System and method for preventing collisions in wellbores

1 . A method of preventing a collision of a subject wellbore in a downhole environment, comprising:

receiving offset wellbore data corresponding with one or more offset wellbores, the offset wellbore data indicating, for each of the one or more offset wellbores, an offset trajectory for the one or more offset wellbores;

identifying, based on the offset wellbore data, a plurality of no-go zones including at least one no-go zone for each of the one or more offset wellbores, wherein, for each offset wellbore of the one or more offset wellbores, the at least one no-go zone indicates a threshold uncertainty of an expected location of the offset trajectory for the one or more offset wellbores at one or more measurement depths;

generating a traveling cylinder plot for the subject wellbore that projects ahead of the subject wellbore a projection distance, the traveling cylinder plot having a coordinate system with an origin and indicating, across the projection distance, the at least one no-go zone for each of the one or more offset wellbores in the coordinate system;

determining, based on the traveling cylinder plot, a plurality of safe points, each safe point of the plurality of safe points associated with a segment of a plurality of segments of the traveling cylinder plot, wherein each segment of the plurality of segments comprises a line from the origin to a perimeter of the traveling cylinder plot, and wherein determining the plurality of safe points comprises, for each segment:

determining a plurality of candidate safe points based on intersections of the segment with a boundary of the plurality of no-go zones; and

selecting a segment safe point for the plurality of safe points, the segment safe point including a closest candidate safe point from the plurality of candidate safe points, wherein the closest candidate safe point is closest to the origin;

generating an escape zone by defining a plurality of tolerance lines between adjacent safe points of the plurality of safe points, the adjacent safe points associated with adjacent segments of the plurality of segments;

determining a trajectory for the subject wellbore that does not intersect the one or more offset wellbores, wherein the trajectory is generated within the escape zone; and

steering a downhole tool to implement the trajectory and to form the subject wellbore to avoid collisions with the one or more offset wellbores.

2 . The method of claim 1 , further comprising receiving lease line data corresponding with a geographical boundary for the subject wellbore to be drilled, wherein the escape zone is further defined based on the lease line data.

3 . The method of claim 1 , wherein determining the trajectory includes determining the trajectory based on an observed user preference from past trajectory determinations.

4 . The method of claim 1 , wherein the method is performed while drilling the subject wellbore.

5 . The method of claim 1 , further comprising updating the offset wellbore data for at least one wellbore of the one or more offset wellbores based on a validation of the offset wellbore data during drilling of the subject wellbore.

6 . The method of claim 5 , wherein updating the offset wellbore data includes adjusting the at least one no-go zone for the at least one wellbore of the one or more offset wellbores.

7 . The method of claim 1 , wherein the coordinate system of the traveling cylinder plot is a 2-dimensional coordinate system that represents a proximity of the one or more offset wellbores to the subject wellbore at a plurality of depths.

8 . The method of claim 1 , further comprising determining a collision risk associated with the trajectory.

9 . The method of claim 8 , wherein the collision risk is associated with a proximity of the trajectory with a boundary of the escape zone.

10 . The method of claim 1 , wherein determining the trajectory includes:

determining a plurality of candidate trajectories within the escape zone;

determining a plurality of collision risks, each collision risk associated with an associated candidate trajectory of the plurality of candidate trajectories, wherein the plurality of collision risks are based on a proximity of the associated candidate trajectory of the plurality of candidate trajectories with an escape zone boundary of the escape zone; and

selecting the trajectory from the plurality of candidate trajectories based on the plurality of collision risks associated with the plurality of candidate trajectories.

11 . The method of claim 10 , wherein selecting the trajectory includes selecting the trajectory based on a lowest collision risk of the plurality of collision risks.

12 . The method of claim 10 , wherein selecting the trajectory includes selecting the trajectory based on the trajectory being associated with a selected collision risk of the plurality of collision risks that is within a collision risk threshold.

13 . The method of claim 10 , wherein selecting the trajectory is based on a cost function incorporating a plurality of factors, the plurality of factors including the plurality of collision risks.

