Time and Dose-related Effects of the Pyrethroid Fluvalinate on Haemolymph Carbohydrates and Gut Lipids of Honeybees,Following in vivo Injection of very Low Doses

The injection to emerging adult workerbees with fluvalinate doses ranging from 1 femtomol to 1 nanomol per individual resulted in a reduction of haemolymph carbohydrate concentrations, particularly at the lowest dose 1 hour after injections. At the same time, a large increase was observed for triacylglycerols and to a much lesser extent for steroids and phospholipids with 0.1 picomol per bee. By contrast, fatty acids, steroids and triacylglycerols exhibited a depress at the higher dose. Most responses were thus biphasic, showing that much attention should be paid to the effects of very low doses of pesticide.

Mixture Preparation and Combustion of CNG Low-Pressure Compound Direct Injection Spark-Ignited Engines

A set of compressed natural gas (CNG) multi-point direct injection system of spark-ignited engines and the corresponding measurement and data acquisition systems were developed in this paper. Based on different injection modes, the mixture formation and combustion of CNG low-pressure direct injection (LPDI) engines were studied under varying factors such as air/ fuel ratio, injection timing. Meanwhile, three-dimensional simulations were adopted to explain the mixture formation mechanisms of CNG low-pressure compound direct injection (LPCDI) mode. On the basis of test results and simulation of the mixture homogeneous degree, the conception of injection window was proposed, and the LPCDI mode was proved to be more beneficial to the mixture concentration stratification formation in cylinder under lean-burning conditions, which resulted in effective combustion and stability.

Layered injection technology for chemical flooding of Class-Ⅲ oil reservoirs in the Daqing Oil Fields complex,Songliao Basin,Northeast China

The Class-Ⅲ oil reservoirs of Lasaxing oilfield in the Daqing Oil Fields complex have geological oil reserves of 1.86 billion tonnes,an oil recovery of 39%,with remaining reserves accounting for more than 45%of the total geological reserves of the oilfield.Therefore,they have considerable potential for future oil production.The current layered injection technologies fail to achieve effective control over the low single-layer injection rates since they can only produce low throttle differential pressure under low injection rates(5-20 m^(3)/d).In this study,a symmetrically-structured double-offset-hole injection allocator and a novel throttling component were developed.Their spatial layout was constructed and mechanical parameters were optimized using finite element analysis,which allows for expanding the flow rate range at low injection rates.According to experimental results,the throttle differential pressure increased from 0.2 MPa to 0.8 MPa at an injection rate of 5 m^(3)/d,and the range of the single-layer flow rates expanded from 20-70 m^(3)/d to 5-70 m3/d.The field test results show that the effective production of oil layers with medium and low permeability was achieved and that the ratio of producing oil layer thickness to the total reservoir thickness increased by 9.7%on average.Therefore,this study provides valuable technical support for the effective chemical-flooding-based development of Class-Ⅲ oil reservoirs.

Simulation of low and high salinity water injection method to determine the optimum salinity

Investigating the enhanced oil recovery leads to optimal production,protection and reduction of lateral impacts.Low salinity water injection(LSWI)is one of the significantly improved oil recovery(IOR)techniques for changing the amount of wettability in the carbonate fractured reservoirs.The utilization of this methodology in terms of high efficiency in displacing light crude oils to the medium-gravity crude oils,water sources availability and its sustainability for pushing the oil which leads to appropriate economic occasions,are being compared with other IOR/EOR techniques.In this study,the best injection modelling pattern is based on the highest rate of recovery factor.Comparison of“high and low salinity water injection method”with“pure water injection method”is performed in an oil reservoir.Overall,analyzing the sensitivity on the high and low salinity according to the moderately low recovery factor of high and low salinity among the injection scenarios illustrates the low sensitivity of this parameter on a fractured carbonate reservoir.By reviewing different scenarios,it could be demonstrated that if the water injection could be applied to the reservoir from the preliminary times of production,the recovery factor rate would be increased.Thereby,higher appropriate efficiency and better supplement have resulted.Pure water injection has a high recovery factor than salty water injection.By the way,these two methods have little differences in calculating recovery methods.Besides,this parameter is significantly depended on wellhead equipment properties,safety factor and economic issues(water production).

Effect of heterogeneity on engineered water injection in carbonates using five-spot sector model:A numerical study

One of the promising and emerging enhanced oil recovery techniques in both sandstones and carbonates is engineered water injection(EWI).However,few studies discussed the field-scale applications of this technique in heterogeneous carbonate formations.This paper is an extension of our previous work of the EWI technology at core-scale.This research numerically investigates heterogeneity effect on EWI technique in carbonates at field-scale using five-spot models.Three synthetic five-spot sector models were considered including homogeneous,heterogeneous with permeability channeling,and heterogeneous with gravity underride.The results showed that EWI improves both volumetric and displacement sweep efficiencies compared to conventional formation water injection(FWI)for all models investigated.Also,tracer method is recommended for better estimation of volumetric sweep efficiency as opposed to fractional flow method.Moreover,secondary EWI outperforms other techniques including secondary FW and tertiary EWI.In addition,the observed delay in tertiary EWI can be reduced by increasing well injection pressure and sulfate concentration in the engineered water.An optimum sulfate concentration of 25,000 ppm is recommended for achieving the highest oil recovery by EWI.This study gives more insight into understanding the performance of the EWI technique at field-scale.Recommendations for boosting the performance of this technique have been discussed,which assure more certainty and lower risk.