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In situ combustion (ISC) has attracted extensive attention in the development of heavy oil reservoirs because of its high recovery efficiency and low energy consumption. The ISC has been successfully implemented in the PetroChina Xinjiang oilfield. However, due to the complexity in the composition of heavy oil and the ISC process itself, the molecular composition changes have not been well characterized in field samples. In this study, we used gas chromatography–mass spectrometry (GC–MS) and high-resolution Fourier transform ion cyclotron resonance mass spectrometry analysis to evaluate the molecular composition of heavy oil samples obtained from the ISC field of the Xinjiang oilfield, both before and after ISC. Small-molecule hydrocarbons were identified by GC–MS, including n-alkanes, benzenes, and naphthalenes, which have an important contribution to reducing the viscosity and improving the quality of ISC oil. Although trace amounts of fatty acids were generated in the process, the contribution of the generated fatty acids to TAN can be ignored compared with the inherent naphthenic acids. The results indicate that the ISC has a positive effect on in situ upgrading of heavy oil.

Small changes in temperature or pressure can lead to crude oil phase separation and multiple orders of magnitude change in viscosity. The one-parameter friction theory framework using the SARA-based method with the perturbed-chain statistical association fluid theory (PC-SAFT) EoS has proven to have high accuracy in viscosity predictions of light oil. However, it failed for heavy crude oil. In this work, the above model is modified in two aspects to enhance the accuracy of heavy crude oil viscosity prediction: to include the effect of asphaltene polydispersity and to include the temperature effect to the friction theory parameter. The average absolute relative deviation of the four studied heavy oils is reduced by 16.81, 24.26, 97.31, and 87.75% compared to the one-parameter f-theory SARA-based PC-SAFT model. The f-theory parameter Kcis modified as a function of temperature fitted to the viscosity at normal temperature and pressure. Following the simplicity of the expansion of the method, it is recommended to use this methodology when dealing with heavy crude oils such as those with viscosity more than 20,000 cP at 25 °C.

With the attention paid to greenhouse gas emission reduction all over the world, CO2capture, utilization and storage technology has developed rapidly. Predecessors have done a lot of work on the effect of CO2on properties of the oil, the changes of parameters after CO2injection are different. Through PVT, slim tube test and phase state simulation, this work studied the influence law of CO2injection on the properties of heavy oil in offshore reservoirs in eastern China. It defines the adaptability and oil displacement mechanism of CO2flooding in the reservoirs. In this work, 12 oil displacement experiments were carried out to quantify the effect of injection sequence, slug size, gas injection rate, and soaking time on oil recovery in the hydrogen carbon reservoir. These experimental results have indicated the influence of different factors on oil displacement effect. It provides strong evidence for the efficient development and enhanced oil recovery of the oilfield. The results indicate that the gas–water alternative injection is better than continuous water flooding or continuous CO2flooding by improving the ultimate recovery at 8.9% and 12.7% respectively. A larger CO2slug is beneficial to improve the ultimate oil recovery and the injection rate of CO2slightly affects the ultimate oil recovery factor. Longer soaking time can improve the ultimate recovery either. The ultimate recovery increases rapidly with the soaking time when it less than 24 h, but the ultimate oil recovery hardly increases when the soaking time is longer than 24 h.

To investigate the impact of total flavonoids of Epimedium(TFE) on the development of follicles of laying hens, 3 types of follicles including primary, prehierarchical, and preovulatory follicles were selected to obtain the follicular granulosa cells cultured in vitro. First, extraction of TFE was conducted by alcohol-soluble and ultrasonic methods. The effects of TFE on activity and proliferation of follicular granulosa cells were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and measuring the expression of proliferating cell nuclear antigen mRNA through real-time quantitative polymerase chain reaction, and the expression of the follicle-stimulating hormone receptor, luteinizing hormone receptor, steroidogenic acute regulatory protein, and cytochrome P450 family 11 subfamily A member 1 mRNA was detected to study the functions of TFE affecting the differentiation and hormone secretion by granulosa cells. The results showed that TFE significantly improved the proliferation of 3 types of granulosa cells and promoted the differentiation of granulosa cells and accelerated the conversion of primary follicles to prehierarchical follicles. Total flavonoids of Epimediumplayed an important role in promoting progesterone secretion by prehierarchical and preovulatory granulosa cells. The results indicated that TFE could promote proliferation and differentiation of follicular granulosa cells and improve hormone secretion and follicle development, which provided reference data for TFE used as a feed additive or safe Chinese veterinary medicine to promote the laying rate.

