Imaging a subsurface geological model at a past intermediate restoration time

A system for restoring a 3D model of the subsurface geology of the Earth from a present day geometry measured at a present time to a predicted past geometry at a past restoration time, the system comprising:

• one or more processors configured to:
• receive the 3D model of the present day measured geometry comprising a network of faults, wherein a fault is a discontinuity that divides fault blocks that slide in opposite directions tangential to the surface of the fault as time approaches a modeled time,
• select a past restoration time τ that is prior to the present time and after a time when an oldest horizon surface in the 3D model was originally deposited,
• divide the network of faults into a subset of τ-active faults and a subset of τ-inactive faults, wherein a τ-active fault is a fault that is active at the past restoration time τ and a τ-inactive fault is a fault that is inactive at the past restoration time τ, wherein the one or more processors determine a fault to be τ-active when the fault intersects a horizon Hτ that was originally deposited at the past restoration time τ and determine a fault to be τ-inactive when the fault does not intersect the horizon Hτ that was originally deposited at the past restoration time τ,
• restore the 3D model from the present day measured geometry to the predicted past geometry at the past restoration time τ by:
• modeling each τ-active fault to join end points of a horizon Hτ separated on opposite sides of the fault in the present day model to merge into the same position in the restored model by sliding the end points towards each other in a direction tangential to the surface of the τ-active fault, and
• modeling each τ-inactive fault to keep collocated points on opposite sides of the fault together.