In this month’s article, Dennis Cooke and John Cant discuss seismic inversion and its limitations, with specific reference to the creation of a single deterministic model, or the evaluation of many probabilistic models to properly predict the presence of hydrocarbons as part of reservoir characterisation.
A deterministic inversion will output one earth property model, whereas stochastic inversion uses an alternate process of searching through many different input models but refines none of them. These input models are usually built using a distribution of earth models generated from your well data. The next step is to output the average of all the ‘Good fit’ models and compare each of them with a synthetic trace which should reflect the true earth impedance.
The benefit of evaluating a deterministic model-based inversion is that you are looking at the output just one earth impedance model that ‘fits’ the seismic data being inverted. Whereas the benefit of stochastic modelling is that you are comparing hundreds of equally probable simulations to gain a ‘highly probable best-fit’ to the data, but you have a risk of being proven wrong by the drill bit.
Kingdom Seismic Inversion uses the Simulated Annealing algorithm to come to a single deterministic model by determining the global minimum value of the solution space, with respect to the true earth impedance values. Working on the 80 : 20 rule, our software has been designed to provide you with a highly competent answer very quickly and should work in tandem with higher grade inversion packages 20% of the time. Using our software in your workflow aims to save you time and money through improving your operational efficiency and will reduce downtime associated with iteratively creating a highly detailed Pre-Stack inversion model, as you will already have answers calculated to work on from.
We hope you enjoy reading about the whole range of different inversion methods discussed in the article. If you’re a seasoned geophysicist and you have time to write an article in the fields of depth conversion or seismic inversion to help the wider geoscience community, then please get in touch here.