Parametric attribute of pore volume of subsurface structure from structural depth map

A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform operations comprising:

• receiving a plurality of data points corresponding to a first reservoir unit at a site, wherein the site is for hydrocarbon exploration or CO2 sequestration, each data point comprises two elements, one of the two elements represents a depth of a respective location on a structure depth map of the first reservoir unit, and another of the two elements represents a volume that is enclosed by the structure depth map and that is between the respective location on the structure depth map of the first reservoir unit and a closing contour of the first reservoir unit;
• curve fitting a function to the plurality of data points corresponding to the first reservoir unit at the site, wherein the function represents a functional relationship between a gross rock volume (GRV) of the first reservoir unit at the site and a closure height of the first reservoir unit, the closure height of the first reservoir unit is a height from a crest of the first reservoir unit to the closing contour of the first reservoir unit, the crest of the first reservoir unit is a shallowest point of the first reservoir unit that is retaining hydrocarbons or a fluid that is positively buoyant relative to water, and the GRV of the first reservoir unit is truncated at the closing contour of the first reservoir unit, the functional relationship defining a plurality of isopachous surfaces at the site;
• determining a respective GRV of each of a plurality of reservoir units at the site using the function;
• determining a total GRV of the plurality of reservoir units at the site to be a sum of the determined respective GRV of each of the plurality of reservoir units;
• and
• performing CO2 sequestration at the site using the determined total GRV of the plurality of reservoir units at the site.

A computer-implemented system, comprising:

• one or more computers;
• and
• one or more computer memory devices interoperably coupled with the one or more computers and having tangible, non-transitory, machine-readable media storing one or more instructions that, when executed by the one or more computers, perform one or more operations comprising:
• receiving a plurality of data points corresponding to a first reservoir unit at a site, wherein the site is for hydrocarbon exploration or CO2 sequestration, each data point comprises two elements, one of the two elements represents a depth of a respective location on a structure depth map of the first reservoir unit, and another of the two elements represents a volume that is enclosed by the structure depth map and that is between the respective location on the structure depth map of the first reservoir unit and a closing contour of the first reservoir unit;
• curve fitting a function to the plurality of data points corresponding to the first reservoir unit at the site, wherein the function represents a functional relationship between a gross rock volume (GRV) of the first reservoir unit at the site and a closure height of the first reservoir unit, the closure height of the first reservoir unit is a height from a crest of the first reservoir unit to the closing contour of the first reservoir unit, the crest of the first reservoir unit is a shallowest point of the first reservoir unit that is retaining hydrocarbons or a fluid that is positively buoyant relative to water, and the GRV of the first reservoir unit is truncated at the closing contour of the first reservoir unit, the functional relationship defining a plurality of isopachous surfaces at the site;
• determining a respective GRV of each of a plurality of reservoir units at the site using the function;
• determining a total GRV of the plurality of reservoir units at the site to be a sum of the determined respective GRV of each of the plurality of reservoir units;
• and
• performing CO2 sequestration screening of at the site using the determined total GRV of the plurality of reservoir units at the site.