Its been almost more than 100 years since first drop of oil was taken out from Earth and we are now more than ever dependent on this Black Gold which has revolutionized human development to present. In layman term’s this Dirty fluid keeps the world moving and one of the most important role is played by oil in getting us to where we are now. Well, Let’s think about the future, not the past. Unlike any other industry most of questions regarding origin distribution and Amount of hydrocarbon present beneath earth remains unanswered. It was long been speculated that we would run out of oil someday but nobody is able to predict exactly when? So, Why are we still not able to answer most of the questions about oil and gas reservoirs?
While Oil & Gas Reservoirs have been producing from last century still doubt remains about accurate science of flow of fluids inside reservoirs. Petroleum Engineering as a science is developed by combining different core science principles and applying them to predict unknown behavior of fluid flow. There has been many great insights done by curious minds to know what actually drives flow of hydrocarbons inside reservoirs which gave rise to science of reservoir engineering which still is in its young stage. According to me we still need some great and curious mind of world to work on this amazing phenomenon of mother nature. However, being complex and unknown the tasks are not as simple as it might seem.
One of the most important functions of the reservoir engineer is to predict the reservoir performance and thus economize recovery of hydrocarbons. Most often this is done with help of reservoir simulation AKA material balance, decline curve. However, most of the time the availability of data is limited, since data collection cost a lot to E&P companies. So many proposed correlations or geostatistical methods are used to upscale the data to the required model. A good reservoir engineer must understand the importance of data and it is his duty to gather all the information that data gives so he/she could realistically determine the reserves and the future performance of reservoir. Types of data gathered are summarized below:
1.) Drill cuttings & measuring while drilling parameters (MWD & LWD).
2.) Subsurface structure from seismic and logging data.
3.)Coring data: Important but expensive operation. Once we have representative cores we can run many experiments to deduce reservoir parameters.
4.)PVT data: Expensive yet necessary for reservoir simulation.
5.) Pressure transient or Rate transient data.
Reservoir engineer is the one who applies Physics, chemistry and maths to reservoir and hence he/she has to understand completely laws governing the fluid flow & rock fluid interactions taking place inside reservoir.