Advanced petroleum engineering
Homework #04 for Chapter 4 PROPERTIES OF RESERVOIR FLUIDS
1. Calculate the gas deviation factor of a natural gas sample under reservoir pressure
and temperature of 2,000 psia and 130°F, respectively. The composition of the
natural gas, as measured in the laboratory, is the following: methane, 90%; ethane,
7.5%; propane, 1.5%; and n-Butane, 1%.
Component
Mole Frac.
Mol. Wt.
Pc
Tc
Methane
0.9
16.043
666.4
343.33
Ethane
0.075
30.070
706.5
549.92
Propane
0.015
44.097
616.4
666.06
n-Butane
0.01
58.123
527.9
734.46
2. Using the natural gas sample in Ex.1:
(a) Calculate the specific gravity of the natural gas sample under atmospheric
conditions.
(b) Calculate the density of the same gas both at standard and reservoir
conditions. Assume standard conditions to be 14.69 psia and 60°F.
3. Recompute the gas deviation factor of the natural gas sample based on the specific
gravity calculated in Ex.2, and compare it with the result obtained in Ex.1.
4. Calculate the viscosity and compressibility of the gas mixture described in Ex. 1 at
reservoir conditions.
5. Calculate the formation volume factor and expansion factor of the natural gas
sample in Ex.1.
Note: the equations of calculation for Ex.1~Ex.5 should be firstly introduced
when you are doing your operations.
6. Describe the general classification of petroleum reservoirs (up to 6 categories).
What factors determine the type reservoir? Name one large field from each
category, along with its location and reservoir, by conducting a literature review.
7. Describe the processes related to constant composition expansion (CCE),
differential vaporization, and constant volume depletion (CVD). Tabulate the
parameters that can be obtained from each test, with briefly comments explaining
how the results are utilized in reservoir studies.