Это переводится "черновая модель" или как-то иначе?

Выражение встречается в следующем контексте:
"A petrophysical bulk model of the target formations is the main prerequisite for reliable discrimination of formations in the elastic properties domain and for the selection of the type of seismic inversion. The model is based on the results of core descriptions and drill cuttings, as well as on the interpretation of well logs."

Заранее спасибо.