The Uses and Limitations of Computers in Petroleum Engineering Work
Authors: Ferguson D.S. , Attra H.D. 
Published: December 2007

Computer usage in the oil industry has progressed to the point where every engineer should be familiar with calculation procedures that can be applied to his work. This knowledge will allow him to evaluate the procedures published in the literature and determine the advantages and disadvantages of using a computer to do a certain job. In petroleum engineering work computers have been used to solve problems in:surface separation;primary reservoir performance;pressure maintenance and secondary recovery operations;gas-field operations including retrograde behavior, cycling, deliverability, gas plant operations, gas pipeline operations and compressor requirements;economics;maximizing profits or minimizing costs;statistical analysis; andgeneral engineering practices such as drilling, casing design, compressor design and log interpretation.

There are advantages and disadvantages in the use of a computer for performing the calculation work that may be required in solving specific problems, and certain of the calculation procedures are not available without the aid of a computer. Because its petroleum engineers may be scattered over a large operating territory, a company can greatly enhance the efficient use of its computing facilities by a well planned organizational set-up. These computing facilities may be company-operated, company rented or handled by a consultant. The important thing is that the engineer be given free access to the use of the computer, either directly or through close coordination with a computing group comprised of engineers with backgrounds similar to his own who are trained in the use of computing equipment.

Introduction

Developments in computing equipment and procedures during recent years have caused some marked changes in basic engineering responsibility. The development has occurred at a rapid pace, and the oil industry has been quick to take advantage of these new tools. Today it has become apparent that every engineer should know something about the application of computing machines for solving problems in his field. There certainly are many valid reasons for not employing a computer to do certain jobs, and it definitely is true that a company can become over-expended with expensive equipment and an inefficient computing organization. The purpose of this paper is to discuss the efficient use of computers in petroleum engineering work. This discussion will includethe uses and limitations of a computer for solving various classes of petroleum engineering calculations anda summary of the basic requirements of an efficient engineering computing organization.

For the purpose of discussion, the various calculation procedures have been grouped into the following categories:phase-behavior flash calculations,reservoir performance calculations not requiring phase-behavior considerations,reservoir performance calculations requiring phase-behavior considerations,two-dimensional reservoir studies,gas-well deliverability studies,economic analyses,optimization studies,statistical studies andgeneral engineering analyses.

In a large engineering organization, various engineers in different locations will spend a great deal of time in simply equipping themselves with the correct equations, factors and experience necessary to perform certain calculations for the first time. A computer program, once prepared with a correct set of equations and factors, leaves all of the time open for gaining experience. There is no substitute for engineering experience in analyzing a problem and deciding whether or not detailed calculations are warranted. Along this line, it is essential for effective computer utilization that the validity of the basic data and the end use of the answer justifies the expense of a better study than can be obtained by an intuitive analysis or a good engineering estimate. This point cannot be overemphasized and should be kept in mind during the discussion of the various calculation procedures.

Phase-Behavior Flash Calculations

The flash calculation is an extremely useful engineering tool for which there is no complete substitute or short-cut.

JPT

P. 625^