Determining reserve estimates for a reservoir

1. A method for determining reserve estimates for a reservoir, which comprises:

resampling an attribute grid by matching the attribute grid and a thickness grid so that the attribute grid includes an attribute grid node at each location of a thickness grid node;

creating a unified grid with a plurality of cells and a unified grid node at each location of an attribute grid node; wherein each unified grid node includes a value that is the product of a thickness value of a thickness grid node at a location of the respective unified grid node and an attribute value of a respective resampled attribute grid node at the location of the respective unified grid node;

replacing each invalid value for a respective unified grid node with one of a constant value and an average value;

dividing each cell of the unified grid into four triangles, wherein each of the four triangles includes a vertex at a center of the respective cell and two vertices that form one of four sides of the respective cell;

creating a truncated prism with a volume for each set of four triangles using a computer processor;

adding the volume of each truncated prism together, which represents an Original Oil in Place;

dividing the Original Oil in Place by a Formation Volume Factor, which represents a Stock Tank Original Oil in Place; and

multiplying the Stock Tank Original Oil in Place and a recovery factor, which represents Recoverable Hydrocarbon Reserves.

2. The method of claim 1 , wherein the attribute value represents a value for an attribute from one of porosity, permeability, fluid saturation and net to gross ratio.

3. The method of claim 1 , wherein the resampled attribute grid includes one or more attribute grid nodes with an attribute value that is null.

4. The method of claim 3 , wherein the value of each unified grid node that is the product of the thickness value and a null attribute value is invalid.

5. The method of claim 1 , wherein the average value is determined by dividing a sum of the attribute values for the resampled attribute grid nodes by a total number of resampled attribute grid nodes.

6. The method of claim 1 , wherein the attribute grid is resampled using bicubic interpolation.

7. The method of claim 1 , wherein the constant value is zero.

8. The method of claim 1 , further comprising improving production from the reservoir using the Recovered Hydrocarbon Reserves.

9. The method of claim 1 , wherein each truncated prism is created by connecting each vertex for a respective triangle to a plane including only an x-value and a y-value of the respective vertex at z=0.

10. A non-transitory storage device tangibly carrying computer-executable instructions for determining reserve estimates for a reservoir, the instructions being executable to implement:

resampling an attribute grid by matching the attribute grid and a thickness grid so that the attribute grid includes an attribute grid node at each location of a thickness grid node;

creating a unified grid with a plurality of cells and a unified grid node at each location of an attribute grid node; wherein each unified grid node includes a value that is the product of a thickness value of a thickness grid node at a location of the respective unified grid node and an attribute value of a respective resampled attribute grid node at the location of the respective unified grid node;

replacing each invalid value for a respective unified grid node with one of a constant value and an average value;

dividing each cell of the unified grid into four triangles, wherein each of the four triangles includes a vertex at a center of the respective cell and two vertices that form one of four sides of the respective cell;

creating a truncated prism with a volume for each set of four triangles;

adding the volume of each truncated prism together, which represents an Original Oil in Place;

dividing the Original Oil in Place by a Formation Volume Factor, which represents a Stock Tank Original Oil in Place; and

multiplying the Stock Tank Original Oil in Place and a recovery factor, which represents Recoverable Hydrocarbon Reserves.

11. The storage device of claim 10 , wherein the attribute value represents a value for an attribute from one of porosity, permeability, fluid saturation and net to gross ratio.

12. The storage device of claim 10 , wherein the resampled attribute grid includes one or more attribute grid nodes with an attribute value that is null.

13. The storage device of claim 12 , wherein the value of each unified grid node that is the product of the thickness value and a null attribute value is invalid.

14. The storage device of claim 10 , wherein the average value is determined by dividing a sum of the attribute values for the resampled attribute grid nodes by a total number of resampled attribute grid nodes.

15. The storage device of claim 10 , wherein the attribute grid is resampled using bicubic interpolation.

16. The storage device of claim 10 , wherein the constant value is zero.

17. The storage device of claim 10 , further comprising improving production from the reservoir using the Recovered Hydrocarbon Reserves.

18. The storage device of claim 10 , wherein each truncated prism is created by connecting each vertex for a respective triangle to a plane including only an x-value and a y-value of the respective vertex at z=0.

19. A non-transitory storage device tangibly carrying computer-executable instructions for determining reserve estimates for a reservoir, the instructions being executable to implement:

resampling an attribute grid by matching the attribute grid and a thickness grid so that the attribute grid includes an attribute grid node at each location of a thickness grid node;

creating a unified grid with a plurality of cells and a unified grid node at each location of an attribute grid node; wherein each unified grid node includes a value that is the product of a thickness value of a thickness grid node at a location of the respective unified grid node and an attribute value of a respective resampled attribute grid node at the location of the respective unified grid node;

replacing each invalid value for a respective unified grid node;

dividing each cell of the unified grid into four triangles, wherein each of the four triangles includes a vertex at a center of the respective cell and two vertices that form one of four sides of the respective cell;

creating a truncated prism with a volume for each set of four triangles by connecting each vertex for a respective triangle to a plane including only an x-value and a y-value of the respective vertex at z=0;

adding the volume of each truncated prism together, which represents an Original Oil in Place;

dividing the Original Oil in Place by a Formation Volume Factor, which represents a Stock Tank Original Oil in Place; and

multiplying the Stock Tank Original Oil in Place and a recovery factor, which represents Recoverable Hydrocarbon Reserves.

20. The storage device of claim 19 , further comprising improving production from the reservoir using the Recovered Hydrocarbon Reserves.