Prospect & Play Analysis
Most of our work consists of prospect & play assessments. Risking fault seal is based upon our large proprietary database of fault seal behavior in existing fields.
Routine Fault Seal Analysis
Routine fault seal analysis involves the construction of fault plane profiles to establish juxtaposition relationships and quantitative fault seal analysis to estimate gouge composition and seal behavior. Seal behavior is risked using a seal/leak threshold empirically determined from correlating known seal behavior and gouge compositions in existing fields.
Algorithms allow risking both cross seal/leak (leakage across the fault zone) and dip seal/leak (leakage up along the fault zone). Both types of seal/leak have different risk and different types of fault dependent leak points.
Assessing Percent Fill
We are able to risk not only success/failure of a prospect dependent upon a sealing fault but also percent fill, hydrocarbon column heights, and charge that are dependent upon fault dependent leak points, fault seal capacity, displacement, structural style, and fault dependent migration pathways into a trap.
Different types of fault dependent leak points allow a fault to trap a finite column of hydrocarbon but spill the excess through the fault zone. These leak points can be predicted using routine fault seal analysis.
Hydrocarbon column heights are also limited by gouge composition and the seal capacity of the fault. Even sealing faults can seal only limited columns of hydrocarbon.
Recent analysis of fields in the Gulf Coast has shown an empirical relationship between hydrocarbon column heights trapped against faults and displacement and structural style. Faults limit percent fill.
Migration & Charge
Fault seal affects not only entrapment but also migration and charge. There are numerous examples in our database and Fault Seal Atlases of faults preventing charge of a compartment in a field, or charge of a prospect. Hydrocarbons may be trapped down dip against a sealing fault rather than migrating into a more obvious structural high. Hydrocarbons may also be deflected away from one trap and towards another.
Prospect and play assessments may also require analysis of faults along the migration pathway into the trap as well as the major boundary fault(s) upon which entrapment depends.
The ability to risk fault seal is only as good as the structural and stratigraphic control used to analyze the faults. The confidence with which you can risk fault seal behavior is obviously higher in a mature basin than in a frontier basins.
Where stratigraphic control is limited, min/max/most likely cases are analyzed using synthetic logs to evaluate seal risk. Risk is calculated for a range of possible stratigraphies and for a range of possible fault displacements.
In addition to the SGR threshold, we have found other empirical relationships that allow you to risk seal. Displacement, structural style, regional stratigraphic facies, gouge seal capacity, and hydrocarbon phase are all related to seal and percent fill. These variables place constraints on prospect risk, seal behavior and percent fill.
In both the Gulf coast and the North Sea/Norwegian Sea we have found that seal risk and hydrocarbon column heights are related to regional stratigraphic facies patterns. Regional seal risk maps reflect broader patterns of seal behavior. These seal risk maps can be used when detailed stratigraphic data are limited.
We can provide either complete prospect assessments, including our calibrated thresholds for seal/leak and analogs from our databases, or simply fault plane profiles and quantitative fault seal analysis data for your own interpretation. The new QuickLook software is used at an early stage in prospect evaluation before you are able to make accurate depth-structure maps of the prospect. QuickLook focuses your interpretation on the critical portions of the fault, saves time and increases efficiency. QuickLook can also enable you to rank multiple prospects and focus your attention on the viable ones rather than the high risk prospects. QuickLook is ideal for evaluating prospects with structural and stratigraphic uncertainty using stochastic analysis.
In addition to routine fault seal analysis
Our consulting services also include: