Seismic Wellbore Positioning Using Offset Sources

The patent introduces seismic energy sources and receivers as intermediary elements to determine wellbore position. Instead of relying directly on gyroscopic or magnetic/gravitational sensors in the wellbore, the system uses seismic sources positioned in offset wellbores or on the surface, which generate seismic waves that propagate through the subsurface. Receivers in the drilling wellbore detect these waves, and the position is calculated based on travel times and wave characteristics. This intermediary seismic measurement approach maintains accuracy over greater lateral distances compared to direct surveying methods.

The patent replaces the mechanical/gyroscopic surveying system with a seismic wave-based measurement system. Instead of using gyroscopes or magnetic/gravitational sensors that suffer from accuracy degradation over distance, the system uses seismic energy propagation and detection. The position determination is based on analyzing seismic wave travel times, velocities, and phases rather than mechanical rotation or magnetic field measurements, thereby substituting a physics-based acoustic method for the traditional mechanical surveying approach.

The patent segments the positioning problem into multiple independent seismic measurements. Instead of relying on a single continuous survey measurement that degrades with distance, the system uses multiple discrete seismic sources positioned at different locations (in offset wellbores or on the surface) and multiple receivers in the drilling wellbore. Each source-receiver pair provides an independent measurement of wellbore position, and the final position is determined by combining these multiple measurements. This segmentation approach improves reliability by providing redundant measurements that can be cross-validated and by not depending on a single measurement path.

The patent uses seismic waves as an intermediary medium to transfer position information from the wellbore to the surface measurement system. The seismic sources generate waves that propagate through the subsurface rock formations, carrying information about the wellbore position. Receivers detect these waves, and the travel time and wave characteristics serve as intermediaries that allow calculation of the wellbore position without requiring direct line-of-sight or continuous mechanical connection to the surface. This intermediary approach maintains reliability over greater lateral distances where direct surveying methods fail.

The patent makes the seismic measurement system multi-functional to justify the increased deployment complexity. The same seismic sources and receivers used for wellbore position determination can also be used for reservoir characterization, seismic imaging, and other subsurface exploration tasks. The seismic sources can be positioned in offset wellbores that may already exist for production or injection purposes, and the receivers can be integrated into the drilling equipment or deployed in existing wellbores. This multi-functionality allows the system to provide multiple benefits from a single deployment, offsetting the operational complexity through additional value.

The patent employs self-service approaches in the seismic measurement system. The seismic sources are positioned in offset wellbores or on the surface using existing infrastructure, eliminating the need to drill dedicated survey wellbores. The receivers in the drilling wellbore can be integrated into the drilling equipment itself, so the same equipment used for drilling also performs the seismic measurements. The system uses the subsurface rock formations themselves as the propagation medium, requiring no additional infrastructure. This self-service approach reduces operational complexity by utilizing existing resources and infrastructure rather than requiring dedicated survey equipment and infrastructure.