In this study, a strain of Trichosporonwas isolated from white pseudomembranes and ulcers formed on mucous membranes of pigeon bursas and was identified through gene sequencing. Bacteriostatic actions of Acorus gramineus, Sophora flavescens, Polygonum hydropiper, and Chinese herbal mixture on this species were explored in vitro, and the minimum inhibitory concentration of herbal medicines against Trichosporonwas determined through microdilution method. Therapeutic effects of herbal medicines on chickens infected by Trichosporonwere studied, whose results showed that minimum inhibitory concentration of A. gramineuswas 32 μg/μL, that of S. flavescenswas 2 μg/μL, that of P. hydropiperwas 120 μg/μL, and that of Chinese herbal mixture was 36 μg/μL. Antibacterial effects of S. flavescenswere the best. In accordance with animal experiments, therapeutic effects of Chinese herbal medicines on infected chickens were better than those of fluconazole. The mortality rate of the Chinese herbal medicine treatment group was 33.33%, that of the fluconazole treatment group was 46.67%, and that of the Chinese medicine protection group was 23.33%. The longer the time of Chinese medicine treatments was, the better the treatment effects would be. Glutamic oxaloacetylase values of the serum and liver in the Chinese herbal medicine treatment group were both significantly lower than those of the nontreatment group. From the results, it can be seen that A. gramineus, S. flavescens, P. hydropiper, and Chinese herbal mixture have certain inhibitory effects on Trichosporonspp. Chinese herbal medicine protections in advance could reduce Trichosporoninfections.

The initial productivity of oil wells is an important index in oilfield development. Due to the nonlinear relationship among the numerous affecting factors of productivity, productivity prediction methods based on seepage theory are difficult to characterize this nonlinear relationship. The machine learning method provides a novel theory to solve this problem. However, the data-driven machine learning method neglects the physical-based seepage theory. For balancing the advantage of the seepage model and the data-driven model, the productivity formula was used to guide the machine learning algorithm for achieving nonlinear regression in this study. Therefore, an innovative physics-guided eXtreme Gradient Boosting (XGBoost) trees algorithm was proposed to predict the initial productivity. The productivity formula was employed as the physical constraint and combined with the mean-square error (MSE) loss function of the XGBoost algorithm. A hyperparameter was introduced to balance the productivity formula and the MSE formula for constructing this adaptive physics-guided loss function. Moreover, the random subsampling cross-validation approach was adopted to train the XGBoost model. The grid search approach was introduced to optimize the hyperparameters of the model. The results show that based on the numerical simulator data, the initial productivity prediction accuracy of physics-guided XGBoost was verified as 94.67%, which was higher than the completely data-driven model. Moreover, the robustness of the novel adaptive physics-guided loss function for improving forecasting accuracy had been validated with sample sizes between 50 and 20000. By introducing the physics-guided sampling process and loss function, the applicability of the XGBoost algorithm has been extended to small sample conditions. Furthermore, the practical accuracy of physics-guided XGBoost was verified as 84.74% by 162 oil wells in the Penglai oilfield. Therefore, the application value of combining the physical knowledge with the XGBoost model has been confirmed in oilfield situations.

