Applying chemical enhanced oil recovery (EOR) to shale and tight formations is expected to accelerate China’s Shale Revolution as it did in conventional reservoirs. However, its screening and modeling are more complex. EOR operations are faced with choices of chemicals including traditional surfactant solutions, surfactant solutions in the form of micro-emulsions (nano-emulsions), and nano-fluids, which have similar effects to surfactant solutions. This study presents a systematic comparative analysis composed of laboratory screening and numerical modeling. It was conducted on three scales: tests of chemical morphology and properties, analysis of micro-oil-displacing performance, and simulation of macro-oil-increasing effect. The results showed that although all surfactant solutions had the effects of reducing interfacial tension, altering wettability, and enhancing imbibition, the nano-emulsion with the lowest hydrodynamic radius is the optimal selection. This is attributed to the fact that the properties of the nano-emulsion match well with the characteristics of these shale and tight reservoirs. The nano-emulsion is capable of integrating into the tight matrix, interacting with the oil and rock, and supplying the energy for oil to flow out. This study provides a comprehensive understanding of the role that surfactant solutions could play in the EOR of unconventional reservoirs.

Distributed Video Coding (DVC) is a new video coding scheme that mainly uses the availability of decoder side information to reduce the complexity of the encoder. The quality of the side information has an important influence on the performance of the distributed video coding system. At present, the generation of side information is mainly based on a model that uses inter-frame correlation for motion estimation. In order to make full use of the intra-frame self-similarity of the side information frame, we use the idea of image denoising, and propose an improved side information generation method. Since the initial side information frame can be viewed as a noisy version of the Wyner-Ziv (WZ) frame, improving the side information frame can be translated to denoising the frame. The experimental results show that the quality of the side information obtained by the proposed scheme has been significantly improved, thereby effectively improve the performance of distributed video coding.