Avoiding geological formation boundaries during drilling operations

1. A method for avoiding geological formation boundaries during drilling operations, comprising:

determining formation boundaries and formation resistivity;

determining uncertainties and projected uncertainties of the formation boundaries;

determining uncertainties of a drilled well-path;

determining projected uncertainties of a planned well-path;

generating a curtain plot that includes two inverted parameters based on the formation boundaries and the formation resistivity, the uncertainties of the formation boundaries, and the uncertainties of the drilled well-path;

generating an updated curtain plot that includes two projected inverted parameters based on updated formation boundaries and updated formation resistivity, the projected uncertainties of the updated formation boundaries, and the projected uncertainties of the planned well-path;

displaying the curtain plot with the uncertainties of the drilled well-path and the updated curtain plot with the projected uncertainties of the planned well-path;

automatically avoiding, by the drilling operations, the projected uncertainties of the formation boundaries of the curtain plot and the updated curtain plot based on the two inverted parameters and the two projected inverted parameters to maintain or adjust the planned well-path within the projected uncertainties of the planned well-path;

identifying untapped reserves based on the updated curtain plot that includes the two projected inverted parameters; and

calculating reserve estimations based on the untapped reserves for subsequent sidetrack, multi-lateral, or horizontal development.

2. The method of claim 1 , further comprising:

updating one of the curtain plot and the updated curtain plot, in real-time, as the drilled well-path is progressively drilled; and

continuing the avoiding of the projected uncertainties of the formation boundaries until the drilled well-path reaches a final well-path target.

3. The method of claim 1 , wherein the formation resistivity is variable density log data acquired from a logging tool in a high-angle, horizontal, active well.

4. The method of claim 1 , wherein the uncertainties of the formation boundaries and the projected uncertainties of the updated formation boundaries represent three probabilities that match respective formation boundaries.

5. The method of claim 1 , wherein the uncertainties of the formation boundaries of the drilled well-path represent a boundary for the drilled well-path and the projected uncertainties of the updated formation boundaries of the planned well-path represent a boundary for the planned well-path.

6. The method of claim 2 , wherein at least one of the curtain plot and the updated curtain plot includes a well-path target and the final well-path target.

7. The method of claim 1 , wherein the formation resistivity includes data projected from a vertical off-set well.

8. The method of claim 1 , wherein the formation resistivity includes data projected from a resistivity inversion of a layered earth model.

9. A non-transitory program storage device tangibly carrying computer executable instructions for avoiding geological formation boundaries during drilling operations, the instructions being executable to implement:

determining formation boundaries and formation resistivity;

determining uncertainties and projected uncertainties of the formation boundaries;

determining uncertainties of a drilled well-path;

determining projected uncertainties of a planned well-path;

generating a curtain plot that includes two inverted parameters based on the formation boundaries and the formation resistivity, the uncertainties of the formation boundaries, and the uncertainties of the drilled well-path;

generating an updated curtain plot that includes two projected inverted parameters based on updated formation boundaries and updated formation resistivity, the projected uncertainties of the updated formation boundaries, and the projected uncertainties of the planned well-path;

displaying the curtain plot with the uncertainties of the drilled well-path and the updated curtain plot with the projected uncertainties of the planned well-path;

automatically avoiding, by the drilling operations, the projected uncertainties of the formation boundaries of the curtain plot and the updated curtain plot based on the two inverted parameters and the two projected inverted parameters to maintain or adjust the planned well-path within the projected uncertainties of the planned well-path;

identifying untapped reserves based on the updated curtain plot that includes the two projected inverted parameters; and

calculating reserve estimations based on the untapped reserves for subsequent sidetrack, multi-lateral, or horizontal development.

10. The program storage device of claim 9 , further comprising:

updating one of the curtain plot and the updated curtain plot, in real-time, as the drilled well-path is progressively drilled; and

continuing the avoiding of the projected uncertainties of the formation boundaries until the drilled well-path reaches a final well-path target.

11. The program storage device of claim 9 , wherein the formation resistivity is variable density log data acquired from a logging tool in a high-angle, horizontal, active well.

12. The program storage device of claim 9 , wherein the uncertainties of the formation boundaries and the projected uncertainties of the updated formation boundaries represent three probabilities that match respective formation boundaries.

13. The program storage device of claim 9 , wherein the uncertainties of the formation boundaries of the drilled well-path represent a boundary for the drilled well-path and the projected uncertainties of the updated formation boundaries of the planned well-path represent a boundary for the planned well-path.

14. The program storage device of claim 10 , wherein at least one of the curtain plot and the updated curtain plot includes a well-path target and the final well-path target.

15. The program storage device of claim 9 , wherein the formation resistivity includes data projected from a vertical off-set well.

16. The program storage device of claim 9 , wherein the formation resistivity includes data projected from a resistivity inversion of a layered earth model.

17. A non-transitory program storage device tangibly carrying computer executable instructions for avoiding geological formation boundaries during drilling operations, the instructions being executable to implement:

determining formation boundaries and formation resistivity;

determining uncertainties and projected uncertainties of the formation boundaries;

determining uncertainties of a drilled well-path;

determining projected uncertainties of a planned well-path;

generating a curtain plot that includes two inverted parameters based on the formation boundaries and the formation resistivity, the uncertainties of the formation boundaries, and the uncertainties of the drilled well-path;

generating an updated curtain plot that includes two projected inverted parameters based on updated formation boundaries and updated formation resistivity, the projected uncertainties of the updated formation boundaries, and the projected uncertainties of the planned well-path;

displaying the curtain plot with the uncertainties of the drilled well-path and the updated curtain plot with the projected uncertainties of the planned well-path;

automatically avoiding, by the drilling operations, the projected uncertainties of the formation boundaries of the curtain plot and the updated curtain plot based on the two inverted parameters and the two projected inverted parameters to maintain or adjust the planned well-path;

updating one of the curtain plot and the updated curtain plot, in real-time, as the drilled well-path is progressively drilled;

continuing the avoiding of the projected uncertainties of the formation boundaries until the drilled well-path reaches a final well-path target;

identifying untapped reserves based on the updated curtain plot that includes the two projected inverted parameters; and

calculating reserve estimations based on the untapped reserves for subsequent sidetrack, multi-lateral, or horizontal development.

18. The program storage device of claim 17 , wherein the formation resistivity is variable density log data acquired from a logging tool in a high-angle, horizontal, active well.

19. The program storage device of claim 17 , wherein the uncertainties of the formation boundaries and the projected uncertainties of the updated formation boundaries represent three probabilities that match respective formation boundaries.

20. The program storage device of claim 17 , wherein the uncertainties of the formation boundaries of the drilled well-path represent a boundary for the drilled well-path and the projected uncertainties of the updated formation boundaries of the planned well-path, respectively represent a boundary for the planned well-path.