Investigating the Effect of Varying Tubing Air Concentration during the Descaling of Petroleum Production Tubing using Multiple High-Pressure Nozzles

Despite the continued research effort on erosion behaviour of multiple flat fan nozzles in removing different types of scale deposits from petroleum production tubing, effect of chamber air concentration and nozzles configuration is yet to be given detail consideration. This study, therefore, considers the utilization of multiple high-pressure sprays at different chamber air concentration to enhance the rate of scale removal from petroleum production tubing. Additionally, options of altering chamber air/water ratio and header configurations for more effective scale removal were explored. So also, the relationship of nozzle header arrangement towards the removal of paraffin of different stages of deposition in petroleum production tubing have been studied. Consequently, theselection of chamber air concentration and header configuration (nozzles arrangement) for effective scale removal was found to be governed by the shape and type of the scale deposit. More so, the descaling capacity increases with decrease in number of nozzlesdue to pressure drop effect irrespective of the type or shape of the scale deposit. This novel descaling experiment of utilising 10 MPa injection pressure from 25 mm jetting position averagely removes hollow paraffin deposits that ranges from 44 to 280 g and 34 to 89g of solid shaped paraffin as a result of altering nozzles configuration. Correspondingly, an average removal difference ranging from 48 to 270 g of hollow shaped and 35 to 218 g of solid shaped paraffin depositwas recorded as a result of compressing the chamber pressure by 0.2 MPa and subsequently suctioning it by -0.008 MPa respectively

Investigating the Impact of Non-Hydrodynamically Connected Descaling Parameters in the Removal of Different Stages of Paraffin Deposits Using Multiple Nozzles in Petroleum Production Tubing

Despite the continued research efforts in understanding the erosional behaviors of multiple flat fan nozzles in the removal of different types of scale deposits from petroleum production tubing. The non-hydrodynamically connected descaling parameters such as stand-off distance, nozzle arrangement and chamber pressure have not been duly considered up to date. This research utilizes 3-flat fan high-pressure nozzles at a high injection pressure of 10 MPa to remove paraffin deposits at different growth stages from petroleum production tubing to evaluate the effects of the descaling parameters on scale removal. A stand-off distance of 25 mm, 50 mm and 75 mm; nozzle arrangement in novel orientations (triangle, diagonal & right-angle) involving 7-nozzles header and chamber pressures (in compression – 0.2 MPa and vacuum -8.0 x10-3 MPa) were utilized as the varying non-hydrodynamically connected parameters. Generally, the selection of both nozzle arrangement and chamber air concentration was found to be governed by the type and shape of the deposit in question while the scale removal capability was found to be reduced with an increase in stand-off distance due to poor jet contact. An average hollow shaped paraffin removal of 276 g, 259 g and 226 g were recorded at ambient condition across the respective stand-off distance of the three respective nozzles arrangements. While the introduction of 0.2 MPa compressed air significantly increased the respective removal of the early stage paraffin deposition to 342 g, 299 g and 277 g respectively. Also, more hollow shaped removal improvement of 366 g, 320 g and 288 g were achieved after suctioning the chamber by -0.008 MPa, while simultaneously pumping water at 10 MPa. The case of solid shaped paraffin signifying complete tubing blockage was not effective at ambient condition, with average paraffin removal of 99 g, 126 g and 112 g respectively. However, the introduction of compressed chamber air registered the best solid paraffin removal results of 235 g, 286 g and 256 g respectively. Whereas the suction operation recorded an average removal of 229 g, 270 g and 250 g of paraffin across the respective jet positions and nozzle configurations. This result provides a practical approach to the removal of organic scales deposits at varying descaling conditions of injection pressure, standoff distance and nozzle arrangement

Solubility trapping as a potential secondary mechanism for CO2 sequestration during enhanced gas recovery by CO2 injection in conventional natural gas reservoirs : an experimental approach

