Abstract: A method for determining a phase-state type and saturation of a fluid by an NMR technology includes putting a core to be measured to an NMR phase-state testing device, injecting a heavy water solution from both ends of a gripper at the same time until the core reaches the formation pressure, and stopping; scanning the core to obtain a two-dimensional NMR map, and determining whether the core contains a gas phase; reducing the temperature of the gripper, and collecting an oil phase volume, a gas phase volume and a water phase volume discharged from the core; purge the pipelines out with nitrogen, collecting a water phase volume and an oil phase volume in the pipelines; performing dry distillation on the core to obtain an oil phase volume and a water phase volume; and obtaining the saturations of various phases according to the fluid volumes of multiple phases in the core.

Abstract: The present invention discloses a gas based testing method for a pore volume compressibility of a low-permeability rock. The method comprises the following steps: obtaining a compressibility and an isothermal adsorption-desorption curve of experimental gas under a reservoir condition; performing a physical simulation experiment by using a steel core drilled with a through hole, and obtaining a gas volume collected due to the deformation of an experimental instrument; then repeating the experiment by using an actual core with the same size, and obtaining pore volumes of the reservoir core under the experimental conditions by deducting deformation of the instrument; and finally, obtaining a pore compressibility of the reservoir core under different reservoir conditions according to the pore volumes of the reservoir core under different reservoir conditions. The present invention considers gas adsorption, corrects errors caused by deformation of a physical simulation device.

Abstract: A method for determining a phase-state type and saturation of a fluid by an NMR technology includes putting a core to be measured to an NMR phase-state testing device, injecting a heavy water solution from both ends of a gripper at the same time until the core reaches the formation pressure, and stopping; scanning the core to obtain a two-dimensional NMR map, and determining whether the core contains a gas phase; reducing the temperature of the gripper, and collecting an oil phase volume, a gas phase volume and a water phase volume discharged from the core; purge the pipelines out with nitrogen, collecting a water phase volume and an oil phase volume in the pipelines; performing dry distillation on the core to obtain an oil phase volume and a water phase volume; and obtaining the saturations of various phases according to the fluid volumes of multiple phases in the core.