its a reservoir engineering question

Filename: Fluid properties review.doc

PETR 318 RESERVOIR ENGINEERING HOMEWORK 2

Due on Tuesday Jan 26, 2016

Experiments were made on a bottom-hole crude oil sample taken from the North Grieve Field to determine the gas solubility and oil formation volume factor as a function of pressure. The initial reservoir pressure was recorded as 3600 psia and reservoir temperature was 130°F. The following data were obtained from the measurements:

Pressure Rs Bo

psia scf/STB bbl/STB

3600 567 1.310

3200 567 1.317

2800 567 1.325

2500 567 1.333

2400 554 1.310

1800 436 1.263

1200 337 1.210

600 223 1.140

200 143 1.070

At the end of the experiments, the API gravity of the oil was measured as 40°. If the average specific gravity of the solution gas is 0.7.

Answer the following questions: a. What factors affect the solubility of gas in crude oil? b. Plot the solution gas ratio versus pressure. c. Was the reservoir initially saturated or undersaturated? Explain. d. Does the reservoir have an initial gas cap? e. In the region of 200 to 2500 psia, determine the solubility of the gas from your graph in

scf/STB/psi. f. Suppose 1000 scf of gas had accumulated with each stock tank barrel of oil in the reservoir instead

of 567 scf. Estimate how much gas would have been in solution at 3600 psia. Would the reservoir oil then be called saturated or undersaturated?