Petroleum Engineering 324 Well Performance Daily Summary Sheet Spring 2009 Blasingame/Ilk. Date: Materials Covered in Class Today: Comment(s):

Petroleum Engineering 324 Well Performance Daily Summary Sheet Spring 2009 Blasingame/Ilk Date: Materials Covered in Class Today: Comment(s):

Petroleum Engineering 324 (2009) Reservoir Performance Objective Estimate oil, gas, and water properties pertinent for well test or production data analysis using industry accepted correlations and/or laboratory data. Thomas A. Blasingame, Ph.D., P.E. Dilhan Ilk Department of Petroleum Engineering Department of Petroleum Engineering Texas A&M University Texas A&M University College Station, TX 77843-36 (USA) College Station, TX 77843-36 (USA) +.979.845.2292 +.979.458.499 t-blasingame@tamu.edu dilhan@tamu.edu Lecture 0 Objectives of Well Tests Slide 8/44

Notes: Lecture 0 Objectives of Well Tests Slide 9/44

PVT: Classification of Reservoir Fluids From: Schlumberger: Fundamentals of Formation Testing (March 2006). Overview: Classification of Reservoir Fluids Generic guidelines on properties of reservoir fluids. Useful to assess dominant component(s) and properties. For PTA, generally assume that a system is dry gas or non-volatile oil. Lecture 0 Objectives of Well Tests Slide 20/44

PVT: Formation Volume Factor Formation Volume Factor: B o,g,w B o,g,w = Fluid volume at reservoir conditions Fluid volume at standard conditions B o,g,w is defined as a volume conversion for oil, gas, or water and is defined on a mass (or density) basis. The Formation Volume Factor "converts" surface volumes to downhole conditions. Typical values: Oil:.2 to 2.4 RB/STB Gas: 0.003 to 0.0 rcf/scf Water:.00 to.03 RB/STB Lecture 0 Objectives of Well Tests Slide 2/44

PVT: Fluid Viscosity Viscosity: μ o,g,w Is a measure of a fluid's internal resistance to flow... the proportionality of shear rate to shear stress, a sort of internal friction. Fluid viscosity depends on pressure, temperature, and fluid composition. Typical values: Oil: 0.2 to 30 cp Gas: 0.0 to 0.05 cp Water: 0.5 to.05 cp Lecture 0 Objectives of Well Tests Slide 22/44

PVT: Fluid and Formation Compressibility Fluid Compressibility: c o,g,w c B db dp o o = + o B B g o dr dp so c g = B g db dp g c B db dp w w = + w B B g w dr dp sw Typical values: Oil: 5 to 20 x0-6 psi - (p>p b ) 30 to 200 x0-6 psi - (p<p b ) Gas: 50 to 000x0-6 psi - Water: 3 to 5 x0-6 psi - Formation Compressibility: c f dφ = φ dp Typical values: Normal: 2 to 0 x0-6 psi - Abnormal: 0 to 00 x0-6 psi - c f Lecture 0 Objectives of Well Tests Slide 23/44

PVT: Various "Black Oil" Fluid Properties "Black Oil" PVT Properties: (general behavior, p b =5000 psia) Note the dramatic influence in properties at the bubblepoint pressure. The oil compressibility is the most affected variable (keep this in mind). Lecture 0 Objectives of Well Tests Slide 24/44

PVT: /(μ o B o ) for p<p b ("Solution Gas-Drive" Case) "Solution-Gas Drive" PVT Properties: (/(μ o B o ), p<p b, p b =5000 psia) Attempt to illustrate that /(μ o B o ) constant for p<p b. This would allow us to approximate behavior using "liquid" equations. This concept is not used extensively in PTA, but sometimes for IPR. Lecture 0 Objectives of Well Tests Slide 25/44

PVT: z vs. p pr and ρ pr (dry gas case) a. "Standing-Katz" base plot (z vs. p pr ) Poettmann-Carpenter Data (5960 data points). b."standing-katz" plot (z vs. ρ pr ) Poettmann-Carpenter Data (5960 data points). Lecture 0 Objectives of Well Tests Slide 26/44