Recently, a new technology, the so-called multithermal fluids huff and puff, to exploit extra heavy oil reservoirs has been applied successfully in several shallow heavy oil reservoirs in China. However, the use of this technology in deep extra heavy oil reservoirs is rare. Successful application of this technique in deep extra heavy oil reservoirs requires a good knowledge of the phase behavior and physical properties of multithermal fluids and extra heavy oil mixture. The major components of multithermal fluids mixtures are steam, N2, and CO2. In this work, targeting the application of multithermal fluids injection in heavy oil reservoirs, we conduct PVT experiments on the N2/CO2/heavy oil mixtures under deep reservoir conditions and develop equation of state models for representing these PVT data. Experimentally, it is found that CO2solubility in extra heavy oil decreases with an increasing temperature at given pressure. Contrary to CO2, N2solubility in extra heavy oil increases with an increasing temperature at a given pressure. Theoretically, the extra heavy oil is split and lumped into eight pseudocomponents to characterize the critical temperatures, critical pressures, acentric factors, and other properties by using the Kesler–Lee formulas. To match the solubility obtained in the experiments, two binary interaction parameter (BIP) correlations in the Peng and Robinson equation of state (PR EOS) are selected to calculate the solubility of both N2and CO2in extra heavy oil (Peng and Robinson, 1976). At a given temperature, the exponent in each BIP correlation is optimized to match the measured solubility of N2or CO2in extra heavy oil. We validate the optimized BIP exponents in the PR EOS model by using them to reproduce the measured saturation pressures and swelling factors of the ternary N2/CO2/heavy oil mixtures. The validation results show that the BIP correlations with the optimized exponents can reproduce the measured swelling factors and saturation pressures of N2/CO2/heavy oil mixtures with good accuracy. In addition, by carrying out example calculations using the tuned PR-EOS model, we discuss the possible multiphase equilibria that can be encountered under reservoir conditions when the multithermal fluids (N2/CO2/H2O) are injected into an extra heavy oil reservoir.

Hydraulic fracturing is the significant technology for exploiting tight resources. Spontaneous water imbibition is an important mechanism governing the process of hydraulic fracturing, and the water imbibition from the fracture into the matrix is an essential factor that affects the reservoir production performance. In this study, imbibition experiments and nuclear magnetic resonance (NMR) testing were combined to analyze fluid flow tight core samples in a pore-scale level. The imbibition experiments were categorized into two systems, the gas/water/rock system and the oil/water/rock system. The NMR measurements were performed at different times for these two systems. The relationship between T2relaxation time, pore radius, and pore types was established. Theoretical models describing water imbibition into porous media were used to facilitate the interpretation of the experimental results. The results demonstrate that the volume of imbibed water is large during the early imbibition period and that the imbibition recovery increases rapidly as time proceeds. The volume of imbibed water reaches a constant level at the end of the experiment. The volume of imbibed water in the oil/water/rock experiment is less than that in the gas/water/rock experiment; however, the experiment shows an inverse relation for the duration of the imbibition. For the gas/water/rock system, the water is originally imbibed into micropores and small mesopores present in the natural core samples. There are four types of T2distributions related to the oil/water/rock imbibition process. Finally, the experimental results indicate the effect of boundary conditions, wettability, temperature, and oil viscosity on water imbibition. The oil recovery due to water imbibition for the oil/water/rock is mainly controlled by the capillary force, gravity force, and characteristic length of the core sample. Water-wet conditions are more preferable for spontaneous imbibition. Through a detailed study of imbibition experiment and NMR testing, significant insight is provided into the fluid flow in the tight porous media.

Aspergillus flavusand Aspergillus fumigatuswere derived and identified from the ducks infected with fungi. In order to investigate the effectiveness of Chinese herbal medicines against Aspergillus flavusand Aspergillus fumigatus, in vitro antibacterial test and animal infection control test were conducted to study the antibacterial activity of the Chinese medicine mixture which was compatible with Acorus gramineus, Phellodendron chinensis, and Cassia obtusifolia. According to the results, the liver of chickens infected with Aspergillus flavusand Aspergillus fumigatusdisplayed granulomatous lesions, indicating that the isolation of pathogen from the lungs of sick ducks is also pathogenic to chickens. As suggested by the results of in vitro drug sensitivity test, the mixture 1 MIC80was the minimum, the MIC80of Aspergillus flavuswas 16 μg/μL, and the MIC80of Aspergillus fumigatuswas 4 μg/μL. In a petri dish of the same concentration, the colony diameter of Aspergillus flavusand Aspergillus fumigatusin Mixture 1 was the minimum. Besides, Aspergillus flavuscolonies grew when the concentration was 64 μg/μL, and Aspergillus fumigatuscolonies grew when the concentration was 4 μg/μL, which suggests the more significant inhibitory effect of Mixture 1 on Aspergillus flavusand Aspergillus fumigatus. According to the results of animal experiments, there was a significantly lower activity level of Glutamic oxaloacetic transaminase (GOT) and Glutamate pyruvic transaminase (GPT) in the protection group and the treatment group than in the bacterial infection group. As indicated by the blood smear results, there were more neutrophils in the infected group than in the prevention group and the treatment group. Thus, it can be seen from that the Mixture 1 produced preventive and therapeutic effects on the chickens infected with Aspergillus flavusand Aspergillus fumigatus.

