Geosteering control framework

1 . A method, comprising:

receiving 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;

receiving seismic data for the subsurface environment, the seismic data comprising a plurality of spatial locations;

performing, 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;

generating 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

controlling 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.

2 . The method of claim 1 , wherein the seismic data comprises surface seismic data of the subsurface environment.

3 . The method of claim 1 , further comprising performing the joint inversion responsive to the receiving the resistivity data.

4 . The method of claim 3 , further comprising performing the generating responsive to the performing the joint inversion inverting.

5 . The method of claim 4 , further comprising performing the controlling responsive to the performing the generating.

6 . The method of claim 1 , wherein the controlling the drillstring in real time is responsive to the receiving the resistivity data.

7 . The method of claim 1 , wherein the controlling further comprises dynamically adjusting steering parameters based on spatial gradients of the reservoir quality metric values.

8 . The method of claim 1 , further comprising generating uncertainties for the reservoir quality metric values.

9 . The method of claim 1 , further comprising comparing the reservoir quality metric values to one or more pre-determined reservoir quality metric values to determine one or more deviations.

10 . The method of claim 9 , wherein the controlling occurs responsive to at least one of the one or more deviations exceeding a deviation threshold.

11 . The method of claim 1 , wherein the seismic data comprises synthetic seismic data.

12 . The method of claim 1 , further comprising:

providing productivity index values for the portion of the subsurface environment, the productivity index values representing productivity of the portion of the subsurface environment;

assessing the productivity index values with respect to the reservoir quality metric values; and

performing the controlling based at least in part on the assessing.

13 . The method of claim 12 , wherein the performing the controlling comprises directing the drillstring to maintain productivity of the borehole.

14 . The method of claim 1 , wherein the joint inversion is performed using a machine learning model trained on a dataset of known reservoir properties and corresponding resistivity and seismic data.

15 . The method of claim 1 , wherein the reservoir quality metric values are used to control the drillstring in real-time to avoid drilling into a new portion of the subsurface environment having a lower reservoir quality metric value than the reservoir quality metric value of the portion of the subsurface environment.

16 . The method of claim 1 , wherein the joint inversion is performed using a combination of seismic data and resistivity data acquired by a plurality of downhole tools, including at least one tool located behind the drill bit and at least one tool located ahead of the drill bit.

17 . 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.

18 . 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.