Name: _____________________________

Petroleum Engineering 324 Well Performance Reading Task No. 1

Spring 2007 Due: 05 February 2007

Handout Paper: "Application of the Back-Pressure Method for Determining Absolute Open Flows of

Large Gas Wells" by M.A. Schellhardt (1944) 1. Explain the motivation of the author for writing this report. 2. How did Rawlins and Schellhardt obtain the relationship to determine the deliverability of the gas wells?

Explain if this relationship is applicable to oil wells (or not). 3. List the primary factors for the sources of error in calculated (bottomhole) pressures. Explain how these

factors affect back-pressure calculations. 4. In the deliverability equation, state the definition of the "n" parameter? How is this parameter deter-

mined? Explain any physical conditions that the n-parameter represents. 5. State (and explain) the procedure for obtaining the absolute open flow using the back-pressure data. Lecture Material: Objectives of Well Test Analysis Introduction to Porosity and Permeability Concepts Properties of Reservoir Fluids

1. Explain the apparent relationship between porosity and permeability. Discuss if there is/are any univer-sal concept/correlation(s) that can be used to describe porosity-permeability relations. List the factors which affect permeability.

2. Discuss the importance/relevance of "petrophysics" in terms of well performance. 3. Sketch the P-T diagrams for each reservoir fluids (black oil, volatile oil, wet gas, retrograde gas and dry

gas) include the "typical" pressure path of depletion for each reservoir fluid. Explain the roles that phase behavior (or PVT) concepts play in well performance?

4. Describe the PVT properties for the types of reservoir fluids: (sketch each as a function of pressure) Black-oil: (p/pb > 0) Bo, Rso, u, co Solution gas drive: (p/pb < 0) Bo, Rso, u, co Dry gas: z, g, cg

5. What are the objectives of well test/production data analysis? _____________________________________________________________________________________ Required:

You are to prepare a typed report for this reading task addressing all points in each subtask as assigned. Plots or sketches can be made by hand, and can be inserted into the report where appropriate. Failure to address all tasks will result in penalties.

This page and the "Honor Code" coversheet are required as coversheets to your report for this read task. _____________________________________________________________________________________

Petroleum Engineering 324 Well Performance Reading Task No. 1

Spring 2007 Due: 05 February 2007

Assignment Coversheet

(This sheet must be included with your work submission)

Required Academic Integrity Statement: (Texas A&M University Policy Statement)

Academic Integrity Statement

All syllabi shall contain a section that states the Aggie Honor Code and refers the student to the Honor Council Rules and Procedures on the web.

Aggie Honor Code "An Aggie does not lie, cheat, or steal or tolerate those who do."

Upon accepting admission to Texas A&M University, a student immediately assumes a commitment to uphold the Honor Code, to accept responsibility for learning and to follow the philosophy and rules of the Honor System. Students will be required to state their commitment on examinations, research papers, and other academic work. Ignorance of the rules does not exclude any member of the Texas A&M University community from the requirements or the processes of the Honor System. For additional information please visit: www.tamu.edu/aggiehonor/

On all course work, assignments, and examinations at Texas A&M University, the following Honor Pledge shall be preprinted and signed by the student:

"On my honor, as an Aggie, I have neither given nor received unauthorized aid on this academic work."

Aggie Code of Honor:

An Aggie does not lie, cheat, or steal or tolerate those who do.

Required Academic Integrity Statement:

"On my honor, as an Aggie, I have neither given nor received unauthorized aid on this academic work."

_______________________________ your name printed _______________________________ your signature

Coursework Copyright Statement: (Texas A&M University Policy Statement)

The handouts used in this course are copyrighted. By "handouts," this means all materials generated for this class, which include but are not limited to syllabi, quizzes, exams, lab problems, in-class materials, review sheets, and additional problem sets. Because these materials are copyrighted, you do not have the right to copy them, unless you are expressly granted permission.

As commonly defined, plagiarism consists of passing off as ones own the ideas, words, writings, etc., that belong to another. In accordance with this definition, you are committing plagiarism if you copy the work of another person and turn it in as your own, even if you should have the permission of that person. Plagiarism is one of the worst academic sins, for the plagiarist destroys the trust among colleagues without which research cannot be safely communicated.

If you have any questions about plagiarism and/or copying, please consult the latest issue of the Texas A&M University Student Rules, under the section "Scholastic Dishonesty."