List of top Petroleum Engineering Questions asked in GATE Petroleum Engineering

A compressional acoustic wave takes $55~\mu s$ to travel $0.3048~\text{m}$ through a rock formation having bulk modulus of $37.5~\text{GPa}$ and shear modulus of $31~\text{GPa}$. The bulk density of the rock is ............. kg/m$^{3}$ (rounded to two decimal places).

After well completion, a discovery well in an oil reservoir is produced for a short period and then closed for pressure build-up test. The production history before shut-in is given below. The Horner’s pseudo-producing time, $t_{pH}$, is ............... hr (rounded to nearest integer). 

Production rate (STB/day)Duration (days)
5005
5507
4008

 

Consider 1D oil--water flow with $k_{ro}^o=1,\ k_{rw}^o=0.2,\ S_{wr}=0.2,\ S_{or}=0.4$. Oil and water viscosities are $5$ cP and $1$ cP. With \[ k_{ro}=k_{ro}^o(1-S_w^*),\quad k_{rw}=k_{rw}^o(S_w^*),\quad S_w^*=\frac{S_w-S_{wr}}{1-S_{or}-S_{wr}}, \] the total relative mobility at $S_w=0.4$ is _________ cP$^{-1}$ (rounded to one decimal place).

A build-up test is characterized by production at constant rate over time $t_p$, followed by shut-in period of $\Delta t$. A plot of shut-in bottom hole pressure ($P_{ws}$) with $\log \left(\dfrac{t_p+\Delta t}{\Delta t}\right)$ for pressure build-up test data is shown in the figure. Which of the following statement(s) is/are TRUE?

Match the entries between Group-I and Group-II for seismic data acquisition, processing and interpretation.

Schematic of phase diagrams for a pure gas hydrate system of methane (CH$_4$), carbon dioxide (CO$_2$), hydrogen sulphide (H$_2$S) and nitrogen (N$_2$) between the lower and upper quadruple points are shown in the figure. Arrowheads indicate the stable hydrate region for a particular gas hydrate system. Match the phase diagram with the corresponding pure gas hydrate.

The figure shows a schematic representation of the organic solid phase diagram for wax, hydrate, and asphaltene deposition around the bubble point of a sample reservoir fluid. Arrowheads indicate the stable region for a corresponding organic solid. Match the phase diagram with organic solids. 

Match the flow regimes associated with a vertically fractured well in a reservoir. 

Consider the following accident scenario: Failure of a drain connection on a rich oil line at the base of an absorber tower in a gas producing plant allowed the release of rich oil and gas. The resulting vapor cloud ignited from the ignition system of an engine-driven recompressor. The absorber tower eventually collapsed across a pipe rack. The breakage of the pipelines added more fuel to the fire and led to the total destruction of the plant. The resulting fire burnt for 3 days. 

The mean free path of the gas molecule is $10^{-6}$ mm, while the pore size of the rock is $10^{-3}$ mm. Which of the following statements is TRUE?

Contact angle measurements are often performed on smooth surfaces to gain information about the wettability of a surface. The interfacial tensions between solid-liquid, liquid-air, and air-solid are $\gamma_{SL}$, $\gamma_{LA}$, and $\gamma_{AS}$, respectively. Which of the following expressions describes the contact angle, $\Theta$? 

A first arrival amplitude of the Cement Bond Log (CBL) of a cased hole section is given in the figure. The identified depth intervals P, Q, and R represent

The response of a four-arm caliper (dual caliper) log in a drilled section is shown in the figure. The borehole features associated with the three identified sections P, Q, and R are:

Kerogen is an intermediate compound in the process of petroleum formation in a sedimentary basin. This is typically classified into four categories (Type-I, Type-II, Type-III and Type-IV) based on the relative amount of carbon (C), hydrogen (H), oxygen (O) present in it (shown in the figure below). Which of the following is the X-axis and Y-axis, respectively?