Previously, a fungus was isolated from a diseased pigeon group clinically suspected of being infected with Candida. The fungus was subsequently identified as Candida glabratausing morphology, physiology, biochemistry, and molecular biology testing methods. In the present study, in order to determine the controlling effects of Chinese herbal medicine for Candida glabrata, the bacteriostatic effects of the ethanol extracts Acorus gramineus, Sophora flavescens, Polygonum hydropiper, Cassia obtusifolia, Pulsatilla chinensis, Dandelion, and Cortex phellodendri on Candida glabrata in-vitro were analyzed. The results showed that the minimum inhibitory concentrations (MIC80) of Cortex phellodendri was 0.25 μg/μL. Meanwhile, that of Sophora flavescens was 32 μg/μL; Cassia obtusifolia was 56 μg/μL; Acorus gramineus and Polygonum hydropiper was 64 μg/μL; and Pulsatilla chinensis was 112 μg/μL. However, MIC80for Dandelion was undetectable. In addition, improved drug sensitivity tests revealed that colonies had grown after 24 hours in the blank group, as well as the Polygonum hydropiper, Pulsatilla chinensis, Dandelion, and ethanol groups. The colonies first appeared at the 48-hour point in the other drug sensitive medium of Chinese herbal medicine. However, no colony growth was found in Cortex phellodendri medium, and the formation of the maximum colony diameter in that group was later than the blank group (for example, 96 hours in the blank group and 120 hours in the Chinese herbal medicine group). It was observed that only 17 colony forming units (CFU) had grown in 125 μg/μL of the Sophora flavescens medium, which was significantly different from other groups. Also, the final colony diameter was significantly smaller than those of the other experimental groups. Therefore, it was determined that the Acorus gramineus, Sophora flavescens, Polygonum hydropiper, Cassia obtusifolia, Pulsatilla chinensis, and Cortex phellodendri had certain inhibitory effects on the growth of the Candida glabrata. Among those, it was observed that the Cortex phellodendri had the strongest inhibitory effects, followed by the Sophora flavescens. In the future, these Chinese herbal medicines are expected to be used to treat the fungal infections related to Candida glabrata in poultry in order to improve production performance.

The objective of this experimental study was to examine the effects of the Chinese herbal medicines Patchouliand Elsholtziaon the follicular granulosa cells of hens undergoing heat stress conditions. In the current investigation, hen follicular granulosa cells were isolated from the pre-hierarchical follicles of layer hens and then cultured in-vitro. The cells were randomly divided into the six groups. Following the completion of this study's experiments using different heat stress and medicinal treatments, the cell activities of each group were measured using an MTT method. The levels of the heat shock protein 70 (HSP70) were detected using ELISA. The expressions of the steroidogenic acute regulatory protein (StAR) mRNA; cytochrome P450 family 11, subfamily A, member 1 (CYP11A1) mRNA; proliferating cell nuclear antigen (PCNA) mRNA; and the follicle stimulating hormone receptor (FSHR) were detected using the real-time quantitative polymerase chain reactions. The concentration levels of estrogen and progesterone in the cell supernatant of each group were measured using ELISA. The results showed that cell activity had significantly decreased following the heat stress treatments at 43℃, 44℃, and 45℃ (P ˂ 0.01), respectively. Meanwhile, cell activities observed in Patchouliand Elsholtziawere found to be much better than those of heat stress group (P ˂ 0.05). In addition, the expression levels of HSP70 in the follicular granulosa cells of Patchouliand Elsholtziagroups were lower than those of heat stress group. Patchouliand Elsholtziacan maintained expressions of the receptor at 43℃. This study determined that the estrogen and progesterone in the supernatant fluid of Patchouliand Elsholtziawere higher than those observed in heat stress. Therefore, the results obtained in this study indicated that the Patchouliand Elsholtziatreatments administered prior the heat stress experiments had successfully protected the follicular granulosa cells from heat damages while maintaining the normal secretory functions of the granulosa cells.