Redeveloping a Permian Basin Waterflood
Authors: Looney Eric M. 
Published: June 2014

There are thousands of small oil fields across west Texas past their prime production periods that have produced millions of barrels of oil, but produce less than a hundred barrels today. These fields have potential but had never been the best investment opportunity and have been continually passed over for more exciting projects. A study over a similar field will be presented in this paper; a project undertaken by undergraduate interns on a field that was low on the team's priority list but still had potential to add reserves.

The lease being redeveloped is primarily an oil lease that has produced over eleven million barrels of oil equivalent over the past forty-five years, but has not seen any development for over a decade. The principal objectives were to update the geological maps and correlations, determine the bypassed hydrocarbon potential, and create a plan to accelerate reserve recovery.

Introduction

As the price of oil continues to rise, the risk to reward ratio for redeveloping old oil fields keeps improving. Increased attention is being paid to fifty year-old fields in order to maximize profits with prices at all time highs. Because old fields are studied and redeveloped instead of simply maintained, the engineer's work load continues to swell. Important, value adding projects are increasingly being assigned to undergraduate engineering interns. An example of such a project will be given in this paper.

The field was discovered in the mid-1960s, and is geographically located in the Permian Basin region of Texas, west of Midland. A majority of the field was originally developed with a shared water injection project between the two primary operators. A total of 30.1 MMBOE has been produced.

The specific lease studied accounted for over a third of field production. It is one of only a couple large, productive leases in the field. Operators have been interested in doing work on the lease since the early 1990s as evidenced by the independent field studies commissioned, the most recent being in the early 2000s. However, no wells were drilled and no significant work other than routine maintenance was done in the last decade.

During the summer of 2007 a geology intern and I were given the responsibility of studying this lease and creating a plan for future development.

Project Objectives

The lease history was not initially clear; therefore, it was necessary to analyze field performance and review past methods of maximizing recovery. This was time intensive and involved data mining to make certain that the lease production and workover history was accurate in the database. Geology re-correlated all logs to update flow units in the field. The initial hypothesis was that the inherited map's flow units were not lined up properly based on the inability to reconcile water injection and production data. The logs were reviewed so flow units and mapping could be updated and volumetrics recalculated. The key to the project was identifying bypassed reserves and how to produce them. It was determined that there is an economically feasible amount of hydrocarbons remaining; therefore, a development plan was created.