Depth Conversion is well known as a very important step in seismic reflection, and essentially is the process which converts the time acoustic waves take to return to a measurement device – the first step toward accurate assessment of the compound of the many layers of earth beneath our feet – utilised by many well logging and oil and gas exploration companies across the world.
Depth Conversion is a principle which is iterative. While indeed the time between a pitch echoing back toward a receiver may not mean much at all when you think of how to even know what compositions the ground beneath our feet take, it is merely the first step.
The variances in these timings indicate a great number of factors – as a material which is denser than others will reflect back sound in a different manner to something which is more porus. The recordings- or more accurately, the space between reflected sounds- is recorded, and then compared to a vast library of all known depth conversion results, in order to ascertain the characteristics of the ground.
You might wonder what exactly the point is of knowing. The answer is that depth conversion saves time and money in matters of oil discovery and excavation. As you might be able to imagine, boring holes into the earth is not a cheap process, so it imperative to oil and gas companies to have an informed idea regarding the location of these resources.
Furthermore, depth conversion has come on leaps and bounds since its creation. Depth conversion is something which can now give a good indication of many factors, such as the quantity and viability of oil or gas which is discovered – and can even be used in marine applications. While indeed it is not a science that offers total accuracy, depth conversion is still something which offers a good insight.
There are things that can be done in order to increase the accuracy of the depth conversion, too. When a measurement of timing has been taken, a series of formulas and scientific methods are applied in order to turn this time into a depiction of depth. This process is quite long and rather arduous, as a series of solutions must be found in order to become a three dimensional velocity model.
Well Tops have to be identified from the depth of the geological layers which are encountered throughout the oil / gas well, velocity measurements must be applied and considered and empirical knowledge about the rock velocity should be investigated in order to derive RMS stacking velocities in order for a velocity model to truly be considered three dimensional.
Depth Conversion is not an optional process, and finding methods to increase the accuracy and the speed of depth conversions is imperative.
To this end, there are a number of plugins which can be applied to Schlumberger’s Petrel and IHS Kingdom, which allow you to use uncertainty tools which are both capable of producing a far faster result, and a more accurate one as well.
There are many things which are generally true in life. One of which is that haste makes waste, but in the case of depth conversion, Equipoise Software’s Velit plugin for IHS Kingdom and Petrel allows you to make faster uncertainty assessments, using its unique Wizard function.
The Wizard applies a series of algorithms to your data in order to properly interrogate it, at a fraction of the time of which it should take manually. You’ll be able to generate a best-case model from your data, which can be turned into a multi realisation workflow with a simple click of a button.
Depth conversion is a process which is well known for being quite arduous, but with the right tools, you’ll be able to get far more out of your models in a much simpler fashion.