*1.2.1 Fabric domain mapping*

The proposed mapping of fabric domains includes scanning of prepared thinsection micrograph at a resolution scale of about 5 mm to have clearer image resolution (**Figures 2–6**). This will enable to visualize completely all the different grain assemblages or colonies at a single glance. It is also achievable when a thin-section micrograph is systematically gridded to capture images under a polarized microscope, but will be cumbersome when attempting to join all captured micrograph images

#### **Figure 2.**

*Showing fabric domain types present in the reservoir rock sedimentary facie; massive coarse grained sandstone (MCGS) from Offshore, Malaysia. In yellow dotted-line is the Random domain, in red dotted-lines in the Clastssupported domain and in blue dotted-line is the Matrix- supported domain.*

#### **Figure 3.**

*Showing fabric domain types present in the reservoir rock sedimentary facie; massive Burrowed medium grained sandstone (BMGS) from the Offshore, Malaysia. In yellow dotted-line is the Laminar/matrix supported domain, in red dotted-lines in the Clasts-supported domain, in black dotted-line is the fractured-dominated domain and in purple dotted-line is the random domain.*

#### **Figure 4.**

*Showing fabric domain types present in the reservoir rock sedimentary facie; parallel laminated friable fine grained sandstone (PLFFGS) from Offshore, Malaysia. In yellow dotted-line is the Matrix supported domain, in red dottedlines in the Clasts-supported/Fractured-dominated domain, and in purple dotted-line is the random domain.*

at 500-μm magnification into a single micrograph due to edges-effect difference as can be easily be achieved using a high-resolution scanning machine (**Figure 7**). The scan micrograph image carefully visualizes all grain assemblages or pattern nature

#### **Figure 5.**

*Showing fabric domain types present in the reservoir rock sedimentary facie faintly laminated fine grained sandstone (FLFGS) from, Offshore, Malaysia. In yellow dotted-line is the Random/fractured-dominated domain, in red dotted-lines in the matrix-supported domain and in deep blue dotted-line is the Clasts-supported domain.*

#### **Figure 6.**

*Showing fabric domain types present in the reservoir rock sedimentary facie massive very fine-grained sandstone (MVFGS) from Offshore, Malaysia. It exhibited only two (2) fabric type Matrix-supported and Fractureddominated domains.*

**Figure 7.** *Schematic diagram showing study area under the microscope and scan area for fabric domain type mapping.*

with reference to the dominant grain packing, contacts, sorting, orientation, matrix distribution, compaction and intergranular pore-spaces will be characterized into fabric-type domain (**Figures 2–6**).

In a practical approach to achieve mapping of the variable domains in a sedimentary facie, each representative micrograph (s) is scanned using a high-resolution scanning machine as earlier mentioned. The output gives a panoramic view or coverage of the entire aggregates of geometric and spatial configuration on the micrograph; thereby, a careful observation of the different domain fabric type will be mapped out clearly (**Figures 2–6**).

#### *1.2.2 Fabric domain types*

The reservoir sandstone facies of the West Baram Delta as an example is characterized into five fabric domains as in subsection 1.2.1 based on the dominant textural features (grain size, shape, grain sorting, grain-contact, grain orientation, pore space, and matrix content) namely the clasts-support, random, matrix-support, and laminar and fractured-dominated fabrics. The clasts-support (types 1 & 2), matrix-support (types 1 & 2), and random and fractured-dominated fabric (types 1 & 2). Subtype (type 1 & 2) for the clasts-support, matrix support, random and fractured-dominated are grouped based on their variances in percentage composition of matrix content (**Table 1**).

From the above fabric domain-type mapping, it indicates that a single thin micrograph is not ideal to fully represent a single rock fabric type. This being that there are variable and discrete variations in physical grain assemblages and perhaps their properties within the micrograph. Thus, changes and variations will occur within the developed different fabric domains across the entire micrographs. It occurs that the multiple fabric domain type facilitates existence of multiple hydraulic fluid units (HFU's) [22] orchestrated mainly by the variable difference or in some case similar


*Sedimentary Rocks and Aquifers – New Insights*