This study aims to experimentally investigate the potential of solubility trapping mechanism in increasing CO2 storage during EGR by CO2 injection and sequestration in conventional natural gas reservoirs. A laboratory core flooding process was carried out to simulate EGR on a sandstone core at 0, 5, 10 wt% NaCl formation water salinity at 1300 psig, 50 °C and 0.3 ml/min injection rate. The results show that CO2 storage capacity was improved significantly when solubility trapping was considered. Lower connate water salinities (0 and 5 wt%) showed higher CO2 solubility from IFT measurements. With 10% connate water salinity, the highest accumulation of the CO2 in the reservoir was realised with about 63% of the total CO2 injected stored; an indication of improved storage capacity. Therefore, solubility trapping can potentially increase the CO2 storage capacity of the gas reservoir by serving as a secondary trapping mechanism in addition to the primary structural and stratigraphic trapping and improving CH4 recovery

Results of the COVID-19 mental health international for the general population (COMET-G) study.

INTRODUCTION: There are few published empirical data on the effects of COVID-19 on mental health, and until now, there is no large international study. MATERIAL AND METHODS: During the COVID-19 pandemic, an online questionnaire gathered data from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively. STATISTICAL ANALYSIS: Descriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses and Factorial Analysis of Variance (ANOVA) tested relations among variables. RESULTS: Probable depression was detected in 17.80% and distress in 16.71%. A significant percentage reported a deterioration in mental state, family dynamics and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (31.82% vs. 13.07%). At least half of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop depression was associated with history of Bipolar disorder and self-harm/attempts (RR = 5.88). Suicidality was not increased in persons without a history of any mental disorder. Based on these results a model was developed. CONCLUSIONS: The final model revealed multiple vulnerabilities and an interplay leading from simple anxiety to probable depression and suicidality through distress. This could be of practical utility since many of these factors are modifiable. Future research and interventions should specifically focus on them

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Network layer for cognitive radio sensor networks

Based on recent trends, Cognitive Radio paradigm has become an integral part of future communication networks of which Wireless Sensor Network is an integral part. However, Cognitive Radio (CR) introduces critical issues that have to be addressed for communication in networks to be achieved. Routing, being the core of communication, has to be critically examined within the context of Cognitive Radio Sensor Networks. In this chapter, the authors discuss relevant issues on the topic of routing in Cognitive Radio Sensor Networks (CRSN). As a basis, a general overview of routing in the Wireless Sensor Network (WSN) is made. The applicability of these protocols in CRSN is discussed and the need for integrating Opportunistic Spectrum Access components into existing Wireless Sensor Network protocols is exposed. Factors affecting routing in CRSN are outlined with an emphasis on a cross layering design approach based on a generalized framework. Recent works in this respect are categorized, and finally, open issues in need for research attention are pinpointed

Anxiety, depression and stress among internally displaced persons and host community in an armed conflict region: A comparative study.

This study compares the psychological profile of Internally Displaced Persons (IDPs) and individuals living in host communities in the war-affected setting. We conducted a cross-sectional survey from October-November 2019. Subjects were recruited from six IDPs camps and the surrounding host communities within the metropolis of Maiduguri, Nigeria by convenience sampling. Data were collected using the Hausa version of Depression Anxiety Stress Scale-21, and analysed by logistic regression using adjusted odds ratio (AOR) at 95% Confidence Interval (CI). A total of 562 subjects were recruited. Living in IDP camp was the most significantly predictor of depression, anxiety, and stress. The common predictors were living in an IDP camp, and marital status (separated). Aged 18-29years was a protective factor compared to those ≥50years. Living in IDP camps, separated from partners, lack of education and pre-conflict employment were significant predictors of depression, anxiety and stress

Anxiety, depression and stress among internally displaced persons and host community in an armed conflict region: a comparative study

