Gridless volumetric computation

1 . A method for computing, by a volume data processor, volumetrics of a subsurface region without gridlines associated with the subsurface region, comprising:

creating, in the volume data processor, a geometry representing the subsurface region and a first bounding box about the geometry;

computing a first probability that a group of sampled points inside the first bounding box are inside the geometry; and

computing a gross rock volume (GRV) of the geometry by multiplying the first probability by a volume of the first bounding box.

2 . The method of claim 1 further comprising:

determining a quantity of points in the group of sampled points that will satisfy a precision based on a confidence level and the first probability.

3 . The method of claim 1 , further comprising:

creating, in the volume data processor, a second geometry representing a subregion of the subsurface region and second bounding box about the second geometry;

computing a second probability that a group of sampled points inside the second bounding box are also inside the second geometry; and

computing a subregion GRV by multiplying the second probability by a volume of the second bounding box.

4 . The method of claim 3 further comprising:

computing a pore volume of the subsurface region by multiplying the GRV by an average porosity of the geometry.

5 . The method of claim 4 further comprising:

computing the average porosity of the geometry via Turning Band simulation or a Sequential Gaussian simulation.

6 . The method of claim 4 further comprising:

computing a net pore volume (NPV) of the subregion by multiplying the subregion GRV by an average porosity of the subregion and by an average net-to-gross function value for the subregion.

7 . The method of claim 4 further comprising:

computing an original oil in place (OOIP) of the subregion by multiplying the second probability by the volume of the second bounding box; and

multiplying an average porosity of the subregion by an average net-to-gross function value for the subregion and by a hydrocarbon saturation of the subregion.

8 . A volume data processor comprising program code configured to compute volumetrics of a subsurface region without gridlines associated with the subsurface region, the program code executable on one or more processors, the program code comprising:

instructions to create, in the volume data processor, a geometry representing the subsurface region and a first bounding box about the geometry;

instructions to compute a first probability that a group of sampled points inside the first bounding box are inside the geometry; and

instructions to compute a gross rock volume (GRV) of the geometry by multiplying the first probability by a volume of the first bounding box.

9 . The volume data processor of claim 8 further comprising:

instructions to create, in the volume data processor, a second geometry representing a subregion of the subsurface region and second bounding box about the second geometry;

instructions to compute a second probability that a group of sampled points inside the second bounding box are also inside the second geometry; and

instructions to compute a subregion GRV by multiplying the second probability by a volume of the second bounding box.

10 . The volume data processor of claim 9 further comprising:

instructions to compute a pore volume of the subsurface region by multiplying the GRV by an average porosity of the geometry.

11 . The volume data processor of claim 10 further comprising:

instructions to compute the average porosity of the geometry via Turning Band simulation or a Sequential Gaussian simulation.

12 . The volume data processor of claim 10 further comprising:

instructions to compute a net pore volume (NPV) of the subregion by multiplying the subregion GRV by an average porosity of the subregion and by an average net-to-gross function value for the subregion.

13 . The volume data processor of claim 10 further comprising:

instructions to compute an original oil in place (OOIP) of the subregion by multiplying the second probability by the volume of the second bounding box; and

instructions to multiply an average porosity of the subregion by an average net-to-gross function value for the subregion and by a hydrocarbon saturation of the subregion.

14 . One or more non-transitory, machine-readable media including program code configured to compute volumetrics of a subsurface region without gridlines associated with the subsurface region, the program code executable by a volume data processor, the program code comprising:

instructions to create, in the volume data processor, a geometry representing the subsurface region and a first bounding box about the geometry;

instructions to compute a first probability that a group of sampled points inside the first bounding box are inside the geometry; and

instructions to compute a gross rock volume (GRV) of the geometry by multiplying the first probability by a volume of the first bounding box.

15 . The machine-readable media of claim 14 further comprising:

instructions to create, in the volume data processor, a second geometry representing a subregion of the subsurface region and second bounding box about the second geometry;

instructions to compute a second probability that a group of sampled points inside the second bounding box are also inside the second geometry; and

instructions to compute a subregion GRV by multiplying the second probability by a volume of the second bounding box.

16 . The machine-readable media of claim 15 further comprising:

instructions to compute a pore volume of the subsurface region by multiplying the GRV by an average porosity of the geometry.

17 . The machine-readable media of claim 16 further comprising:

instructions to compute the average porosity of the geometry via Turning Band simulation or a Sequential Gaussian simulation.

18 . The machine-readable media of claim 16 further comprising:

instructions to compute a net pore volume (NPV) of the subregion by multiplying the subregion GRV by an average porosity of the subregion and by an average net-to-gross function value for the subregion.

19 . The machine-readable media of claim 16 further comprising:

instructions to compute an original oil in place (OOIP) of the subregion by multiplying the second probability by the volume of the second bounding box; and

instructions to multiply an average porosity of the subregion by an average net-to-gross function value for the subregion and by a hydrocarbon saturation of the subregion.

20 . The machine-readable media of claim 14 further comprising:

instructions to determine a quantity of points in the group of sampled points that will satisfy a precision based on a confidence level and the first probability.