A method of completing a hydrocarbon lateral well in a target shale formation. The method uses a data log generated from an optical flow cell assembly to identify areas in the lateral well of high free gas porosity. By evaluating such data, an operator can group “like” rock, determine stage length and variation in stage length, and determine perforation cluster spacing and location. The flow cell assembly can also be used in a completion program to assist in the steering of a lateral well being drilled below the target formation.