3. Many problems are extremely difficult (but still fair in that any competent engineer should have a reasonable chance at solving). Examinees often must select multiple answers, and so know the exact answer. Bluntly, guessing is now unreliable.
4. Solutions are given in detail at the end of the text, with exact quotes and specific calculations, as well as the precise SPE and Guidebook source location.
Prior problem sets 2018, 2017, and 2016 were designed for the pre-2019 exam and to learn the Guidebook for the exam. They served this purpose very well. However, now that the exam is closed book, it is critical to use the SPE 2019 Reference Guide when doing problems to learn the equation locations. This problem set is designed to be used in this way.
True statements about drive mechanisms include (select any that apply):
__ Secondary recovery requires “repressurizing” or increasing the reservoir pressure.
__ Oil reservoirs are not classified according to their fluid type.
__ Black oil typically ranges from 70 to 150 in molecular weight.
__ Black oil can have a molecular weight of 210.
__ Oils with molecular weights over 150 are usually classified as heavy oils.
__ Volatile oils exhibit an initial oil FVF in the range of 1.5 to 3.0.
__ Black oils exhibit an initial oil FVF in the range of 0.6 to 6.
__ Black oils exhibit an initial oil GOR in the range of 200 to 900 scf/STB.
Keep in mind the the provided Reference Guide will offer no assistance on these types of word problems. There is really no shortcut except to know the material. Translation: study! Most of these word-style questions will come from the SPE Handbook Series (as well as the SPE Textbook Series (TS), especially TS12). So a good study plan is to merely read the parts of the HS you are unfamiliar with. The questions I provide in the 2021 practice problems give a good test of your knowledge.
Click the button for the answer, along with commentary and SPE references sourced. Note that the provided SPE Reference Guide will not help at all on these types of problems. Feel free to ask questions in the comment box below.
X Secondary recovery requires “repressurizing” or increasing the reservoir pressure. (HS5 P895)
__ Oil reservoirs are classified according to their fluid type. (HS5 P895) X Black oil typically ranges from 70 to 150 in molecular weight. (HS5 P896) X Black oil can have a molecular weight of 210. (HS5 P896)
__ Oils with molecular weights over 210 are usually classified as heavy oils. (HS5 P896) X Volatile oils exhibit an initial oil FVF in the range of 1.5 to 3.0. (HS5 P896)
__ Black oils exhibit an initial oil FVF in the range of 1.1 to 1.5. (HS5 P896) X Black oils exhibit an initial oil GOR in the range of 200 to 900 scf/STB. (HS5 P897)
If a 10,000 ft drillstring’s frictional pressure loss is 1,433 psi, and the 12 lbm/gal mud returns fill a 10 ft x 10 ft tank at 6-1/2 inches per minute, the pressure at the base of the drill collar is closest to? The ID of the drill collars is 2.5 in and pump pressure is 3,000 psi.
A) 7825
B) 7819
C) 7813
D) 7800.
This problem is solved using the standard mechanical energy balance equation. Note the only source truly needed to solve it is the SPE Reference (to calculate the pressure from gravity). If you don't include the KE effect will be off just slightly. Note KE is generally ignored in the field but don't dare ignore it on the exam and this problem shows how will get the wrong answer if you do (even though you don't need to know precisely what the KE value it is to get it right, just that it's there).
Sources: SPE Reference, Guidebook 8 FAC 6, TS2 P129.
A true vertical depth well log (all depths ss) shows a structure top at 7,980 ft and an OWC about 8,140 ft. The log also shows three porosity intervals 35 ft, 30 ft, and 30 ft thick, with porosity interval tops at 8,020 ft, 8,070 ft, and 8,100 ft, each separated by shale breaks. A true statement regarding calculating volumetric reserves in the above situation is (select any that apply):
This type of problem tests your knowledge of P2 and P3 reserves, logging data, and general oilfield knowledge. In the end, there is no shortcut to understanding the basics of logging data. So if it's not something you work with often, get familar with the applicable SPE Handbook and SPE Textbook material. The Guidebook has a good summary as well.
Well 34X was drilled and completed, but there is debate about the quality of the wireline logs. During well testing, 34X produced 10,200 SCF of 0.8 specific gravity gas with 20 STB of 30 API oil. If the reservoir has a FVF = 1.4 bbl/STB, the fluid gradient is closest to:
A) 0.28 psi/ft
B) 0.29 psi/ft
C) 0.30 psi/ft
D) 0.31 psi/ft.
This problem can be solved using the new Reference exclusively. A similar problem can be found in the Guidebook 13 RES 9. TS8 P33-35 has some good explanations as well.
