부산대학교 도서관

Eleven wells in Olsego, Ogemaw, and Sanilac Counties, Michigan were analyzed by use of the Antrim Shale specific log analysis model, and showed average porosities in each of three Antrim Shale Units (Lachine, Paxton, Norwood Shales) were constant for each unit in the three counties. The Norwood has the highest average porosity and the Paxton has the lowest. The Norwood Shale has the highest bulk volume hydrocarbons (BVH), whereas those values in the Lachine and Paxton are lower. The high BVH values for the Ogemaw County wells were not reflected in gas production rates, and commercial rates of gas production are not tied to the reservoir properties of: porosity, volume hydrocarbons, water saturation, formation resistivity, kerogen volume, and bulk volume of water. Enhanced formation image analysis techniques showed that the abundance of open and partially open fractures, as well as fracture intersections in the Lachine and Norwood Shales, are controlling factors for gas production. Fractures were mapped with respect to the borehole in 12 wells in the three counties. A fracture factor Z(sub f) was plotted against average gas production rates (Q) for eight Olsego County wells and one Ogemaw County well, and a relationship between the two may be established.