Geosteering control framework

A system, comprising:

• one or more processors;
• memory accessible to the one or more processors;
• and
• processor-executable instructions stored in the memory and executable by the one or more processors to instruct the system to:
• receive resistivity data acquired by a downhole tool of a drillstring disposed at least in part in a borehole in a subsurface environment, the borehole comprising a downhole end, the borehole defining a borehole axis;
• receive seismic data for the subsurface environment, the seismic data comprising a plurality of spatial locations;
• perform, in a while-drilling, real-time process, a joint inversion of at least a portion of the resistivity data and at least a portion of the seismic data to estimate, for each of the plurality of spatial locations around and ahead of a drill bit, values for a plurality of physical properties of a portion of the subsurface environment, the plurality of physical properties comprising at least:
• porosity, water saturation, and volume of clay;
• generate reservoir quality metric values for the portion of the subsurface environment, each reservoir quality metric value comprising a reservoir quality indicator (RQ) determined from the estimated porosity, water saturation, and volume of clay using a predefined analytic functional, the predefined analytic functional including RQ=Porosity/(Water Saturation*Volume of Clay);
• and
• control the drillstring in real time using the reservoir quality metric values in an automated control loop, including instructing an autodriller to control one or more of a drawworks, a top drive, a hydraulics system, and a rotary steerable system such that drilling of the borehole is guided by the reservoir quality metric values where an actual direction of the drillstring is directed toward another portion of the subsurface environment having a constant reservoir quality metric value or a higher reservoir quality metric value than a particular reservoir quality metric value of the reservoir quality metric values of the portion of the subsurface environment.

One or more non-transitory computer-readable storage media comprising processor-executable instructions executable to instruct one or more processors to:

• receive resistivity data acquired by a downhole tool of a drillstring disposed at least in part in a borehole in a subsurface environment, the borehole comprising a downhole end, the borehole defining a borehole axis;
• receive seismic data for the subsurface environment, the seismic data comprising a plurality of spatial locations;
• perform, in a while-drilling, real-time process, a joint inversion of at least a portion of the resistivity data and at least a portion of the seismic data to estimate, for each of the plurality of spatial locations around and ahead of a drill bit, values for a plurality of physical properties of a portion of the subsurface environment, the plurality of physical properties comprising at least:
• porosity, water saturation, and volume of clay;
• generate reservoir quality metric values for the portion of the subsurface environment, each reservoir quality metric value comprising a reservoir quality indicator (RQ) determined from the estimated porosity, water saturation, and volume of clay using a predefined analytic functional, the predefined analytic functional including RQ=Porosity/(Water Saturation*Volume of Clay);
• and
• control the drillstring in real time using the reservoir quality metric values in an automated control loop, including instructing an autodriller to control one or more of a drawworks, a top drive, a hydraulics system, and a rotary steerable system such that drilling of the borehole is guided by the reservoir quality metric values where an actual direction of the drillstring is directed toward another portion of the subsurface environment having a constant reservoir quality metric value or a higher reservoir quality metric value than a particular reservoir quality metric value of the reservoir quality metric values of the portion of the subsurface environment.