Introduction to Oil Reservoirs and Engineers

Petroleum Engineering is one of the key aspects of engineering that is concern with the exploration and production of hydrocarbons from the subsurface of the Earth. 

A wellbore is a small hole with just a few inches in radius that provides us access to the Earth’s subsurface. 

The oil and gas extracted from these wellbores are consumed in various forms by individual consumers, host countries or globally. 

Petroleum engineering is a broad discipline that has several areas of specializations such as Petroleum Geology, Petrophysics, Drilling, Mud and Cementing, Reservoir, Production (surface & subsurface), Completion, Formation evaluation, Economics, etc. 

Petroleum Engineers from these broad areas of specialization work together in an integrated team to achieve one common goal;  to recover the hydrocarbon in a safe and cost-effective way. alert-success

Reservoir engineering is the study of reservoir and technical aspects related to it. The relevant technical aspects that we want to focus on are, but not limited to, Fluid Mechanics, Thermodynamics, Mathematics, and Geology. Don't worry, I'll be more descriptive in upcoming paragraphs if you do not get it.

Visualization of Reservoir

First let's see what a Reservoir is. In simple words, a reservoir is a part inside the Earth that is capable of storing hydrocarbons. The reservoir is porous enough and it has any kind of seal at the top which does not let them escape from there. The fraction of the reservoir which can store fluid is called porosity.

Visualization of Porosity

A reservoir is a porous medium like a sponge, but is not as soft as a sponge. Usually reservoir rock was once sand and over millions of years, the environment changes. Since it is deep inside the Earth, it carries all the overburden weight above it. Due to this immense amount of weight, the reservoir rock compresses, and porosity decreases with compaction. The same phenomenon applies to the fluids within the subsurface which results in the hydrocarbons rushing out when a well is drilled into the Earth.

Visualization of Permeability

Now we know that hydrocarbons are stored in small pores in the reservoirs, the question we must ask ourselves is “how does it move within the reservoir?” Imagine these small infinite pores connecting randomly, which creates a very thin path. 

These paths allow fluids to move inside the reservoir up to the wellbore. Since the arrangement is random, it might be possible that some part of the reservoir has easy access for fluid and others might have difficulty in moving or it can be trapped also. 

This ability to move fluid in any porous medium is called permeability. It is the measure of the ease with which fluid can flow in a porous medium like a reservoir. 

Now that you know a lot about reservoirs, its physics, and how fluids are stored and moves within the reservoir, let’s take a look into what a Reservoir Engineer does. 

You can’t see it, nor can you touch it, but a Reservoir engineer visualizes what's going on deep inside the earth using the various disciplines mentioned above. 

They have a feel of a reservoirs like their own body part, how they are behaving, and what needs to be done to improve them. That's what makes it interesting. alert-info

Optimization of Oil Production
by understanding reservoir properties 

The primary objective of reservoir engineering is optimization

Optimization of Field - Wells and location

Optimization of Reserves - Extracting as much crude as possible

Optimization of Profit - Maximizing profits for the organization and minimizing environmental impact
    

Engineers must identify and define all individual reservoirs and their physical properties, deduce each reservoir’s performance, prevent drilling of unnecessary wells, initiate operating controls at the proper time, and considering all-important economic factors, including income taxes. 

This is how reservoir engineering is one of the most important aspect of hydrocarbon extraction.

This is a quick introduction to reservoir engineering and engineers. Please let me know If you have any further queries about this, I'll be happy to get in touch.

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