14 . A system, comprising:

one or more processors;

a memory in electronic communication with the one or more processors; and

instructions stored in the memory, the instructions being executable by the one or more processors to:

receive offset wellbore data corresponding with one or more offset wellbores, the offset wellbore data indicating, for each of the one or more offset wellbores, an offset trajectory for the one or more offset wellbores;

identify, based on the offset wellbore data, a plurality of no-go zones including at least one no-go zone for each of the one or more offset wellbores, wherein, for each offset wellbore of the one or more offset wellbores, the at least one no-go zone indicates a threshold uncertainty of an expected location of the offset trajectory for the one or more offset wellbores at one or more measurement depths;

generate a traveling cylinder plot for a subject wellbore that projects ahead of the subject wellbore a projection distance, the traveling cylinder plot having a coordinate system with an origin and indicating, across the projection distance, the at least one no-go zone for each of the one or more offset wellbores in the coordinate system;

determine, based on the traveling cylinder plot, a plurality of safe points, each safe point of the plurality of safe points associated with a segment of a plurality of segments of the traveling cylinder plot, wherein each segment of the plurality of segments comprises a line from the origin to a perimeter of the traveling cylinder plot, and wherein determining the plurality of safe points comprises, for each segment:

determining a plurality of candidate safe points based on intersections of the segment with a boundary of the plurality of no-go zones; and

selecting a segment safe point for the plurality of safe points, the segment safe point including a closest candidate safe point from the plurality of candidate safe points, wherein the closest candidate safe point is closest to the origin;

generate an escape zone by defining a plurality of tolerance lines between adjacent safe points of the plurality of safe points, the adjacent safe points associated with adjacent segments of the plurality of segments;

determine a trajectory for the subject wellbore that does not intersect the one or more offset wellbores, wherein the trajectory is generated within the escape zone; and

steer a downhole tool to implement the trajectory and to form the subject wellbore to avoid collisions with the one or more offset wellbores.

15 . A computer-readable storage medium including instruction that, when executed by at least one processor, cause the processor to:

receive offset wellbore data corresponding with one or more offset wellbores, the offset wellbore data indicating, for each of the one or more offset wellbores, an offset trajectory for the one or more offset wellbores;

identify, based on the offset wellbore data, a plurality of no-go zones including at least one no-go zone for each of the one or more offset wellbores, wherein, for each offset wellbore of the one or more offset wellbores, the at least one no-go zone indicates a threshold uncertainty of an expected location of the offset trajectory for the one or more offset wellbores at one or more measurement depths;

generate a traveling cylinder plot for a subject wellbore that projects ahead of the subject wellbore a projection distance, the traveling cylinder plot having a coordinate system with an origin and indicating, across the projection distance, the at least one no-go zone for each of the one or more offset wellbores in the coordinate system;

determine, based on the traveling cylinder plot, a plurality of safe points, each safe point of the plurality of safe points associated with a segment of a plurality of segments of the traveling cylinder plot, wherein each segment of the plurality of segments comprises a line from the origin to a perimeter of the traveling cylinder plot, and wherein determining the plurality of safe points comprises, for each segment:

determining a plurality of candidate safe points based on intersections of the segment with a boundary of the plurality of no-go zones; and

selecting a segment safe point for the plurality of safe points, the segment safe point including a closest candidate safe point from the plurality of candidate safe points, wherein the closest candidate safe point is closest to the origin;

generate an escape zone by defining a plurality of tolerance lines between adjacent safe points of the plurality of safe points, the adjacent safe points associated with adjacent segments of the plurality of segments;

determine a trajectory for the subject wellbore that does not intersect the one or more offset wellbores, wherein the trajectory is generated within the escape zone; and

steer a downhole tool to implement the trajectory and to form the subject wellbore to avoid collisions with the one or more offset wellbores.

16 . The method of claim 1 , further comprising:

while performing drilling activities, iteratively receiving additional offset wellbore data;

while performing the drilling activities, iteratively updating the traveling cylinder plot with the additional offset wellbore data;

while performing the drilling activities, iteratively generating an updated escape zone using the updated traveling cylinder plot;

while performing the drilling activities, iteratively generating an updated trajectory by comparing the trajectory to the updated escape zone; and

steering the downhole tool to implement the updated trajectory.