Robert C. Ransom

What are Archie’s Basic Relationships

What is Meant by the Plot of *R*_{t} versus *S*_{wt}*ϕ*_{t}

Parallel Resistivity Equations Used in Resistivity Interpretation

What is the Formation Resistivity Factor

How is Exponent *n* Related to Exponent *m*

Observations and Conclusions from Figure 10 about Exponent *n*

Are There Limitations to Archie's Relationships Developed in this Model?

**Table of Retrievable Contents:**

**ARE THERE LIMITATIONS TO ARCHIE'S RELATIONSHIPS DEVELOPED IN THIS MODEL?**

Are there rocks that complicate resistivity interpretations? Of course. As in every discipline and in every analytical method, there can be problems that complicate the interpretation process. That is not unique to Archie’s relationships, whether new or old. Above, it was mentioned that Archie’s relationships, as they have been developed in this paper, apply to heterogeneous rocks with uniform distributions of porosity, saturations, and electrically-conductive constituents. That is a requirement for all matter subject to electrical investigations. Problem rocks are those that exhibit nonuniform distributions of causative factors that influence resistivity. Such factors or conditions can be, but are not limited to: anisotropy, beds considerably thinner than the vertical resolution of the logging tools, bedding planes at high angles relative to the borehole axis, human error in running the wrong resistivity-measuring tool for the existing resistivity profile in the mud-filtrate invaded zone, etc. Are these Archie problems? No. These are problems that affect all related analytical methods. These are problems that either nature or the shortcomings of man have dealt to the analyst. These conditions are part of the interpretation process and require the attention of qualified well-log analysts.

**A CLARIFYING CONCEPT OF ARCHIE'S RESISTIVITY RELATIONSHIPS AND PARAMETERS.**

**A MODEL AND DISCUSSION**

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