Oil Displacement Efficiency and Performance Evaluation of Composite Ion Profile Control Agents Prepared with Oilfield Sewage

According to the demand of development in Daqing oil field, in order to reduce sewage discharge and save clean water, most of the polymer injection stations have switched to polymer solution diluted by sewage. Considering the present development trend of the oil field and requirement in terms of cost control, we should further deepen the research of formulas for all kinds of chemical sewage. Performance evaluating experiments on the long-term stability, the anti-shear property, the compatibility with initial rock debris and alkali ternary combination system of profile control agents, as well as the test for the efficiency of core displacement physical simulation of profile control and oil displacement evaluation are carried in this paper, which are intended for the composite ion profile control system that are prepared with oilfield sewage. In this paper, the long-term stable composite ion profile control agents formular prepared with oilfield sewage have been determined; the profile control effect of composite ion profile control agents prepared with sewage for cores with different permeability have been presented, and the rules of composite ion profile control agents prepared with sewage on oil displacement effect at different injection time and injection rate have been studied.Research shows that the long-term heat stability, anti-shear property, compatibility with initial rock debris and alkali ternary combination system of composite ion profile control agents prepared with sewage are well, as well as the core plugging effect and anti-corrosion performance. Oil displacement results are obviously different when profile control agents are injected at different time. Injecting profile control agents before polymer flooding works best, medium term secondly, and late stage thirdly. At the same time, the enhanced recovery rate increases with increased profile control agents injection. While the increase of enhanced oil recovery rate becomes slower when the profile control agents injection reach 0.1 PV. After profile control measures are taken, the average injection pressure and starting pressure has risen respectively by 2.7 Mpa and 2.6 Mpa; the water absorbing capacity of high permeable formation has been under control; the water absorbing capacity of low permeable formation has been strengthened; the absorbing water thickness of all wells have been increased; the breakthrough of flooded fluid in certain direction have been solved, which leads to more even polymer forward.Key words: Oil displacement effect evaluation; Performance evaluation; Composite ion profile control agents; Oil produced water preparing polymer

Study on Matching Ability Between Cement Particle Size and Permeability in the Process of Oil Reservoir Plugging

In order to satisfy the plugging demands of injecting the cement plugging agent into reservoirs with different radial depths, the technical studies of cement particle size optimization should be conducted. Through indoor experiment, the relationship between cement particle size and permeability was investigated by both macroscopic and microcosmic analysis. It is observed that the reservoirs which permeabilities are within 50~200mD are matching well with the cement agents which particle sizes are less than 5μm. And the permeabilities within 200~400mD are matching well with the cement agents which particle sizes are within 5~10μm, the permeabilities within 400~700mD are matching well with the cement agents which particle sizes are within 10~20μm, the permeabilities are above 700mD are matching well with the cement agents which particle sizes are more than 20μm. The plugging success rates of all the matching experiments are exceeding 90%. This research result is important to direct the plugging operation in the field.Key words: Plugging off and channeling prevention; Cement particle size; Permeability; Matching relationship; Experimental stud

Aggregation-induced emission fluorogens as biomarkers to assess the viability of microalgae in aquatic ecosystems

Open Access Article. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.Microalgae can be a valuable indicator for monitoring water pollution due to their sensitivity to the changes induced by pollutants in the environment. In this study, an aggregation-induced emission fluorogen was used as a novel tool to differentiate dead and live microalgae and quantify the link between live algal concentration and fluorogen intensity. Protein in the cell protoplasm is the key component contributing to fluorescence emission in algae

The Performance of Polymer Solution Added with Viscosity Stabilizer and the Evaluation of Its Oil Displacement Efficiency in Daqing Oilfield

Aiming at the low viscosity of polymer solution, which is compounded with fresh water but diluted with produced water, and at the problems concerning oil displacement efficiency, an onsite test on polymer solution with viscosity stabilizer (PSVS) is carried out. As a result, it has great and guiding significance to the application and popularization of viscosity stabilizer by studying the performance of polymer solution with viscosity stabilizer and its influence on oil displacement efficiency. In this paper, aiming at two different kinds of polymer solutions among which one is compounded with fresh water but diluted with fresh produced water and the other with aerated produced water, two laboratory evaluative tests concerning viscosity stabilization, anti-shear stability, fluidity, and absorbability of polymer solution as well as its oil displacement efficiency are done. The results of onsite application of PSVS are traced and analyzed. The viscosity stabilization of the polymer solution adding with viscosity stabilizer becomes much better than that of the normal polymer solution. The resistance and the residual resistance factors, the static oil sand adsorption rate and the dynamic core adsorption rate of the solution are all increased markedly. The working viscosity and oil displacement efficiency are improved markedly as well. In comparison with the polymer solution diluted with fresh produced water, the polymer solution diluted with aerated produced water is much better in terms of viscosity stabilization. Comparing with the normal polymer solution with viscosity stabilizer before sheared, the polymer solution which is sheared before adding with viscosity stabilizer performs obviously better in terms of viscosity stability. In contrast to the adjacent block injected with normal polymer solution, the block under onsite flooding test with injection of PSVS features that the average injection pressure increases slightly but keeps steady, the recovery speed of the average monthly water cut of production wells slows down, the thickness of the absorptive layers increases, and the periodic recovery rate improves as well.Key words: Polymer solution; Viscosity stabilizer; Daqing oilfiel

