Lithology refers to the macroscopic nature of the mineral content, grain size, texture, and colour of rocks. All lithologies (both reservoirs and non-reservoirs) defined in the loaded trend file will be displayed in this tab. The Vp, Vs, density, and porosity (whenever applicable) of individual lithology loaded from the trend file can be viewed by scrolling the lithology information.

Non-reservoir lithologies are not always entirely pure. It is possible to have a mix of different non-reservoir lithologies in a given rock layer. Therefore, adding non-reservoir composites into the QI Stochastic Model window may provide a better estimation and analysis of the probabilities that could occur. Some examples of non-reservoir such as shale, coal, high-velocity shale or high-density shale can be mixed to create a probable composite. 

Similar to creating a composite fluid, the QI Stochastic Model window allows the creation of a simple composite lithology of two non-reservoir lithologies, subsequently forward modelling the composite as a new distinct composite lithology.