How to Choose the Suitable Steel of Wellhead, Wellbore, and Downhole Tools for Acid Gas Reinjection Flooding

The material selection of injection gas wells in acid gas flooding is the bottleneck of the successful implementation of the technical scheme. Through standard and literature research, the materials of the wellhead, wellbore, and packer for reinjection well in acid gas flooding are preliminarily established, and then the suitable materials are further screened by using the weight-loss and surface characterization method. Finally, a new type of packer is designed to optimize the wellbore material. The results show that 35CrMo (CR = 0.0589 mm/y) steel is used for wellhead materials, 625 alloy steel is selected as the sealing surface, and 625 or 825 alloys (with CR ≤ 0.0055 mm/y) steel is used for wellhead sealing material. The main material of the packer is 718 Alloy (with CR ≤ 0.0021 mm/y). The cost of T95 steel within 20 years (1263 ten thousand yuan) of service is much smaller than that of G3 alloy (1771 ten thousand yuan), but after 30 years of service, its cost is close to that of G3 alloy. A kind of downhole packer for acid gas reinjection is designed. Among them, G3 alloy steel tubing is used between the packer and the relief valve, T95 steel tubing is selected above the packer and below the safety valve, and the packer is set in the G3 steel tubing. The serious pitting corrosion of T95 steel in the liquid phase environment is due to the uneven deposition of FeS and FeCO3 on the steel surface

Parameter optimization of acid fracturing in ultra-deep fault zone carbonate reservoir

The characteristics of fracture development are complex in Shunbei area. The natural fracture development is different between different fault zones and in different locations of the same fault zone. Not all natural fractures can be activated during acid fracturing, and not all natural fractures can contribute to well productivity after acid fracturing. The use of natural fractures can not only improve the seepage capacity of the reservoir, but also improve the well productivity. Therefore, the influence of artificial fracture on the opening and fracture conductivity maintenance of natural fracture is studied, and finally the acid fracturing roceand parameters based on the change of natural fracture are formed

Optimal configuration of P2H in the park integrated energy system considering natural gas mixed with hydrogen

The technology of power to hydrogen (P2H) and natural gas mixed hydrogen is highly regarded in theoretical research and engineering application in promoting the consumption of renewable energy and reducing carbon emissions. Targeting the park integrated energy system with high proportion renewable energy, an optimal configuration method of P2H considering natural gas mixed with hydrogen and cross seasonal storage is proposed. Firstly, the operational framework and energy flow relationship of the park integrated energy system are sorted out, and the mathematical models for the internal energy production, conversion, and storage equipment in the park are established. Secondly, a configuration model of P2H is established with the goal of optimizing the annual investment cost of equipment, the annual operating cost, and the carbon trading cost. Finally, the effectiveness of the proposed model is verified by an example analysis. The impact of changes in investment cost of electrolytic cells, the upper limit of mixed hydrogen volume fraction and cost weight coefficients of economy and low-carbon on the planned operation results are analyzed. The simulation results show that the proposed model can effectively improve the absorption capacity of renewable energy and reduce the overall economic cost and carbon emissions

The Application of Software “Rapid Processing of Perfusion and Diffusion” in Acute Ischemic Stroke

In the event of an acute ischemic stroke, saving the penumbra is the most important aspect of early treatment. The rapid and accurate identification of ischemic penumbra plays a key role in its comprehensive treatment. At present, the identification method and evaluation standard of ischemic penumbra have not been unified. Numerous pieces of software identifying ischemic penumbra have been developed, such as rapid processing of perfusion and diffusion (RAPID), Sphere, Vitrea, and computed tomography perfusion+ (CTP+). The RAPID software, analyzing and integrating multi-mode image data (mainly based on perfusion weighted imaging (PWI) or computed tomography perfusion (CTP) images, shows good performance in identifying ischemic penumbra and has been utilized for the assessment of ischemic penumbra in many ischemic stroke clinical studies, achieving good outcomes and promoting the transition from “time window” to “tissue window” in the treatment of early stage AIS. To obtain a comprehensive understanding of the RAPID software and its accuracy in evaluating ischemic penumbra, this paper reviews the background and development of the RAPID software, summarizes the published acute cerebral infarction trials using the RAPID software, generalizes the threshold parameters in different time windows, and further discusses its application and limitations

