American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.


Formation evaluation of clastic formations in Cased Hole uses the principals and logics of Sandstone II and Complex Reservoir Formation Analysis. Included in the Program are analysis from Open Hole Surveys, when available, along with analysis of the Carbon Oxygen Ratios, Silicon Calcium Ratios, Gamma Ray, Silicon, Calcium, Compensated Neutron, Neutron Lifetime Sigmas, near detector curve from the Lifetime Log, and for detector curve from the Lifetime Log measurements. The Cased Hole Clastic Evaluation will allow analysis of possible hydrocarbon bearing zones regardless of water salinities through casing.

Matrix constants, formation salinities, clay volumes, formation fluid parameters, i.e., water, gas, and oil, are determined from comparison of a series of checks and balances of the survey responses and their material balance equations. The analysis is presented in analog form along with a printed report and commentary. Examples are shown from the Gulf Coast, California, Red Desert, and East Texas of the analysis along with tested results.


Evaluation of clastic formations in cased holes uses pattern recognition in (addition to the principals and logic of Dresser Atlas' evaluation programs for Sandstone and Complex Reservoir formations. The evaluation technique allows analysis through casing on possible hydrocarbon bearing zones regardless possible hydrocarbon bearing zones regardless of water salinities. Data are utilized from Gamma Ray Logs, Silicon/Calicum (Si/Ca) ratios, Silicon/Calcium (Si/Ca) continuous curves, Carbon/Oxygen (C/O) ratios, Inelastic Neutron Logs, Compensated Neutron Logs, Dual Detector Neutron Lifetime Logs and open hole surveys.

Matrix constants and formation salinities are determined from crossplots. Shale volume parameters are calculated. Then the data is parameters are calculated. Then the data is compared in a series of checks and balances using crossplots of porosities that are shale volume corrected.

Data output is in analog and tabulated form. The analog plot is the Cased Hole Exploration Service Epilog, (Figure 8C). Displayed on a four track grid, the curves are recorded as follows:

Track I Lithologic characteristics - Shale% of Bulk Volume, Permeability Index, and C/O Ratio measurements.

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