PVT: μ g vs. T (and p) (dry gas case) a. Gas viscosity versus temperature for the Gonzalez et al data (natural gas sample 3) compared to the implicit correlation for gas viscosity (Londono) and the original Lee, et al. correlation for hydrocarbon gas viscosity. b. Original Lee, et al. correlation for hydrocarbon gas viscosity. c. Londono "implicit" correlation for hydrocarbon gas viscosity (residual viscosity type model). Lecture 0 Objectives of Well Tests From: Londono, F.E.: "Simplified Correlations for Hydrocarbon Gas Viscosity and Gas Density: Validation and Correlation of Behavior Using a Large-Scale Database," M.S. Thesis, Texas A&M University (December 200). Slide 27/44

PVT: μ g z vs. p (dry gas case) "Dry Gas" PVT Properties: (μ g z vs. p) Basis for the "pressure-squared" approximation (i.e., use of p 2 variable). Concept: (μ g z) = constant, valid only for p<2000 psia. Also a "warning" NOT to use p 2 basis for p>2000 psia. Lecture 0 Objectives of Well Tests Slide 28/44

PVT: μ g c g vs. p (dry gas case) "Dry Gas" PVT Properties: (μ g c g vs. p) Concept: If μ g c g constant, pseudotime NOT required. μ g c g appears to be power-law with pressure (i.e., μ g c g ap - ). Readily observe that μ g c g is NEVER constant, pseudotime required. Lecture 0 Objectives of Well Tests Slide 29/44

PVT: Questions to Consider Q. Limitations of assuming a "black oil" for liquids? A. There are issues but historically, the use of the constant compressibility concept (i.e., a "black oil") has tolerated even extreme violations of the assumption with few substantial problems. The most obvious case where a black oil concept will not suffice is that of a volatile oil (very high GOR). Q2. Limitations of assuming a "dry gas" for gases? A2. The major limitation is that of very rich gas condensate cases (analogous to the "volatile oil" case mentioned above). Q3. Are existing fluid properties correlations sufficient? A3. For most cases, yes. For cases of extremely high pressure and/or temperature, new correlations are warranted. Lecture 0 Objectives of Well Tests Slide 30/44

One staple here. Name: Section: Date: Petroleum Engineering 324 Well Performance Exercise Problem 03 Introductory Skills Assigned: 30 January 2009 Due: 02 February 2009 [to be submitted in class] 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." (Page of 2) 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." (Print your name) (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 one s 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." Zero Tolerance Policy: You MUST submit this assignment in class ONLY.

Name: Section: Date: Petroleum Engineering 324 Well Performance Exercise Problem 03 Introductory Skills Assigned: 30 January 2009 Due: 02 February 2009 [to be submitted in class]. Natural Logarithm Function: (ln()=0, ln[exp(x)]=x, ln( )= ) Integral Definition: Derivative Definition Evaluate: x ln( x) = dx d [ x ] b ln( ) = I = dx x dx x a x (Page 2 of 2) b Ans. I = dx = (Show all work) a x 2. Exponential Function: (exp(0)=, exp()=2.7828 82284..., exp( )=, exp(- )=0) Integral Definition: Derivative Definition Evaluate: d x exp( ax ) dx = exp( ax) + C [ exp( ax) ] = a exp( ax) exp( ) =? a dx ax dx 0 x Ans. exp( ax) dx = (Show all work) 0 Zero Tolerance Policy: You MUST submit this assignment in class ONLY.

Name: Section: Date: Petroleum Engineering 324 Well Performance Exercise Problem 03 Introductory Skills Assigned: 30 January 2009 Due: 02 February 2009 [to be submitted in class]. Natural Logarithm Function: (ln()=0, ln[exp(x)]=x, ln( )= ) Integral Definition: Derivative Definition Evaluate: x ln( x) = dx d [ x ] b ln( ) = I = dx x dx x a x (Page 2 of 2) Use integral property: Assume: c = b b a f ( x) dx = f ( x) dx a c f ( x) dx c b a f ( x) = / x f ( x) dx f ( x) dx ln(x) = x b a / xdx ; / xdx = ln( b) and / xdx = ln( a From definition: ) b Therefore: / xdx = ln( b) ln( a) a b Ans. I = dx = (Show all work) a x 2. Exponential Function: (exp(0)=, exp()=2.7828 82284..., exp( )=, exp(- )=0) Integral Definition: Derivative Definition Evaluate: d x exp( ax ) dx = exp( ax) + C [ exp( ax) ] = a exp( ax) exp( ) =? a dx ax dx 0 x x exp( ax) dx = exp( ax) 0 a 0 = [ exp( ax)] a = [exp( ax) exp( a(0))] a x Ans. exp( ax) dx = (Show all work) 0 Zero Tolerance Policy: You MUST submit this assignment in class ONLY.