Nonlinear Flow Characteristics and Horizontal Well Pressure Transient Analysis for Low-Permeability Offshore Reservoirs

Threshold pressure gradient (TPG) and stress sensitivity which cause the nonlinear flow in low permeability reservoirs were carried out by experiments. Firstly, the investigation of existing conditions of TPG for oil flow in irreducible water saturation low-permeability reservoirs was conducted and discussed, using the cores from a real offshore oilfield in China. The existence of TPG was proven. The relationship between TPG and absolute permeability was obtained by laboratory tests. TPG increases with decreasing absolute permeability. Then, stress sensitivity experiment was carried out through depressurizing experiment and step-up pressure experiment. Permeability modulus which characterizes stress sensitivity increases with decreasing absolute permeability. Consequently, a horizontal well pressure transient analysis mathematical model considering threshold pressure gradient and stress sensitivity was established on the basis of mass and momentum conservation equations. The finite element method (FEM) was presented to solve the model. Influencing factors, such as TPG, permeability modulus, skin factor, wellbore storage, horizontal length, horizontal position, and boundary effect on pressure and pressure derivative curves, were also discussed. Results analysis demonstrates that the pressure transient curves are different from Darcy’s model when considering the nonlinear flow characteristics. Both TPG and permeability modulus lead to more energy consumption and the reservoir pressure decreases more than Darcy’s model

Preparation of novolacs using phenolic rich components as partial substitute of phenol from biomass pyrolysis oils

The possibility of using phenolic rich components (water insoluble fraction) from biomass pyrolysis oil as partial substitute of phenol in synthesis of high-ortho phenolic novolac under the catalyst of HCl/Zn(AC)2 has been proved using differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (FT-IR). Synthesis of novolac resins with different concentration (10, 20, 30 and 40 wt %) of phenolic rich components were investigated. Curing reaction of synthesized resins and DSC analysis showed that cure time of novolac was increased with the increasing amount of phenolic rich components and FT-IR analysis showed that the resins were high-ortho structure. It was determined that in order to obtain fast curing property, the concentration of phenolic rich components used in reaction should be below 10% (according to total amount of phenol). KEY WORDS: Biomass, Pyrolysis, Phenol, Formaldehyde, Novolac, Preparation  Bull. Chem. Soc. Ethiop. 2010, 24(2), 251-257

Long Cracks Fractured Vertical Well Numerical Simulation and Application for Tight Oil Reservoir

AbstractTight oil has currently become a hot issue in worldwide non-conventional oil exploration. Based on the core displacement experiments, the existence of low velocity non-Darcy flow was proven. So the three-dimensional three-phase Long cracks fractured vertical well model was established with considering the non-Darcy flow. A new numerical simulation software for long cracks fractured vertical well was developed. Results are compared to the simulation results of Darcy flow with the commercial simulator Eclipse. Using this new software, the comprehensive comparison and analysis of the simulation results of Darcy flow and non-Darcy flow were provided including oil production rate, water cut, reservoir pressure. The numerical simulator based on low velocity non-Darcy flow can describe tight sandstone reservoir development dynamic characteristics more exactly

Microwave Assisted Hydrolysis Of Holocellulose Catalyzed With Sulfonated Char Derived From Lignin-Rich Residue

A microwave assisted green process has been developed for production of sugars through liquefying holocellulose catalyzed with sulfonated char derived from the lignin-rich residue produced during pretreatment of lignocellulose. Various reaction parameters including the hydrolysis temperature, hydrolysis time, catalyst content, and the ratio of water to feedstock were evaluated. The maximum sugars yield of 82.6% (based on the dry mass of holocellulose) was obtained under the optimum reaction conditions. The sulfonated char showed superior catalytic performance to that of dilute sulfuric acid in converting holocellulose into sugars under microwave irradiation

Synthesis of tributyl citrate using SO42-/Zr-MCM-41 as catalyst

Zirconium-containing mesoporous molecular sieve SO42-/Zr-MCM-41 was synthesized for catalyst in synthesis of tributyl citrate. The structure was characterized by XRD, N2 Ad/De isotherms and FT-IR. The results indicated that the solid acids show good catalytic performance and are reusable. Under optimum conditions and using SO42-/Zr-MCM-41 as catalyst, the conversion of citric acid was 95%. After easy separation of the products from the solid acid catalyst, it could be reused three times and gave a conversion of citric acid not less than 92%. The structure of tributyl citrate was characterized by FT-IR and 1H-NMR.KEY WORDS: Mesoporous molecular sieve, Tributyl citrate, Synthesis Bull. Chem. Soc. Ethiop. 2011, 25(1), 147-150

Preparation of 2-Methylnaphthalene from 1-Methylnaphthalene via Catalytic Isomerization and Crystallization

Large amounts of residual 1-methylnaphthalene are generated when 2-methylnaphthalene is extracted from alkyl naphthalene. In order to transform waste into assets, this study proposes a feasible process for preparing 2-methylnaphthalene from 1-methylnaphthalene through isomerization and crystallization. The 1-methylnaphthalene isomerization was carried out in a fixed-bed reactor over mixed acids-treated HBEA zeolite. The results showed that acidic properties of catalysts and reaction temperature were associated with the 2-methylnaphthalene selectivity, yield and catalytic stability. At a high reaction temperature of 623 K, the 2-methylnaphthalene yield was 65.84 %, and the deactivation rate was much lower. The separation of reaction products was then investigated by two consecutive crystallization processes. Under optimal conditions, the 2-methylnaphthalene purity attained 96.67 % in the product, while the yield was 87.48 % in the refining process. Copyright © 2018 BCREC Group. All rights reserved Received: 10th May 2018; Revised: 16th July 2018; Accepted: 17th July 2018 How to Cite: Sun, H., Sun, K., Jiang, J., Gu, Z. (2018). Preparation of 2-Methylnaphthalene from 1-Methylnaphthalene via Catalytic Isomerization and Crystallization. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (3): 512-519 (doi:10.9767/bcrec.13.3.2650.512-519) Permalink/DOI: https://doi.org/10.9767/bcrec.13.3.2650.512-51

Induction of cytoprotective autophagy in PC-12 cells by cadmium

AbstractLaboratory data have demonstrated that cadmium (Cd) may induce neuronal apoptosis. However, little is known about the role of autophagy in neurons. In this study, cell viability decreased in a dose- and time-dependent manner after treatment with Cd in PC-12 cells. As cells were exposed to Cd, the levels of LC3-II proteins became elevated, specific punctate distribution of endogenous LC3-II increased, and numerous autophagosomes appeared, which suggest that Cd induced a high level of autophagy. In the late stages of autophagy, an increase in the apoptosis ratio was observed. Likewise, pre-treatment with chloroquine (an autophagic inhibitor) and rapamycin (an autophagic inducer) resulted in an increased and decreased percentage of apoptosis in contrast to other Cd-treated groups, respectively. The results indicate that autophagy delayed apoptosis in Cd-treated PC-12 cells. Furthermore, co-treatment of cells with chloroquine reduced autophagy and cell activity. However, rapamycin had an opposite effect on autophagy and cell activity. Moreover, class III PI3 K/beclin-1/Bcl-2 signaling pathways served a function in Cd-induced autophagy. The findings suggest that Cd can induce cytoprotective autophagy by activating class III PI3 K/beclin-1/Bcl-2 signaling pathways. In sum, this study strongly suggests that autophagy may serve a positive function in the reduction of Cd-induced cytotoxicity