VelPAK is the name of the product from the Kingdom platform, while the same product is available for velocity modelling in Petrel named Velit.
Gross Rock Volume is usually the key driver in field/prospect size, therefore depth conversion is often responsible for the bulk of the uncertainty in estimation of reserves/resources. Depth conversion is key to well prognosis and a realistic range is needed for any project. It is therefore vital to derive an estimate of the uncertainty in the depth horizons of interest.
Sensitivities based on single deterministic cases is often prone to error and only a limited number of test cases can be run. It is also time consuming and tedious.
Velit’s approach is to develop a reasonable estimate of depth uncertainty based on a large number of depth models derived from one or more depth conversion schemes.
Velit offers a range of depth conversion functions including techniques such as: Faust, Slotnick, Uplift, Zechstein Compositional Method, etc. With the optimize technique the users can fit sonic logs, uncalibrated sonic logs, and optimise for any 2 parameter Velocity-Depth function. This creates very robust velocity models and is the best technique for tackling geological sequences with an increasing velocity trend with increase depth.
Velit enables the use of stacking velocities for depth conversion and can create pseudo wells that can give additional control away from a user’s known data points. This means a user can utilise well-based methods and leverage the stacking velocity data to have a more robust velocity model, than using either data separately.
The Wizard within Velit forms an excellent introduction to depth conversion techniques and the capabilities of the software and covers most depth conversion scenarios, allowing the user to depth convert layer by layer quickly and assists the user in understanding the velocity modelling methods available.
Velit can create 100’s of equally probable depth conversion models. The depth conversion software reduces risk with the Analysis Tools in providing a Probability of Closure map for spatial uncertainty, the P10/P50/P90 and where the starting model is situated in proximity to the P50, for confidence in the Best Technical Case and the software can determine which layer within the model has the biggest impact on the Gross Rock Volume of the reservoir.
Velit is completely transparent and users can see everything that is going in to the depth conversion. This means they can provide audit trails and technical reports of exactly how their depth model was created. They can also use the Workflow Builder to re-run a model with new data added to it, at the click of a button. This can save users a lot of time.
Velit allows users to depth convert 2D lines as well as 3D data. This technique can also handle faults, salt diapirs and Multi-Z pods of velocity information to create “2D-3D” velocity modelling situations that are highly complex and tackle any geological scenario!
Full Velit Depth conversion training and courses are available. Contact us for a demo today!