Hybrid surgery can improve neurocognitive function in patients with internal carotid artery occlusion

Abstract Internal carotid artery occlusion (ICAO) is a relatively uncommon but important cause of transient ischaemic attack and cerebral infarction. Hybrid surgery (HS) improves cerebral perfusion, but its impact on neurocognitive function has been controversial. Patients with symptomatic chronic ICAO treated by hybrid surgery or medical treatment from 2016 to 2019 were included. We recorded and analysed the clinical characteristics, angiographic data, outcomes and cognitive status. Functional assessments, including the National Institutes of Health Stroke Scale (NIHSS), the Barthel Index, and a battery of neuropsychological tests, including the Mini-Mental State Examination (MMSE), Alzheimer Disease Assessment Scale–Cognitive Subtest (ADAS-cog), verbal fluency, and Colour Trail test Parts 1 and 2, were administered. Significant improvements in the ADAS (before, 7.5 ± 6.2 versus after, 5.2 ± 5.7; P = 0.022), MMSE (before, 25.5 ± 2.8 versus after, 28.1 ± 2.3; P = 0.013), and Colour Trail test Part 1 (before, 118.3 ± 26.5 versus after, 96.2 ± 23.1; P = 0.016) were observed six months after HS. Moreover, the abovementioned postprocedure scales were ameliorated in the HS group. This study found that in patients with multiple symptomatic ICAO and objective ipsilateral ischaemia, successful HS leads to improvement in the scores of three cognitive tests

Tubeless versus standard percutaneous nephrolithotomy: an update meta-analysis

Abstract Background To update a previously published systematic review and meta-analysis on the efficacy and safety of tubeless percutaneous nephrolithotomy (PCNL). Methods A systematic literature search of EMBASE, PubMed, Web of Science, and the Cochrane Library was performed to confirm relevant studies. The scientific literature was screened in accordance with the predetermined inclusion and exclusion criteria. After quality assessment and data extraction from the eligible studies, a meta-analysis was conducted using Stata SE 12.0. Results Fourteen randomized controlled trials (RCTs) involving 1148 patients were included. Combined results demonstrated that tubeless PCNL was significantly associated with shorter operative time (weighted mean difference [WMD], −3.79 min; 95% confidence interval [CI], −6.73 to −0.85; P = 0.012; I2 = 53.8%), shorter hospital stay (WMD, −1.27 days; 95% CI, −1.65 to −0.90; P < 0.001; I2 = 98.7%), faster time to return to normal activity (WMD, −4.24 days; 95% CI, −5.76 to −2.71; P < 0.001; I2 = 97.5%), lower postoperative pain scores (WMD, −16.55 mm; 95% CI, −21.60 to −11.50; P < 0.001; I2 = 95.7%), less postoperative analgesia requirements (standard mean difference, −1.09 mg; 95% CI, −1.35 to −0.84; P < 0.001; I2 = 46.8%), and lower urine leakage (Relative risk [RR], 0.30; 95% CI 0.15 to 0.59; P = 0.001; I2 = 41.2%). There were no significant differences in postoperative hemoglobin reduction (WMD, −0.02 g/dL; 95% CI, −0.04 to 0.01; P = 0.172; I2 = 41.5%), stone-free rate (RR, 1.01; 95% CI, 0.97 to 1.05; P = 0.776; I2 = 0.0%), postoperative fever rate (RR, 1.05; 95% CI, 0.57 to 1.93; P = 0.867; I2 = 0.0%), or blood transfusion rate (RR, 0.79; 95% CI, 0.36 to 1.70; P = 0.538; I2 = 0.0%). The results of subgroup analysis were consistent with the overall findings. The sensitivity analysis indicated that most results remained constant when total tubeless or partial tubeless or mini-PCNL studies were excluded respectively. Conclusions Tubeless PCNL is an available and safe option in carefully evaluated and selected patients. It is significantly associated with the advantages of shorter hospital stay, shorter time to return to normal activity, lower postoperative pain scores, less analgesia requirement, and reduced urine leakage