Systems and methods for generating continuous grain size logs from petrographic thin section images

Systems and methods for determining a continuous grain size log from a collection of petrographic thin section images are provided. Thin section images from core samples from one or more wells may be obtained and analyzed to estimate grain sizes. Using wireline logs from the one or more wells and the estimated grain sizes, a data structure (for example, a database) of grain sizes and wireline logs at depths may be constructed. The data structure may be used to train a machine learning model. Next, a wireline tool may be used to obtain wireline logs in a new well, and a continuous grain size log may be determined from the wireline logs of using the machine learning model. Computer-readable media for determining reservoir rock grain sizes from a collection of petrographic thin section images is also provided.