Monday, April 26, 2010

Cross checking of quality quantity of petroleum crude oil exploration how to verify?

Your question is not clear. Please specify. I suppose you are speaking about well testing but not sure. In absence of precision, I will give you a general workflow on the method for assessing the quality and quantity of oil in the rock.





Before drilling a well, a seismic is generally shot. It means that vibrations (through air guns in water or truck shaking on land) will be generated, the sound will propagate in the ground and will reflect at the interface of the various rock layers. It will give an idea whether there is trap to keep the oil and how big are these traps. Advanced analysis can even give some clues on the type of fluids in these traps (water, gas or oil). So we get the POSSIBLE/PROBABLE RESERVES.





When a well is drilled, there is inside the drilling assembly of most well a certain set of tools called MWD or LWD (Measurement While Drilling and Logging While Drilling which is one step further). The MWD/LWD is measuring downhole some parameters such as the well inclination and direction toward north, the resistivity of the rock, the natural radioactivity of the rock, the vibration and mechanical parameters (weight, torque etc...). The LWD can also give information on the porosity, the type of hydrocarbons etc... So we get the THICKNESS OF THE RESERVOIR ROCK, THE THICKNESS OF THE OIL/GAS ZONE AND THE POSSIBLE TYPE OF FLUID (OIL/GAS)





Once the well is drilled, the company will 'logged' the well with a set of tools which will give as well all parameters recorded with MWD/LWD plus some extras like permeability, hydrocarbon density etc... Samples can be taken as well and the time for taking a sample at a given pressure will give an idea on the permeability of the rock. The fluid taken downhole are brought and later are carried detailled analysis, called PVT and petrochemical analysis (for Pressure/Volume/Temperature). So we get the ACCURATE THICKNESS OF THE RESERVOIR AND THE HYDROCARBON ZONE, THE TYPE OF HYDROCARBONS DOWNHOLE, THE POSSIBLE PRODUCTION LEVEL OF THE WELL.





However, people in the oil company really like it big and practical, so they are carrying well test. Basically, they will allow the well to produce the oil or the gas, measure with various settings the amount of oil and gas produced and the quality of the oil, mainly the density and for the gas the various gas components (Methane, Ethane, Propane, Butane and iso-Butane, Pentane and iso pentane). The fluids produced by the well passes through a separator, separating oil from water and from gas and sand. Then the flow(quantity) is measured using various type of flowmeters. Now it is even possible to measure flow without separators by using multiphase flowmeters allowing the calculation of the relative flow of oil, gas and water. So we get the TYPE OF FLUID REALLY PRODUCED AT SURFACE AND THE AMOUNT IT IS POSSIBLE TO PRODUCE IN SAFE CONDITIONS.





I hope this answer your question.Cross checking of quality quantity of petroleum crude oil exploration how to verify?
distill the volatiles, analyze the residues or ash.





Don't really understand the question. Is this at the well, traces in soils and mud, or ?

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