Research and Practice on Key Factors of Fracturing Technique in Changqing Zhenbei Tight Thick Layer

Zhenbei Chang 8 layer is an important evaluation layer of Changqing oilfield. In view of questions as low early fracturing effort, which affects a further exploration and development. Combined with development of volume fracturing recent years. Analyzed the ability of fracturing of reservoir from the research of rock mechanics and optimized important parameters such as displacement of pump and fracturing liquid. Way of fracture distribution was changed and complicated fracture was formed finally. Production tested improved by 2.2 times. Production of single well improved by 1.6 times. Widen the exploration area, guide the development of block, and find an important way to improve production

The prevalence of adverse reactions among individuals with three-dose COVID-19 vaccination

Background: Considering the adverse reactions to vaccination against coronavirus disease 2019 (COVID-19), some people, particularly the elderly and those with underlying medical conditions, are hesitant to be vaccinated. This study aimed to explore the prevalence of adverse reactions and provide direct evidence of vaccine safety, mainly for the elderly and people with underlying medical conditions, to receive COVID-19 vaccination. Methods: From 1st March to 30th April 2022, we conducted an online survey of people who had completed three doses of COVID-19 vaccination by convenience sampling. Adverse reaction rates and 95% confidence intervals were calculated. In addition, conditional logistic regression was used to compare the differences in adverse reactions among the elderly and those with underlying medical conditions with the general population. Results: A total of 3339 individuals were included in this study, of which 2335 (69.9%) were female, with an average age of 32.1 ± 11.4 years. The prevalence of adverse reactions after the first dose of inactivated vaccine was 24.6 % (23.1 – 26.2 %), 19.2 % (17.8 – 20.7 %) for the second dose, and 19.1 % (17.7 – 20.6 %) for the booster dose; among individuals using messenger RNA vaccines, the prevalence was 42.7 % (32.3 – 53.6 %) for the first dose, 47.2 % (36.5 – 58.1 %) for the second dose, and 46.1 % (35.4 – 57.0 %) for the booster dose. Compared with the general population, the prevalence of adverse events did not differ in individuals with underlying medical conditions and those aged 60 and above. Conclusions: For individuals with underlying medical conditions and those aged 60 and above, the prevalence of adverse reactions is similar to that of the general population, which provides a scientific basis regarding vaccination safety for these populations

Tumor Microenvironment-Activatable Nanoenzymes for Mechanical Remodeling of Extracellular Matrix and Enhanced Tumor Chemotherapy

Increased tissue stiffness is a hallmark of cancer and promotes tumor progression. It is hypothesized that decreased tumorous stress may aid or sensitize chemotherapies. To overcome extracellular matrix (ECM) stiffening and fulfill sensitized chemotherapy in one nanosystem, a reactive oxygen species-activatable nanoenzyme (SP-NE) based on a dendritic polyglycerol scaffold, integrating collagenase and paclitaxel (PTX) prodrug, is constructed. The dense and tough ECM is highly remitted by SP-NE in the tumor microenvironment (TME) mimicking gelatin hydrogel models, which causes cell shrinkage, disorders cytoskeletal constructions, and subsequently enhances chemotherapeutic efficacy. ECM softening via SP-NE downregulates mechanotransduction signaling pathways of integrin-focal adhesion kinase (FAK)-Ras homolog family member A (RhoA) implicated in cytoskeletal assembly, and integrin-FAK-phosphorylated extracellular signal regulated kinase (pERK 1/2) mediating mitosis. Notably, this programmed nanosystem in human breast MCF-7 tumor-bearing mice models displays a significant relief of ECM stress from 4300 to 1200 Pa and results in 87.1% suppression of tumor growth at a low PTX dosage of 3 mg kg(-1). The attenuated expression of the key players RhoA and pERK 1/2 involved in cellular mechano-sensing is further verified in vivo. This study thus provides a new and potential nanoplatform to selectively decrease TME stiffness for enhanced chemotherapy