Monday, May 20, 2019

Gaseous Equivalent: 2018 #14

Problem 14. A 50 API retrograde gas-condensate reservoir at 2,500 psia & 225 dF has a gaseous equivalent (scf) closest to: (A) 720 (B) 770 (C) 820 (D) 870?

Straightforward 3-step solution; 13 RES 11 has all needed equations on a single page:
1. Mo = 5954/(api-8.8) = 145.
2. SGo=(1.008*145)/(42.43 + 145) = 0.78.
3. 133,300(0.78/145) = 719 or (A).

Note this problem is more wordy and confusing than is shown above; for the answer here I merely remove all the unneeded information for clarity. But I strongly recommend doing these practice problems in test format. Practicing the confusing nature of problem wording, under time constraint, is critical.

Friday, May 17, 2019

Cement Mix: 2018 #13

Problem 13. ...mix...sack of Class A cement slurry...4% bentonite...standard water...weight of the slurry (pounds): (A) 161; (B) 159; (C) 157; (D) 155.

Slurry volume & density calculations for this exact situation are on 5 CMT 2. Note there are 4 components: cement, cement water, additive, and additive water. They combine for 11.34 gal/sk & 14.18 lbm/gal as shown on the page. Multiply them for 161 lbm/sk (A).