About Petroleum / Fluid Systems Analysis
Our Industry’s product is a fluid which, when brought from the subsurface to the surface, exists as a petroleum liquid and / or gas. The goal of Petroleum Systems Analysis (PSA) is a holistic and quantitative understanding of how petroleum fluids form in the source bed, move from source bed to trap where they are retained, and accumulate in the reservoir from which they are produced.
The Petroleum System
A working Petroleum System requires three System Elements to come together to form an accumulation:
- Charge System
- Trap System
- Reservoir System
Each System Element has a rock and a fluid component that is needed to understand it. Historically many geoscientists have focused on the ‘rock’ part, often leaving a knowledge gap – which t!Ps™ aims to help fill – in understanding the ‘fluid’ part. t!Ps™ believes failure to recognize these ‘gaps’ plays a significant role in the poor historical performance of the Industry as a whole, in terms of dry hole drilling and volume under-prediction. Fluid Systems Analysis (FSA) is the enabling know-how that blends geology, organic geochemistry and numerical simulation of physical processes – the latter usually referred to as ‘Basin Modeling’ – in order to understand the fluid part of the Petroleum System. Although no one discipline ‘owns’ the entire Petroleum System evaluation, geoscientists who understand the Fluid System are ideally placed to view the entire Petroleum System holistically – hence the two terms are sometimes used interchangeably. Having outlined a process to understand the Petroleum System, the next step is to organize, define roles and enable the team to follow it, including the Petroleum / Fluid Systems Analyst of course! Every member of a multi-disciplinary geoscience team has a role in an opportunity assessment. The diagram below shows a ‘fully staffed’ model where generalists, geoscience experts and an Analyst work in either a leading (Green), support (Yellow) or passive (blank) role to deliver the various components of the Volume and Value calculations and its carefully linked Risk assessment. (The abbreviations are the same as those used in the Volume and Rate equations). By ‘following the fluids from source to trap’ within the Petroleum System, the Analyst is literally involved in every part of the evaluation. The next diagram focuses specifically on the Analyst within the team, with a very brief summary of the types of activity in each ‘Risk Element’ evaluation. where A = area dof = fractional degree of fill h = net thickness of reservoir phi = fractional porosity of net reservoir Sw = fractional water saturation of net reservoir fvf = dimensionless formation volume factor of reservoir fluid in net reservoir u = viscosity of reservoir fluid in net reservoir Far from being a ‘specialist’ role, this model requires both a deep and broad contribution from the Analyst in leading or supporting the required workflows. This is a big ‘ask’, but the alternative is an evaluation with hidden loose ends, with only luck to fall back on. To complete the team’s understanding of the Petroleum System, the Fluid Systems Analys t must be able to:
- Numerically model the physical processes that drive basin evolution – the Petroleum System is a machine driven by heat and gravity
- Within this heat and pressure framework, understand the chemical and physical processes that govern petroleum generation and expulsion, composition and physical properties, migration, entrapment and leakage
- Do this within a solid geological framework
The deepening needed to learn the component skills and the broadening required to integrate them into a Fluid Systems understanding come with time. This is a relatively new discipline and current practitioners – Andy included – have found themselves there by necessity, rather than grand organizational design! The triangle of skills is the base of a tetrahedron, so the career pathway is analogous to the ascent of a pyramid. t!Ps™ Products and Services can help you make the ascent! Organizations can foster the needed skills in two ways:
- Develop individuals over time as holistic Petroleum / Fluid Systems Analysts, as advocated by Andy in presentations and publications in the early 2000’s. This is the way that Andy’s career evolved and while this is a challenging role, it ensures a holistic approach and makes it more likely that individual teams can have an embedded core member Fluid Systems Analyst
- Perform the Analysis via a combined team with permutations of generalist geologist, specialist geochemist and specialist basin modeler working together. Truly excellent teamwork is required to achieve the same holistic and integrated understanding as a single PSA can provide, especially if the specialists are internal or external consultants.
t!Ps™ aims to provide the Services and Products to support both models, given the organizational constraints of different E&P Companies. Of course there is a third option for an E&P company: just focus on the more familiar elements of ‘Rock’ geoscience and live with inherent risks!