Identifying unconformities in subsurface formations

A system for identifying unconformities in a subsurface formation, the system comprising:

• at least one processor;
• and
• a memory storing instructions that, when executed by the at least one processor, cause the at least one processor to perform operations comprising:
• accessing, from a data store, well log measurements from a set of wells in the subsurface formation, the well log measurements comprising gamma ray logs, porosity logs, and borehole image logs;
• accessing, from a data store, core sample data from a first subset of the set of wells;
• identifying a second subset of the set of wells including wells without lithology contrast based on the gamma ray logs and the porosity logs;
• characterizing fractures and bedding planes in the borehole image logs for wells in the second subset;
• for wells included in the first subset and the second subset:
• determining a location of the unconformity in the wells based on the core sample data;
• generating correlations between the determined location of the unconformity based on the core sample data and the identified fractures and bedding planes in the borehole image logs;
• for wells included in the second subset and not included in the first subset:
• determining the location of the unconformity in the wells based on the identified fractures and bedding planes and based on the generated correlations;
• and
• generating an unconformity surface based on the determined locations of the unconformity from the set of wells.

One or more non-transitory machine-readable storage devices storing instructions for identifying unconformities in a subsurface formation, the instructions being executable by one or more processors, to cause performance of operations comprising:

• accessing, from a data store, well log measurements from a set of wells in the subsurface formation, the well log measurements comprising gamma ray logs, porosity logs, and borehole image logs;
• accessing, from a data store, core sample data from a first subset of the set of wells;
• identifying a second subset of the set of wells including wells without lithology contrast based on the gamma ray logs and the porosity logs;
• characterizing fractures and bedding planes in the borehole image logs for wells in the second subset;
• for wells included in the first subset and the second subset:
• determining a location of the unconformity in the wells based on the core sample data;
• generating correlations between the determined location of the unconformity based on the core sample data and the identified fractures and bedding planes in the borehole image logs;
• for wells included in the second subset and not included in the first subset:
• determining the location of the unconformity in the wells based on the identified fractures and bedding planes and based on the generated correlations;
• and
• generating an unconformity surface based on the determined locations of the unconformity from the set of wells.