ABSTRACT

The Innes Field is one of several oilfields within the Frobisher trend in southeastern Saskatchewan. The fields produce from, and lie within, the subcrop trace of the Frobisher Beds.

The Frobisher Beds of the study area can be subdivided into four marker defined stratigraphic units. Each unit contains at least two of four major rock types: oolitic-pelletoidal packstone, skeletal packstone, argillaceous microsucrosic dolomite and sucrosic dolomite.

The lithologies and porosity types of the Innes field sugest that the Frobisher lithofacies were deposited in a subtidal-intertidal environment. The Frobisher deposits are similar to those of the Quaternary bank in Shark Bay, Western Australia, where a carbonate bank with a wedge-shaped cross-section has been accreted onto the periphery of a shallow marine basin. In addition, evidence suggests the presence of three tidal channels transecting the carbonate bank in the Innes area during Frobisher time. Frobisher channel-fill and levee deposits occur in a narrow southwest-northeast trend across the northwestern portion of the field.

At least six hydrocarbon pools, which vary in area from 120 to 480 hectares, produce from the Frobisher interval at Innes. A stratified reservoir system exists within the main producing structure, and the pools are sealed updip at the sub-Mesozoic unconformity.