Seismic fundamentals should include basic vocabulary. This includes source, receiver, 2D, 3D, structural, stratigraphic, amplitude, phase, frequency, and propagation velocity. Stick to the basics, as it is unlikely to get overly technical, especially on calculation problems. This problem is so-so, difficulty-wise, depending on your experience.
I find flaring, like DCA, tends to trip up the overconfident. This one is tricky; it tests your knowledge of "sour gas" and how combustion works chemically. Plus, it's a unit nightmare.
Sources include the Guidebook 8 FAC 9 (there isn't much else out there that I've found) and this problem can be solved using
the SPE Reference pages 189 and 191 only if you already know what you are doing. A word to the wise: spend time practicing emission-type problems using the new SPE resource, because you will likely need to know where to go quickly and you won't have the Guidebook available to hold your hand on a closed book exam.
True statements about oil and gas separators include (select any that apply):
__ Typically, oil must have less than 1% (by volume) water and gas less than 1 lbm water/MMscf to meet saleable pipeline specifications.
__ Typically, the four stages of depressurization are high pressure (HP), intermediate pressure (IP), free water knockout (FWKO), and the degasser/bulk oil treater (BOT) combination.
__ Bulk water is removed in the FWKO and final dewatering is accomplished in the BOT.
__ Staged separation (depressurization) is required to maximize the liquid hydrocarbon volumes.
__ Water may be removed in the HP and/or IP vessels.
__ The BOT is typically an electrostatic treater.
__ Sometimes the BOT will include a degassing section, eliminating the need for a separate degasser.
__ Typical deepwater platform pressures are 1,500, 700, 250, and 50 psig for the HP, IP, FWKO, and degasser stages, respectively.
__The terms “stage separator “and “trap” refer to a non-conventional oil/gas separator.
__ A flash chamber (trap or vessel) normally refers to a conventional oil/gas separator operated at high pressure, with the liquid from a higher-pressure separator being partially vaporized or “flashed” into it.
__ An expansion vessel is the first-stage separator or a low-temperature or cold-separation unit.
__ A gas scrubber is similar to an oil/gas separator. Usually, it handles fluid that contains less liquid than that produced from oil/gas wells.
__ Gas scrubbers are normally used in compressor trains, gas gathering, sales, and distribution lines, where they are required to handle slugs or heads of liquid.
Click the button for the answer, along with commentary and SPE references sourced. Note that the provided SPE Reference Guide will not help at all on these types of problems. Feel free to ask questions in the comment box below.
__ Typically, oil must have less than 1% (by volume) water and gas less than 5 lbm water/MMscf to meet saleable pipeline specifications. (HS3 P13) X The four stages of depressurization are high pressure (HP), intermediate pressure (IP), free water knockout (FWKO), and the degasser/bulk oil treater (BOT) combination. (HS3 P13) X Bulk water is removed in the third stage, FWKO, and final dewatering is accomplished in the BOT. (HS3 P13) X Staged separation is required to maximize the liquid hydrocarbon volumes. (HS3 P13) X Water may be removed in the HP and/or IP vessels. (HS3 P13) X The BOT is typically an electrostatic treater; sometimes , the BOT will include a degassing section, eliminating the need for a separate degasser vessel. (HS3 P13) X Typical deepwater platform pressures are 1,500, 700, 250, and 50 psig for the HP, IP, FWKO, and degasser stages, respectively. (HS3 P13).
__ The terms “oil/gas separator,” “separator,” “stage separator, “and “trap” refer to a conventional oil/gas separator. (HS3 P14)
__ A flash chamber (trap or vessel) normally refers to a conventional oil/gas separator operated at low pressure, with the liquid from a higher-pressure separator being partially vaporized or “flashed” into it. (HS3 P14) (HS3 P14) X An expansion vessel is the first-stage separator or a low-temperature or cold-separation unit. This vessel may be equipped with a heating coil to melt hydrates, or a hydrate -preventing liquid (such as glycol) may be injected into the well fluid just before expansion into this vessel. (HS3 P14) X Gas scrubbers usually handles fluid that contains less liquid than that produced from oi/gas wells. (HS3 P15)
__ Gas scrubbers are normally used in compressor trains, gas gathering, sales, and distribution lines, where they are not required to handle slugs or heads of liquid. (HS3 P15)
The new SPE Reference Guide has the necessary equations for horizontal separators, including the "effective" and "seam-to-seam" length calculations. However, they are in a different format that many are used to, so spend some time running calcuations using these equations. Comparing the Guidebook's simple format to the Reference can help here. This problem is included in this problem set for this purpose.
