The broad departure between the BHGM and gamma-gamma density logs in this Michigan reef example reveals the edge of the reef complex is within a few hundred feet of the well. The overlying low-density zone near the top of the log is salt. The sharp difference in density at the arrow is caused by a remote higher [[porosity]] zone not detected by the gamma-gamma density log. The broader difference anomaly observed over the length of the interval is explained by the influence of the entire reef complex. | The broad departure between the BHGM and gamma-gamma density logs in this Michigan reef example reveals the edge of the reef complex is within a few hundred feet of the well. The overlying low-density zone near the top of the log is salt. The sharp difference in density at the arrow is caused by a remote higher [[porosity]] zone not detected by the gamma-gamma density log. The broader difference anomaly observed over the length of the interval is explained by the influence of the entire reef complex. |