Geologic models of subsurface sedimentary volumes

A method for constructing a geologic model of a subsurface volume, the method comprising:

• (a) identifying at least one outline form of a potential geologic body from geologic data pertaining to the subsurface volume;
• (b) selecting from the identified at least one outline form only the at least one outline form likely to correspond to sand-prone geologic bodies;
• (c) adjusting the at least one outline form of the potential geologic body to make the potential geologic body substantially consistent with additional constraints on body properties;
• (d) estimating, using a computer, a grain size distribution within at least a portion of the potential geologic body, guided by the at least one outline form of the potential geologic body;
• (e) estimating rock properties within at least a portion of the potential geologic body based on the grain size distribution.

A method for constructing a model of a subsurface volume comprising:

• (a) identifying an outline form of at least one geologic body from seismic data pertaining to the subsurface volume;
• (b) estimating, using a computer, a depositing flow field that created the at least one geologic body from the outline form;
• (c) estimating grain size distribution within at least part of the at least one geologic body using a relationship between an estimated flow field that created the at least one geologic body and the grain size distribution;
• (d) estimating rock properties of a sedimentary basin within at least part of the subsurface volume based on the grain size distribution.