and inter-day precision was below 8% RSD, and accuracy was from 89 to 104%.The UHPLC/MS–MS method offers a fast and reliable approach to determine vancomycin concentrations in three different human body fluid samples (serum, urine and peritoneal/pleural effusion) with a simple sample pretreatment that was the same for all selected specimens. This method should be applicable to large sample series in clinical (pharmacokinetic/pharmacodynamic) studies.