The influence of fluorochemical-modified graphene oxide on the gas-wetting alteration of reservoir cores

Enhanced Sorption for the Oil Spills by SDS-Modified Rice Straw

Frequent oil spills have caused serious consequences to the ecosystem and environment. Therefore, in order to reduce and eliminate the impact of oil spills on biology and the environment, oil spill remediation materials must be considered. As a kind of cheap and biodegradable natural organic cellulose oil-absorbing material, straw has an important practical significance in the treatment of oil spills. In order to improve the ability of rice straw to absorb crude oil, rice straw was first treated with acid and was then modified with sodium dodecyl sulfate (SDS) through a simple charge effect. Finally, the performance of oil absorption was tested and evaluated. The results illustrate that the oil absorption performance was greatly improved under the conditions of 10% H2SO4, for a 90 min reaction at 90 °C, under 2% SDS, and reacted for 120 min at 20 °C, and the rate of adsorption for rice straw to crude oil was raised by 3.33 g/g (0.83 to 4.16). Then, the rice stalks before and after the modification were characterized. Contact angle analysis shows that the modified rice stalks display better hydrophobic–lipophilic properties than unmodified rice stalks. The rice straw was characterized by XRD and TGA, and the surface structure of the rice straw was characterized by FTIR and SEM, which explain the mechanism of surface-modified rice straws with SDS to improve their oil absorption capacity.

An overview on the enhanced gas condensate recovery with novel and green methods

A consideration of the negative environmental aspects of fossil fuels has made natural gas the best choice to meet the human demand for energy. The condensate gas reservoir is one source of gases that tolerates skin problems (liquid blockage). Conventional methods for inhibiting or removing liquid blockages are momentary treatments, non-eco-friendly, and expensive. Therefore, new methods have been introduced, such as wettability alteration toward liquid repellency, renewable energies, thermochemical reactions and waves for heating reservoirs, and CO₂ injection. This paper reviews the methods for altering the wettability of porous media by fluorochemicals, fluorinated nanoparticles (NPs), and free fluorocarbon materials from natural substances. NPs, particularly silicon-based types, as a green, clean, and emerging technology that are more compatible with the environment, were investigated for their ability to alter the wettability and upgrade conventional materials, such as polymers and surfactants. The feasibility of using renewable energies, thermochemical reactions, and waves for heating the gas condensate reservoir to overcome the skin problem and return the reservoir to the reasonable and economical gas production is reviewed. Finally, CO₂ injection is introduced as a multi-purpose green method to enhance gas condensate recovery and allow CO₂ sequestration.

Fluoropolymer Microemulsion: Preparation and Application in Reservoir Wettability Reversal and Enhancing Oil Recovery

Reservoir wettability is an important factor in the process of reservoir reconstruction. Especially in hydrophilic formation, it is easy to cause a water-locked phenomenon. A new type of fluoropolymer microemulsion was prepared by emulsion polymerization, and its structure and properties were characterized. The average particle size in the prepared emulsion was about 2.0 μm. The emulsion had good stability and wettability reversal performance for the storage of 30 days. After the treatment of 2.0 wt % emulsion, the contact angle between the core and water changed from 26 to 128°, the core surface free energy decreased from 66 to 2.6 mN/m, and the saturated water imbibition amount of the core decreased from 1.38 to 0.15 g. The ability of the fluoropolymer microemulsion to enhance oil recovery was evaluated by the visual displacement experiment. The fluoropolymer microemulsion can increase the displacement efficiency by more than 10%. The wettability of the core changed from hydrophilicity to hydrophobicity, and wettability reversal was achieved.