Pyrolysis to determine hydrocarbon expulsion efficiency of hydrocarbon source rock
An open system pyrolysis of a first hydrocarbon source rock sample obtained from a natural system is performed within a pyrolysis chamber by maintaining the pyrolysis chamber at a substantially constant temperature. Hydrocarbons are recovered from the pyrolysis chamber released by the first hydrocarbon source rock sample. A thermo-vaporization is performed within the pyrolysis chamber on the pyrolyzed sample at a substantially constant temperature. A first hydrocarbon expulsion efficiency of hydrocarbon source rock is determined. A second hydrocarbon rock sample is ground to a grain size less than or equal to or less than 250 micrometers. A second pyrolysis is performed on the ground hydrocarbon source rock sample by maintaining the chamber at a substantially constant temperature. A second hydrocarbon expulsion efficiency of the hydrocarbon source rock in the natural system is determined. The first hydrocarbon expulsion efficiency is verified using the second hydrocarbon expulsion efficiency.
1. A method comprising:
performing an open system pyrolysis, within a pyrolysis chamber, on a hydrocarbon source rock sample comprising fragments having an equivalent spherical diameter of substantially at least one centimeter, performing the open system pyrolysis resulting in a pyrolyzed rock sample;
recovering hydrocarbons released by the rock sample in response to the open system pyrolysis;
determining a first quantity of hydrocarbons released in response to the open system pyrolysis;
performing a thermo-vaporization within the pyrolysis chamber on the pyrolyzed rock sample;
recovering hydrocarbons released by the rock sample in the pyrolysis chamber in response to the thermo-vaporization;
determining a second quantity of hydrocarbons released in response to thermo-vaporization in the pyrolysis chamber;
placing the sample in a crushing chamber and crushing and performing thermo-vaporization on the pyrolyzed rock sample;
recovering hydrocarbons released by the rock sample in response to crushing and thermo-vaporization;
determining a third quantity of hydrocarbons released in response to crushing and thermo-vaporization in the crushing chamber;
determining a first hydrocarbon expulsion efficiency of the hydrocarbon source rock as a ratio of a sum of the first quantity of hydrocarbons to a sum of the first quantity of hydrocarbons, the second quantity of hydrocarbons, and the third quantity of hydrocarbons;
pyrolyzing a powdered sample of the hydrocarbon source rock having a grain size less than or equal to substantially 250 microns;
determining a fourth quantity of hydrocarbons released in response to performing open system pyrolysis on the powdered sample;
determining a second hydrocarbon expulsion efficiency of the hydrocarbon source rock as a ratio of the first quantity of hydrocarbons to the fourth quantity of hydrocarbons;
and providing the first or the second hydrocarbon expulsion efficiency as an input to a geological model configured to analyze a hydrocarbon expulsion from the hydrocarbon source rock through geological history.