Rock physics driven software and solutions for carbonates | Ikon Science

Carbonates

Carbonate plays and Ikon Science

Ikon Science’s unique Quantitative Interpretation capabilities have proven to be ideally suited to characterise and predict many carbonate plays across the world. Some of the most prolific oilfields in the world are carbonate reservoirs. With the combination of horizontal drilling and reservoir stimulation techniques, tight carbonates can now be produced with better economics. Carbonate reservoirs are challenging to evaluate, complex to model and require performance monitoring during production. 

It starts with rock physics

Ikon Science has been successful characterising and predicting carbonate-rich facies, thanks to its unique geoprediction approach; identifying and modeling pore aspect ratio, secondary porosities, and multi-mineral calcareous facies via extended Rock Physics models (Xu- Payne / Kuster-Toksoz) supported by Differential Effective Media (DEM) and Self-Consistent Approximations (SCA).

Carbonate-rich facies are typically composed of complex, heterogeneous sedimentary (and sometimes metamorphic), rocks with unique pore types developed from rock-fluid interactions. By understanding their provenance, depositional environment, and pressure/temperature/stress regimes, Ikon Science enables a reliable prediction of the distribution of mineral composition, pore types, and brittleness to ensure optimal well completion and reservoir performance.



Understanding porosity

The ability to model expected pore types from compaction, dissolution, diagenesis, or cementation of a carbonate rock is critical in order to assess how hydrocarbons will flow during the production phase. Variations in these properties can result in by-passed resources.

Predicting microcracks

The ability of fluids to flow in a carbonate reservoir is highly predicated on the existence of fractures in the rock unit. Open microcracks will facilitate flow, and the ability to locate brittle areas in the reservoir is crucial for field development planning. Rock physics models such as Xu-Payne and modified Kuster-Toksoz make it possible to characterise pore types by aspect ratio, classifying stiff, intra-particle, and microcrack porosities in carbonates, are embedded in the RokDoc modeling software.


Probability of porosity > 5% predicted from a single-property (AI) stochastic inversion using RokDoc. (Hardy, 2013).

4D reservoir monitoring and modelling

Reliable carbonate reservoir models developed during the appraisal and development of a field require validation during the production phase, using 4D seismic to identify bypassed compartments and water production through major fractured zones. Ikon Science’s ChronoSeis 4D forward modelling system, embedded with robust 4D rock physics capabilities, allows geoscientists to predict pressure, saturation, or compaction variations prior to committing to a new seismic survey, or match the history of production from one or more wells and seismic surveys.

Getting fractures right

By far the greatest contribution to hydrocarbon flows within carbonates comes from fractures in the reservoir, which also influence the flow rates that can be sustained while avoiding the bypass of low permeability compartments. A proper understanding of natural fracture systems, supported by a comprehensive geomechanical model, informs drilling decisions.

A Xu-Payne rock physics template overlain on a crossplot of well log data helps to decipher pore geometry in carbonate formations. The solid reference line corresponds to a reference pore shape with a fixed aspect ratio of 0.15. Dashed lines indicate a range of constant pore aspect ratios with stiffer pore shapes (e.g. vuggy porosity) plotting above the reference line and softer pore shapes (e.g. cracks) plotting below the reference line.

RokDoc for carbonates

Ikon Science has pioneered the application of rock physics since 2001, and this expertise is present both in the industry-leading RokDoc software platform and among Ikon Science teams around the world. By taking into account the characteristics of a specific carbonate facies to calculate accurate poroelastic and mechanical properties, Ikon Science makes it possible to comprehensively characterise carbonate reservoirs, resulting in fewer surprises over the life of the field.