We consider an oil-well in the Gulf of Mexico the deepest oil rig with a depth of 2450 meters
We consider an oil-well in the Gulf of Mexico the deepest oil rig with a depth of 2450 meters
We consider an oil-well in the Gulf of Mexico, the deepest oil rig with a depth of 2450 meters. The oil is pumped from this depth to a floating spar platform (see image1). In the oil reservoir, the temperature of the oil is around 60˚C. From this reservoir, crude oil is pumped towards the oil-platform. In this assignment, we assume that the pipeline goes straight up to this platform (in reality this is not the case). The oil is pumped via a cylindrical pipeline with an outer diameter of 42 cm and a wall thickness of 1 cm. This platform is said to produce approximately 600 m3/hr oil.
Part I
The goal is to obtain all the information on the flow conditions in this pipeline. Consider steady state conditions.
1a. First try to perform some hand calculations: Assume that ocean water has a constant temperature of 12˚C and that there are no radial temperature differences in the oil stream. You are asked to find a temperature profile (final expression of the oil temperature as a function of the ocean depth, and other parameters). Additional data is given below. Plot the resulting temperature profile as a function of the ocean depth.
1b. One value in the additional data is not correct. From other parameters given in this assignment, the correct value for this wrong parameter can be calculated. Which parameter is this? Calculate the new value and plot the new temperature profile.
2. Derive a pressure profile over the length of the pipeline. The pipe wall may be assumed to be smooth. What should be the pressure after the pump at the bottom of the ocean to pump oil to this platform? Plot the pressure inside the oil pipeline as a function of the ocean depth. The oil should be delivered to the platform at 1 bar.
Additional data:
ρoil= 900 kg/m3
ηoil = 50 mPa.s
λsteel = 14.3 W/(m.K)
λoil = 0.15 W/m.K
hinner = 1000 W/m2.K
Pr = 667 (-)
houter = 100 W/(m2.K)
Cp,oil= 2.0 KJ/(kg.K)
Part II
In reality, the water temperature is not constant, but it varies significantly over the ocean depth (see figure 1). Ocean temperature data is given in the provided matlab file. In this case, a numerical method is required to find a temperature profile over the pipeline. Use the data to approach a realistic temperature profile by using matlab. For this problem, use equations obtained in Part I. Plot the temperature as a function of ocean depth.
Compare temperature profiles of part 1 with part 2 and answer the following questions:
What is a crucial assumption in the pressure drop calculation? Use keyword: viscosity.
What possible measures would you consider to prevent heat loss of oil to the ocean water? How would you see this back in the calculations? Use keyword: Heat resistance
