Petroleum Systems Analysis and Modelling

DAY 1

General introductions

1. Introduction and the basics: a brief introduction of the topics and concepts that will be covered during the course
2. Risks, Volumes & Uncertainty: Explanation of how the terms Risk and Uncertainty are used in exploration. Presentation of a practical workflow to assess prospect risks. Introduction to the calculation of prospect volumes, and a discussion of pitfalls and biases in estimation.
3. Prospects and Plays: Module to stress the importance of understanding prospect details in the context of basin type and basin development, and of the “play” to which the prospect belongs.
4. Prospects and portfolios: Different prospect categories (near-field, proven play, greenfield, etc) followed by a discussion of ranking criteria for prospects.

DAY 2

Recap Day 1

1. Traps: the main uncertainty in assessment of prospect volumes is the uncertainty of the gross rock volume. The importance of recognizing potential spill- and leak-points that may control the HC-water contact is stressed. A “read thread” prospect is introduced followed by an exercise to identify potential spill- and leak-points.
2. Traps in important HC provinces: examples of working traps in rift basins, sag basins, passive margins, deltas, deep water settings and carbonate settings.
3. Reservoirs: explanation of the main reservoir parameters (thickness, N/G, porosity, permeability and reservoir geometries). Modern probabilistic volume assessment tools make it possible to input detailed reservoir data. Correlation (dependency) between reservoir input parameters, and its effect on calculated volumes, will be discussed.
4. Reservoirs in important HC provinces: examples of reservoirs in different basin types and depositional settings from around the globe: rift basins, deltas, deep water settings, carbonate provinces.

DAY 3

Recap Day 2

1. Seals: In exploration, seals are often not given the attention they deserve. Mechanisms of leakage will be discussed: permeability seals, hydraulic fracturing of seals. The role of seals in the differential entrapment of oil and gas will be discussed. Fault seal mechanisms are presented with an exercise to calculate Clay Smear Potential (CSP) at several points along a fault plane.
2. Pressures and overpressures: Pressure gradients and how they can be used as an indication to determine fluid contacts in traps. Mechanisms of overpressure development, and the provinces where they typically occur are presented. A discussion of the meaning of the fracture gradient and Leak-off Pressures follows.
3. Seals & Pressures in important HC provinces: examples of working seals in a range of different basin types and settings from around the globe, with examples of cases where seals are breached and of cases where differential leakage of gas has allowed oil to be trapped, despite abundant gas charge.
4. Charge: The conditions under which source rocks can be deposited and preserved in the subsurface as well as the different source rock types (I, II and III) and their typical expulsion products are discussed. There is an exercise on constructing a burial diagramme, and the effect of inversion (uplift and erosion) on hydrocarbon charge is explained.

DAY 4

Recap Day 3

1. Charge in important HC provinces: Examples of charge in different basin types and depositional settings from around the globe. Includes an exercise on predicting source rocks from a regional seismic section.
2. Risk assessment – practical group exercise: The read thread prospect that has been introduced earlier will be used for assessment of the chance factors for trap, reservoir, seal and charge. Volume assessment – back-of-the-envelope calculation: a short session where the participants are asked to calculate low, most likely and high volumes of a prospect.
3. Volumes and Portfolios: An explanation in a practical manner how prospect volumes can be added. Some mistaken, but common, practices will be highlighted. Prospect dependencies and their effect on prospect additions will be discussed.

DAY 5

Recap Day 4

1. Exploration economics: An introductory module on exploration economics with an explanation of the main factors that control the economic viability of prospects, and of the terms Net Present Value (NPV) and Expected Monetary Value (EMV). The module includes an exercise on calculating the EMV of a prospect.
2. Geophysical evidence: The presence of “Direct Hydrocarbon Indicators” (DHIs) may provide good evidence that trapped hydrocarbons are present. Pitfalls are explained with real examples and an approach for determining an increase of the Probability of Success (POS) is presented. The module also touches upon the impact of Controlled Source Electromagnetics (CSEM) on prospect POS.
3. Local prospect examples: Participants have an opportunity to bring in examples of prospects they may be working on, to discuss specific risk and volume assessment issues in the light of what has been learned.
4. Look backs: A short module on how pre-drill predictions can and should be compared with post-drill well findings. It is stressed that we can only improve our pre-drill predictions if we know if there is any bias in our predictions.