Core Analysis

Core and thin section descriptions and interpretations are key components of regional to field-scale studies because depositional and diagenetic facies, stratigraphic architecture and fracture networks usually control porosity and permeability distributions and reservoir performances.

A fundamental understanding of the reservoir architecture and dynamic behaviors can only come from accurate core&thin section descriptions and interpretations.

  
Core description & interpretation
G.E.Plan Consulting can log and interpret cores and calibrate them to electric and image well logs.Main features described on cores are: depositional textures, major grain types and granulometric ditribution, sedimentary structures, sorting, lithologic composition, structural features, pore types and visual porosity. These information are used to interpret the depositional environments and water depth and to predict the distribution of sedimentary bodies.

Using an accurate core descriptions we can place them in the reservoir architecture by using a sequence stratigraphic approach based on the hierarchical development of sequences through base-level transit cycles of varying frequency (short-term to long-term).

Part of our core studies is devoted to an analysis of 2-D stacking patterns of facies in order to develop a rock-based sequence stratigraphic framework. We identify facies successions, or cycles, and the important hiatal surfaces (exposure, erosional, sediment-starved, firmgrounds and hardgrounds) that bound stratal units, or cycles.

In order to capture detail, cores are usually logged at a scale of 1:10.

Petrography (thin section description & interpretation)

We use thin-section descriptions to address the mineral constituents, allochems, texture, sorting (or crystal size range), pore types and the type and abundance of pore-filling cements or alteration/residual products. This is the base for our diagenetic interpretation, or paragenetic history.

We recommend working with blue-dyed epoxy impregnated thin sections in order to highlight porosity networks. We also recommend that carbonate thin sections be stained for carbonate mineralogy (Alizarin Red-S and potassium ferricyanide) and siliciclastic thin sections be stained for potassium feldspar (sodium cobaltinitrite).