In a method for measuring the vapor pressure of liquid and solid substances, in which a sample of the substance is arranged in a variable volume of a measuring cell, the measuring cell is gas-tightly closed. The volume of the measuring cell is increased until reaching a measuring volume, and at least one first value of the gas pressure prevailing after the increase in volume is measured. The volume of the measuring cell is additionally reduced until reaching the measuring volume, and at least one second value of the gas pressure prevailing after the reduction of the volume is measured. The vapor pressure is calculated from the at least one first and at least one second measured values.

The present invention belongs to the field of gas solubility measurement, and provides a measuring device and method for gas solubility in a natural gas hydrate solution system. The measuring device mainly comprises a reaction system, a sampling system and a data analysis system. The present invention can be used for measuring gas solubility in a natural gas hydrate solution system at different temperature, pressure and salt ion conditions, and exploring influence of different environmental conditions on the gas solubility when hydrate-liquid water biphase equilibrium is achieved. The present invention in characterized in that the structure is simple, the operation is easy, sampling is carried out at a constant pressure to avoid damage to phase equilibrium and dissolution equilibrium of the systems, and a microfilter is used to ensure that a liquid sample taken does not contain hydrate crystals, so that experimental data has a relatively high accuracy.

The present invention belongs to the field of gas solubility measurement, and provides a measuring device and method for gas solubility in a natural gas hydrate solution system. The measuring device mainly comprises a reaction system, a sampling system and a data analysis system. The present invention can be used for measuring gas solubility in a natural gas hydrate solution system at different temperature, pressure and salt ion conditions, and exploring influence of different environmental conditions on the gas solubility when hydrate-liquid water biphase equilibrium is achieved. The present invention in characterized in that the structure is simple, the operation is easy, sampling is carried out at a constant pressure to avoid damage to phase equilibrium and dissolution equilibrium of the systems, and a microfilter is used to ensure that a liquid sample taken does not contain hydrate crystals, so that experimental data has a relatively high accuracy.

Systems and methods for measuring air withing a fluid and for mitigating damage to a metalworking tool are disclosed. A system for measuring air within a fluid includes a fluid path having a first end and a second end; a first valve having an open position and a closed position, wherein fluid can pass through the first valve in the open position and fluid is prevented from passing through the first valve in the closed position; a first sensor located between the first valve and the second end; and a second sensor located between the first sensor and the second end, wherein the second end is higher than the first end.

Systems and methods for measuring air withing a fluid and for mitigating damage to a metalworking tool are disclosed. A system for measuring air within a fluid includes a fluid path having a first end and a second end; a first valve having an open position and a closed position, wherein fluid can pass through the first valve in the open position and fluid is prevented from passing through the first valve in the closed position; a first sensor located between the first valve and the second end; and a second sensor located between the first sensor and the second end, wherein the second end is higher than the first end.

A method of recovering crude oil from a reservoir by: determining a depletion pressure for providing a lights-depleted crude oil comprising a reduced amount of light ends including methane, nitrogen, carbon dioxide (CO.sub.2), or a combination thereof and having a CO.sub.2 multi contact Minimum Miscibility Pressure (CO.sub.2-MMP) below a CO.sub.2-MMP of a native crude oil, wherein the native crude oil is crude oil extracted from the reservoir prior to primary oil recovery therefrom; depleting the pressure of the reservoir from an initial reservoir pressure to the determined depletion pressure, thus providing the lights-depleted crude oil; repressurizing the reservoir to an operating pressure for recovering the lights-depleted crude oil from the reservoir via carbon dioxide (CO.sub.2) injection; injecting CO.sub.2 into the reservoir via at least one injection well; and recovering at least a portion of the lights-depleted crude oil from the reservoir via at least one production well.

A method of recovering crude oil from a reservoir by: determining a depletion pressure for providing a lights-depleted crude oil comprising a reduced amount of light ends including methane, nitrogen, carbon dioxide (CO.sub.2), or a combination thereof and having a CO.sub.2 multi contact Minimum Miscibility Pressure (CO.sub.2-MMP) below a CO.sub.2-MMP of a native crude oil, wherein the native crude oil is crude oil extracted from the reservoir prior to primary oil recovery therefrom; depleting the pressure of the reservoir from an initial reservoir pressure to the determined depletion pressure, thus providing the lights-depleted crude oil; repressurizing the reservoir to an operating pressure for recovering the lights-depleted crude oil from the reservoir via carbon dioxide (CO.sub.2) injection; injecting CO.sub.2 into the reservoir via at least one injection well; and recovering at least a portion of the lights-depleted crude oil from the reservoir via at least one production well.

The present invention relates to disturbance on hydrate reservoirs with different buried depths, in particularly to a disturbance and stability analysis method for hydrate reservoirs with different buried depths. Preparing a series of stable hydrate systems parallel to a hydrate phase equilibrium curve, wherein both of the porosities and the hydrate saturations of various hydrate systems are consistent, but the buried depths are different; disturbing the series of hydrate systems prepared in the first step, conducting disturbance under different conditions aiming to the hydrate systems with different buried depths; analyzing the stability of the hydrate reservoirs. By controlling the disturbance condition, the hydrate systems with different buried depths may be decomposed along the hydrate phase equilibrium curves thereof or in the hydrate unstable regions; and the decomposition productivity difference between the hydrate reservoirs with different buried depths may be intuitively and scientifically simulated and analyzed.

The present invention relates to disturbance on hydrate reservoirs with different buried depths, in particularly to a disturbance and stability analysis method for hydrate reservoirs with different buried depths. Preparing a series of stable hydrate systems parallel to a hydrate phase equilibrium curve, wherein both of the porosities and the hydrate saturations of various hydrate systems are consistent, but the buried depths are different; disturbing the series of hydrate systems prepared in the first step, conducting disturbance under different conditions aiming to the hydrate systems with different buried depths; analyzing the stability of the hydrate reservoirs. By controlling the disturbance condition, the hydrate systems with different buried depths may be decomposed along the hydrate phase equilibrium curves thereof or in the hydrate unstable regions; and the decomposition productivity difference between the hydrate reservoirs with different buried depths may be intuitively and scientifically simulated and analyzed.

A method of measuring a minimum pressure for gas bubble generation (MPGBG) value of a capillary tube is disclosed. The capillary tube has an inlet and an output portion including an outlet. The inlet is connected to a regulated pneumatic system, configured to supply a gas to the inlet under pressure. The output portion is immersed in a liquid. The gas is supplied to the inlet under a range of pressures including a higher pressure range and a lower pressure range. In the higher pressure range, gas bubbles are generated in the liquid from the outlet. In the lower pressure range, no gas bubbles are generated in the liquid from the outlet. A value of the minimum pressure for gas bubble generation (MPGBG) for the liquid is determined.

Other methods include a method of measuring and storing MPGBG values of capillary tubes, methods of selecting at least one capillary tube from a plurality of capillary tubes, and a method of cutting a capillary tube to a desired MPGBG value.