Development of Keshen ultra-deep and ultra-high pressure gas reservoirs in the Kuqa foreland basin, Tarim Basin: Understanding and technical countermeasures

The Keshen Gas Field in the Kuqa foreland basin, Tarim Basin, is a rare fractured tight sandstone gas reservoir with ultra-depth and ultra-high pressure. During its pilot period of gas field development, the development effect is poor with a low development well success rate, a low utilization rate of production capacity and a rapid decline of gas well productivity. In view of these problems, development experiments and technological researches were carried out continuously after the geological characteristics of gas reservoirs, productivity control factors, reservoir connectivity, seepage characteristics, gas and water relations and water invasion laws were studied thoroughly. And consequently, the development countermeasures of “well placement in high position, moderate stimulation and early-stage drainage” were prepared, and five matching development technologies were formed, such as description technology of ultra-deep complex structures, well pattern optimization technology for fractured tight sandstone gas reservoirs, fracture net acid fracturing technology for fractured tight sandstone reservoirs, dynamic monitoring technology for ultra-deep and ultra-high pressure gas wells, wellbore integrity management and evaluation technology for high pressure gas wells. The following remarkable application results were achieved in the process of gas field development. First, the drilling depth error of the target formation drops from 125 m to less than 30 m. Second, the utilization rate of production capacity in the Keshen 8 Block reaches 100%. Third, the average absolute open flow rate is increased by 5 times to 273 × 104 m3/d from 50 × 104 m3/d before the stimulation. Fourth, safe and smooth production under high temperature and high pressure conditions is realized in the Keshen Gas Field. In conclusion, the successful and efficient development of the Keshen Gas Field provides experiences for the development of similar gas reservoirs at home and abroad, and its development countermeasures and matching technologies have important guidance and reference significance. Keywords: Tarim basin, Keshen gas field, Cretaceous, Bashijiqike Fm, Ultra-deep, Ultra-high pressure, High temperature, Fractured, Tight sandstone gas reservoir, Development technologies and countermeasur

HAT therapy for sepsis: A review of the therapeutic rationale and current clinical evaluation status

Vitamin C-based cluster therapy, which involves the combined application of hydrocortisone, vitamin C, and thiamine (HAT), is a recently proposed new treatment option for sepsis on top of conventional treatment. This therapy has a strong theoretical basis, but its clinical efficacy remains inconclusive. This review summarizes the rationale for HAT therapy for sepsis and describes the evaluation of its efficacy in clinical observational studies and randomized controlled trials, with the aim of providing a reference for the future clinical practice application of HAT therapy in sepsis

Intestinal Microbiota in Sepsis

Abstract Sepsis is defined as a life-threatening organ dysfunction, which is caused by a dysregulated host response to infection. The composition of the intestinal microbiota is significantly different between patients with sepsis and healthy individuals. Intestinal microbial imbalance plays an important role in the occurrence and development of sepsis. Our review mainly introduces the mechanism of intestinal microbiota involvement in sepsis, the effects of microbiota dysbiosis on the damage of multiple organs and concisely discusses the prospects for microbe-specific treatment of sepsis in the future

Detecting Leaks and Sensor Biases by Recursive Identification with Forgetting Factors

In industrial processes, pipes and tanks may leak and sensors may have biases since corrosion, measuring noises and instrument faults exist. In order to maintain production in normal and safe conditions, detecting possible faults of production equipment on time is crucial. In this paper, a process model is proposed to describe boiler tube leak problem. Based on this model, least-squares methods with constant and timevarying forgetting factors are presented to detect the leakage and sensor bias. The application in a boiler system shows that the proposed methods can detect the boiler tube leakage more effectively than the method without forgetting factors

Association of preadmission metformin use and mortality in patients with sepsis and diabetes mellitus: a systematic review and meta-analysis of cohort studies

Abstract Background Recent studies have reported that preadmission metformin users had lower mortality than non-metformin users in patients with sepsis and diabetes mellitus; however, these results are still controversial. Therefore, we conducted a systematic review and meta-analysis of published observational cohort data to determine the association between preadmission metformin use and mortality in septic adult patients with diabetes mellitus. Methods The MEDLINE, EMBASE, and Cochrane CENTRAL databases were searched from their inception to September 30, 2018. Cohort studies that evaluated the use of metformin in septic adult patients with diabetes mellitus were included. The quality of outcomes was evaluated using the Newcastle-Ottawa Scale (NOS). The inverse variance method with random effects modelling was used to calculate the pooled odds ratios (ORs) and 95% CIs. Results Five observational cohort studies (1282 patients) that were all judged as having a low risk of bias were included. In this meta-analysis, metformin use was associated with a significantly lower mortality rate (OR, 0.59; 95% CI, 0.43–0.79, P = 0.001). Conclusions This meta-analysis indicated an association between metformin use prior to admission and lower mortality in septic adult patients with diabetes mellitus. This finding suggested that the possible effect of metformin should be evaluated in future clinical trials

Reservoir controlling differences between consequent faults and antithetic faults in slope area outside of source: A case study of the south-central Wenan slope of Jizhong Depression, Bohai Bay Basin, East China

The control effects of different occurrence faults on oil and gas accumulation and distribution in the outer slope area of oil and gas reservoirs were studied taking the south-central Wen'an slope of the Jizhong depression in the Bohai Bay Basin as an example. Based on 3D seismic data and the distribution of oil and water, the controlling differences between consequent fault and antithetic fault were analyzed and compared from the formation and evolution rule of faults and the formation mechanism of fault traps, including development positions of the consequent fault traps and antithetic fault traps, oil and gas distribution horizon adjusted by fault and formation period of fault traps. The differences between consequent faults and antithetic faults in controlling reservoirs have three main aspects: (1) Consequent fault traps and antithetic fault traps are in different positions, the consequent fault traps are at the segmented growing point in the hanging wall of “hard-linkage” faults, while the antithetic fault traps are developed in the position with the largest throw in the footwall because of tilting action; (2) The two kinds of faults result in different oil and gas distribution vertically, oil and gas adjusted by consequent faults is distributed in a single layer or multi-layers, while oil and gas adjusted by antithetic faults occur in single layers; (3) The two kinds of fault traps are formed in different periods, the consequent fault traps are formed at the time when the related faults enter the stage of “hard-linkage”, while the antithetic fault traps are formed at the beginning of the fault active period. Key words: Bohai Bay Basin, Jizhong depression, slope area outside of source, consequent fault, antithetic fault, fault trap, transverse anticline, fault controlling hydrocarbon accumulatio

Drought Variations in the Yili Basin, Northwest China since AD 1673 Based on Tree-Ring Width

The Yili Basin represents a typical region influenced by the Westerlies, and as a result of the substantial precipitation delivered by these winds, it has emerged as a significant hub for agricultural and animal husbandry activities in Central Asia. This study established a 419-year tree-ring width chronology, utilizing living Picea schrenkiana samples from two sampling sites in the Yili Basin. Correlation analysis showed that the standard tree-ring width chronology had the best correlation with the Palmer Drought Severity Index from the previous August to the current May (PDSIP8C5) (r = 0.614, n = 59, p P8C5 variations from 1673 to 2018. The reconstruction results reveal eight wet and seven dry periods during the past 346 years. In the reconstructed series, droughts are particularly pronounced around 1770 and 1920, and the PDSI shows a significant long-term wetting trend since the 1980s. The solar activity, North Atlantic Oscillation (NAO), and Atlantic Multidecadal Oscillation (AMO) jointly influenced the regional moisture variation