A comparison of reservoir gas energy and composition with respect to initial oil production in the San Andres Formation of Shafter Lake Field, Andrews County, Texas

Author

Jacob Ross Smith

ORCID Identifier(s)

0000-0003-4227-0714

Graduation Semester and Year

2018

Language

English

Document Type

Thesis

Degree Name

Master of Science in Earth and Environmental Science

Department

Earth and Environmental Sciences

First Advisor

John Wickham

Second Advisor

Merlynd K Nestell

Abstract

The oil-rich, Permian-age San Andres Formation in the Permian Basin of West Texas produces Wolfcampian-age oil from the dolomitic host rock in prolific amounts. The present study focuses on the Shafter Lake field and utilizes gas analysis reports, well parameters, and 24-hour initial production (IP) reports of oil and associated petroleum gases (preferential to methane) to determine if a correlation exists between formation gas and oil production in the San Andres formation. The San Andres formation undergoes a substantial de-watering process before peak oil-production commences, and this study briefly touches on that subject to account for the massive initial water production which far exceeds the IP of oil. Since the horizontal wells have a first and last perforated zone differential of, on average, twenty-eight times the directional wells, the data is normalized by dividing the production by linear feet of perforated zones. With well type accounted for, normalized IP of oil cross-plotted against normalized IP of gas shows a correlation coefficient of 0.906, which is just over a 90% relation between the oil produced and formation gas produced with it. This relationship can be inferred as either higher oil mobility caused by either gas-cut saturation, or an expanding gas-cap drive upon de-pressuring of the reservoir as a result of extensive production.

Keywords

Oil, San Andres Formation, Gas

Disciplines

Earth Sciences | Physical Sciences and Mathematics

License

This work is licensed under a Creative Commons Attribution-NonCommercial-Share Alike 4.0 International License.

Comments

Degree granted by The University of Texas at Arlington

Recommended Citation

Smith, Jacob Ross, "A comparison of reservoir gas energy and composition with respect to initial oil production in the San Andres Formation of Shafter Lake Field, Andrews County, Texas" (2018). Earth & Environmental Sciences Theses. 164.
https://mavmatrix.uta.edu/ees_theses/164