Establishment and application of logging saturation interpretation equation in vuggy reservoirs

Vuggy reservoirs are the most common, albeit important heterogeneous carbonate reservoirs in China. However, saturation calculations using logging data are not well developed, whereas Archie method is more common. In this study, electrical conduction in a vuggy reservoir is theoretically analyzed to establish a new saturation equation for vuggy reservoirs. We found that vugs have a greater effect on saturation than resistivity, which causes inflection in the rock-electricity curve. Using single-variable exPeriments, we evaluated the effects of rug size, vug number, and vug distribution on the rock-electricity relation. Based on the general saturation model, a saturation equation for vuggy reservoirs is derived, and the physical significance of the equation parameters is discussed based on the seepage-electricity similarity. The equation parameters depend on the pore structure, and vugs and matrix pore size distribution. Furthermore, a method for calculating the equation parameters is proposed, which uses nuclear magnetic resonance （NMR） data to calculate the capillary pressure curve. Field application of the proposed equation and parameter derivation method shows good match between calculated and experimental results, with an average absolute error of 5.8%.

Study of Stability of Saturated Salt Solutions Cells

This paper study stability of saturated salt solutions cells at 25 ℃. These cells were prepared and measured at National Institute for Standard （NIS-Egypt） to study the stability of the saturated salt solutions. The study was carried out using three saturated salt solutions, which are Potassium Acetate 22.5%, Potassium Iodide 68.9% and Potassium Sulphate 97.3% to cover low, medium and high relative humidity. The study was carried out using different shapes and volumes half liter spherical, liter spherical and liter conical per each salt which was prepared. The apparatus which used in measurement system in the first time are the same which used after ten years. The results show that the change of relative humidity value after ten years ranged from 0.1% to 0.7%. This value is suitable within uncertainty ＋ 2%. The period of stability for each run for all cells was found to be more than five hours and this period enough for calibration. The measurements show that the cells are stable for more than ten years with accepted value.

Advances in Supercritical Fluid Crystallization

The supercritical fluid crystallization technique is a novel technology for preparing ultrafine particles. This paper introduced the concept and features of the technique with an emphasis on three kinds of supercritical fluid crystallization techniques, i.e. rapid expansion of supercritical solutions, supercritical fluid anti-solvent and particles from gas saturated solutions Some questions and the prospect of this technique were also discussed.

Experimental Study on Preparation of Natural Gas Hydrate by Crystallization

In this paper, the saturated solution crystallization method is proposed to promote the formation of hydrate by means of the known similarities between the hydrate formation process and the crystallization process. In this method,adding the second phase crystals was used to replace the spontaneous formation of hydrate crystal nuclei to form hydrate.The effects of saturated Na_2SO_4, MgSO_4, NH_4HCO_3 and CuSO_4 solutions on the formation rates of natural gas hydrate and gas storage capacity were investigated. The results showed that the saturated solution had an influence on the hydrate formation process. Under the given experimental conditions, the saturated Na_2SO_4 solution showed a highest increase in the hydrate formation rate, and the average hydrate formation rate in its presence was 11.8 times higher than that obtained in the deionized water. Moreover, the largest formation rate of gas hydrates observed in the saturated Na_2SO_4 solution was 386 times bigger than that in the deionized water, and the gas storage capacity increased by 10 times. In addition, the average hydrate formation rate in the saturated Mg SO_4 solution was faster than that in water by 20 times. The largest formation rate of gas hydrates in the saturated MgSO_4 solution was 165 times faster than that obtained in the deionized water, and the gas storage capacity increased by 6.2 times. The saturated NH_4HCO_3 and saturated CuSO_4 solutions also influenced the formation process of hydrate. Therefore, the crystallization method of saturated solution can be used to achieve a highefficiency preparation of natural gas hydrates, which provides theoretical guidance for the storage of natural gas in the form of hydrate.

Pulsation Treatment on the Modification of Crystal with Cold Simulation

Since the separation of crystal of KCl saturated aqueous is similar to the crystallization of liquid metals, the melts nucleation can be simulated by the experiment of the crystal of salt aqueous solution. In this experiment pulsation treatment was imposed on KCl saturated aqueous in order to study the effect of pulsation treatment on crystallization in the salt solution, and the influence of different pulsation treating time, super-heating and bine of prescription were investigated. The results show that it is possible to modify the crystallization over satured solution temperature and the degree of under-cooling for salt crystal separation was reduced by applying pulse treating on KCl saturated aqueous solution. In addition, this technology may generate embryos for nucleation even at the temperature over melting point or satured solubility.

Response of saturated porous media subjected to local thermal loading on the surface of semi-infinite space

Heat source function method is adopted in the present paper to derive elementary solutions of coupled thermo-hydro-mechanical consolidation for saturated porous media under conjunct actions of instantaneous point heat source, instantaneous point fluid source and constant volume force. By using the so-called fictitious heat source method and images method, the solutions of a semi-infinite saturated porous medium subjected to a local heat source with time-varied intensity on its free surface are developed from elementary solutions. The numerical integral methods for calculating the unsteady temperature, pore pressure and displacement fields are given. The thermomechanical response are analyzed for the case of a circular planar heat source. Besides, the thermal consolidation characteristics of a saturated porous medium subjected to a harmonic thermal loading are also given, and the fluctuation processes of the field variables located below the center of heat source are analyzed.

β-Cyclodextrin inclusion complex： preparation, characterization, and its aspirin release in vitro

In this work, the optimal clathration condition was investigated for the preparation of aspirin-β-cyclodextrin （Asp-β-CD） inclusion complex using design of experiment （DOE） methodology. A 3-level, 3-factor Box-Behnken design with a total of 17 experimental runs was used. The Asp-β-CD inclusion complex was prepared by saturated solution method. The influence on the embedding rate was investigated, including molar ratio of β-CD to Asp, clathration temperature and clathration time, and the optimum values of such three test variables were found to be 0.82, 49C and 2.0 h, respectively. The embedding rate could be up to 61.19%. The formation of the bonding between -COOH group of Asp and O-H group of β-CD might play an important role in the process of clathration according to FT-IR spectra. Release kinetics of Asp from inclusion complex was studied for the evaluation of drug release mechanism and diffusion coefficients. The results showed that the drug release from matrix occurred through Fickian diffusion mechanism. The cumulative release of Asp reached only 40% over 24 h, so the inclusion complex could potentially be applied as a long-acting delivery system.