Methods and apparatus for collecting and preserving core samples from a reservoir
Provided herein are methods and apparatus for collecting and preserving core samples from a reservoir. In some embodiments, a method includes obtaining core samples from a reservoir using a rock and fluid sampling tool and depositing the core samples in a vessel filled with a hydrogen-free fluid such that a portion of the hydrogen-free fluid is displaced by the core samples and the core samples are immersed in the hydrogen-free fluid. The method also includes transferring a gas into the vessel to occupy a space in the vessel and sealing the vessel via a cap on an end of the vessel. Methods of analyzing the core samples core samples collected from a reservoir and a rock and fluid sampling tool are also provided.
1. A method of analyzing core samples collected from a reservoir, comprising:
providing a pressurized vessel comprising one or more core samples immersed in a hydrogen-free fluid, the pressurized vessel sealed downhole in a wellbore extending into a reservoir after collecting the one or more core samples from the reservoir, the pressurized vessel comprising a gas;
heating the pressurized vessel to a temperature value;
reducing, in one or more steps, a pressure of the pressurized vessel to atmospheric pressure, each step comprising:
releasing an amount of the gas, an amount of the hydrogen-free fluid, an amount of hydrocarbons, or any combination thereof, to reduce the pressure of the pressurized vessel by a pressure value; and
determining the released amount of the gas, the released amount of the hydrogen-free fluid, the released amount of the hydrocarbons, or any combination thereof;
determining, after reducing the pressure of the pressurized vessel to atmospheric pressure, a total amount of the gas, the hydrogen-free fluid, and the hydrocarbons released; and
calculating a hydrocarbons-in-place value based on the total amount of the gas, the hydrogen-free fluid, and the hydrocarbons released.
2. The method of claim 1 , wherein the temperature value is substantially equal to a temperature of the reservoir.
3. The method of claim 1 , wherein the pressure value is a first pressure value, the method comprising pressuring the pressurized vessel to a second pressure value before reducing, in one or more steps, the pressure of the pressurized vessel to atmospheric pressure.
4. The method of claim 3 , wherein the second pressure value is substantially equal to a pressure of the reservoir.
5. The method of claim 1 , wherein the hydrogen-free fluid comprises a fluorocarbon-based fluid.
6. The method of claim 1 , wherein the gas comprises nitrogen.
7. The method of claim 1 , wherein the vessel comprises a eutectic metal component.