Consider an ideal liquid–vapor mixture at equilibrium having liquid phase mole fraction $(x_i)$ and gas phase mole fraction $(y_i)$ of component $i$. If at a given temperature, $P_{v_i}$ is the vapor pressure of pure component $i$ and $P$ is the total pressure, then the equilibrium ratio $(k_i)$ is

An opaque cylinder (shown below) is suspended in the path of a parallel beam of light, such that its shadow is cast on a screen oriented perpendicular to the direction of the light beam. The cylinder can be reoriented in any direction within the light beam. Under these conditions, which one of the shadows P, Q, R, and S is NOT possible?

Which one of the given figures P, Q, R, and S represents the graph of the following function? \[ f(x) = |x + 2| - |x - 1| \]

The resistivity reading of a flushed zone across a permeable formation (drilled with water-based mud) is 20 $\Omega\!\cdot$m. Laboratory analysis shows that the resistivity of the core plug (100% saturated with a NaCl brine) from the same formation is 6 $\Omega\!\cdot$m. The resistivity of the NaCl brine is 0.6 $\Omega\!\cdot$m. If the resistivity of the mud filtrate is 0.9 $\Omega\!\cdot$m and Archie's saturation exponent is 2, then the estimated residual hydrocarbon saturation (in percentage) in the flushed zone is ............. (rounded to two decimal places).
A gamma ray log run across a sand–shale sequence recorded maximum and minimum values of $70$ API and $30$ API, respectively. A bed in this sequence has a gamma log value of $50$ API. Assuming a linear relationship between shale index and shale volume, the volume fraction of shale in the bed is ............. (rounded to one decimal place).
A switch-over event in a producing well occasionally results in a reportable oil leak. An analysis of the data shows that the chance of a reportable leak is 1 in 500 switch-over events. It is observed that 10 switch-over events occur every day. If the occurrence of a reportable leak follows a Poisson distribution, the number of days in a year (of 365 days) with no reportable oil leaks from switch-over events is ............. (rounded to nearest integer).
A binary mixture of n-butane (\(C_4H_{10}\)) and n-pentane (\(C_5H_{12}\)) is under thermodynamic equilibrium at 180°F and 95 psia. The vapor pressures of pure C4H10 and pure C5H12 at 180°F are 160 psia and 54 psia, respectively. Assuming ideal solution behavior (i.e., Raoult's law and Dalton’s law are valid), the mole fraction of the n-butane in the gas phase is ............. (rounded to three decimal places).
A highly permeable reservoir with initial reservoir pressure of 3000 psi is under active water drive from a surrounding large aquifer. The final stabilized reservoir pressure is 2500 psi. Following data associated with the reservoir at 2500 psi are given.
Oil production rate = 30,000 STB/day
Water production rate = 0 STB/day
Oil formation volume factor, \(B_o = 1.5 \, \text{bbl/STB}\)
Gas formation volume factor, \(B_g = 0.00070 \, \text{bbl/scf}\)
Water formation volume factor, \(B_w = 1 \, \text{bbl/STB}\)
Producing Gas to Oil Ratio, GOR = 850 scf/STB
Gas solubility, \(R_s = 700 \, \text{scf/STB}\) If the reservoir pressure and the reservoir production rates remain constant, the water influx rate is ............. bbl/day (rounded to nearest integer).
A volumetric undersaturated solution gas drive reservoir (without gas cap, no water influx, and with no initial gas saturation) has an initial water saturation of $15%$ which remains unchanged during production. After the production of $10%$ of the initial oil (measured at surface conditions), the oil formation volume factor $B_o$ is reduced from its initial value of $1.4~\text{bbl/STB$ to $1.2~\text{bbl/STB}$. The final gas saturation in percentage is _________ (rounded to one decimal place).}
Select the statement(s) that is/are TRUE.
A centrifugal pump running at 500 rpm delivers 60 liters/minute with a head of 50 m. At the same efficiency, if the rotational speed is increased to 1000 rpm, the discharge rate and head would respectively be: