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In this paper, a general framework of theoretical models and algorithm is developed to predict phase envelopes (saturation points) and quality lines of shale gas and oil in nanopores. The equation ...

Asphaltenic and other polar organic compounds in crude oil form aggregates, precipitate, adhere to surfaces, block rock pores, and severely alter the wetting characteristics of mineral surfaces within the reservoir, hindering oil recovery efficiency. Tremendous experimental efforts have been done to investigate asphaltene aggregation and precipitation from crude oil. Most of these works were carried out on planar mineral substrates or in bulk solution. However, not many direct measurements have been done in a small confined microsized pore. Examining asphaltene aggregation in a microcapillary might represent asphaltene deposition in reservoir pores better than the investigations on flat surfaces. Therefore, in this study we employ new methods to directly visualize the asphaltene aggregation process and investigate the kinetics of asphaltene aggregation in a microcapillary. The asphaltene aggregation behavior can be described by diffusion-limited-aggregation (DLA) and reaction-limited-aggregation (RLA) mod...

An experimental setup was developed to in situ measure the evolvement of the electrical resistivity during hydrate formation process to aid the interpretation of the influence of hydrate saturation...

Because of the technology limitation and safety requirement, a large amount of air-mixed coal bed methane is released directly to the atmosphere. It leads to severe waste of resources and exacerbates the greenhouse effect. This work tries to alleviate this problem by separating CH4 from a mixture of CH4 and N2 via hydrate separation method. Several experiments were systematically carried out in 6 mol % tetrahydrofuran (THF) solution to separate CH4/N2 gas mixtures containing 4.90 to 71.23 mol % CH4. The results that THF can significantly reduce the formation pressure of CH4–N2 hydrate materialize the possibility of separating CH4 and N2 using hydrate separation technology in industrial scale. CH4 can be separated effectively from CH4/N2 mixture and concentrated in hydrate phase with the presence of THF. The recovery of CH4 ranges from 34.06% to 58.16% and the separation factor is between 2.29 and 5.17. A two-stage separation process of 46.28 mol % CH4/53.72 mol % N2 with recycle is designed to increase th...

An experimental apparatus was developed to measure P-wave velocity (VP) of gas-hydrate-bearing sediment. Tetrahydrofuran (THF) was added to quicken the hydrate formation in the porous media and to synthesize hydrate-bearing sediments with uniform distribution. Methane acted as a free gas to participate in the hydrate formation. Five experimental runs were performed to examine the influence of sediment grain size and THF concentration on VP. The P-wave velocity and the amplitude for the first arrival wave signal were collected in real time during hydrate formation process. The experimental data showed that VP increases monotonically with the increase of hydrate saturation in the sediment pore space and finally tends to be a constant value. This final VP value increases with the increase of initial THF content, but the effect of sand grain size on VP is inconclusive. The variations of amplitude for the first arrival wave signal with elapsed time during hydrate formation illustrates that the amplitude increa...