This study compares the psychological profile of Internally Displaced Persons (IDPs) and individuals living in host communities in the war-affected setting. We conducted a cross-sectional survey from October-November 2019. Subjects were recruited from six IDPs camps and the surrounding host communities within the metropolis of Maiduguri, Nigeria by convenience sampling. Data were collected using the Hausa version of Depression Anxiety Stress Scale-21, and analysed by logistic regression using adjusted odds ratio (AOR) at 95% Confidence Interval (CI). A total of 562 subjects were recruited. Living in IDP camp was the most significantly predictor of depression, anxiety, and stress. The common predictors were living in an IDP camp, and marital status (separated). Aged 18-29years was a protective factor compared to those ≥50years. Living in IDP camps, separated from partners, lack of education and pre-conflict employment were significant predictors of depression, anxiety and stress

Enhanced gas recovery by nitrogen injection : the effects of injection velocity during natural gas displacement in consolidated rocks

The choice of the flow velocity in EGR thus becomes important since higher injection rates could lead to premature mixing of the fluids and lower injection rates generally provide longer resident times for the fluids in contact and indirectly increases the mixing of the gases. Additionally, the medium peclet numbers mostly indicate the best injection rates that translate to a smoother displacement with a lower dispersion coefficient during the EGR process. Therefore, N2 Injection into natural gas reservoirs offers the potential to higher recovery efficiency with less mixing compared to conventional CO2 injection. The atmospheric air contained 79% of N2, making it readily available than CO2 with 400 ppm air composition. More so, N2 requires less compression ratio, which is why a lower amount of it was required to initiate much pressure in the CH4 reservoir during displacement. These made the use of N2 more economically feasible and friendly for the EGR process. A laboratory core flooding experiment was carried out to simulate the effect of injection velocity on CH4 recovery and dispersion coefficient. This was done at 40 ◦C, 1500 psig, and 0.2–1.0 ml/min injection rates. The results showed that a medium peclet number could be used to predict the best injection rate that translates to a smoother displacement with a lower dispersion coefficient during the EGR process. CH4 recovery and efficiency were highest at lower injection velocities experienced in both core samples. This could be attributed to insignificance nascent mixing observed as seen on their recorded low longitudinal dispersion coefficient results. Consequence, the experimental runs at high injection rates (0.6–1.0 ml/min) present a different scenario with lower recovery and efficiency due to their high interstitial velocities as the N2 plumes transverses into the core sample during CH4 displacement. Overall, the least methane production and efficiency were noticed in the Bandera core sample as a result of the heterogeneity effect due to the presence of higher clay contents in Bandera than Berea gray. When the capillary forces within the narrower pores in Bandera core sample were overcome, the clay particles occupied those pores thereby sealing some of the flow paths within the pore matrix. This reduces the flow channels, significantly, through which the injected N2 will flow to displace the residual CH4

The effect of different degrees of lockdown and self-identified gender on anxiety, depression and suicidality during the COVID-19 pandemic: Data from the international COMET-G study.

INTRODUCTION: During the COVID-19 pandemic various degrees of lockdown were applied by countries around the world. It is considered that such measures have an adverse effect on mental health but the relationship of measure intensity with the mental health effect has not been thoroughly studied. Here we report data from the larger COMET-G study pertaining to this question. MATERIAL AND METHODS: During the COVID-19 pandemic, data were gathered with an online questionnaire from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Anxiety was measured with the STAI, depression with the CES-D and suicidality with the RASS. Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively. STATISTICAL ANALYSIS: It included the calculation of Relative Risk (RR), Factorial ANOVA and Multiple backwards stepwise linear regression analysis RESULTS: Approximately two-thirds were currently living under significant restrictions due to lockdown. For both males and females the risk to develop clinical depression correlated significantly with each and every level of increasing lockdown degree (RR 1.72 and 1.90 respectively). The combined lockdown and psychiatric history increased RR to 6.88 The overall relationship of lockdown with severity of depression, though significant was small. CONCLUSIONS: The current study is the first which reports an almost linear relationship between lockdown degree and effect in mental health. Our findings, support previous suggestions concerning the need for a proactive targeted intervention to protect mental health more specifically in vulnerable groups