## 6 Conclusions  
Overall, the fracture analysis conducted on the Niah-Subis Limestone complex provides an excellent analogue study for the Oligocene-Moocene carbonate reservoirs in Central Luconia Province. Using DEM data and outcrop observations, the combination of lineament analysis and karst features was analysed and delineated. The properties of fractures were then compared at both the regional (macro-scale) and outcrop (meso-scale) levels using 2D DFN models and topology analysis. The findings of this paper have concluded that:  
* Integrating the outcrop and regional lineament analysis allows for a more detailed description and characterisation of the sub-seismic scale complex fracture network and can reduce the observational gap between well and seismic data;
* Karst features such as dolines, caves, passages, and speleothems are highly influenced by the intersection of fractures, major orientations, and the surface and underground drainage systems. The paleo-karst fracture networks are also strongly impacted by karst dissolution;
* Fracture parameters, including length distribution, density, intensity, and connectivity, are mainly scale-independent and vary spatially;
* Both regional lineament and outcrop fracture analyses in this study demonstrate that the fractures are isolated, with little connectivity between them. This should be reconsidered as limitations on outcrop accessibility can influence the results of the I-X-Y model;
* The small contribution of total fractures to the fracture network connectivity and the discrete behaviour of paleo-karst fractures has emphasised the importance of incorporating the matrix porosity across multiple scales of fracture network modelling in future studies. This should be performed for a better solution in upscaling the fracture-vug network model and to reduce the underestimation of models;
* Lastly, the fracture network models can predict the fluid flow and the potential karst feature alignment by incorporating the reservoirs' permeability and porosity.  
Conceptualization, P.Y.O. and S.N.F.J.; methodology, P.Y.O.; software, P.Y.O.; validation, P.Y.O. and S.N.F.J.; formal analysis, P.Y.O.; investigation, P.Y.O. and S.N.F.J.; resources, S.N.F.J.; data curation, P.Y.O. and S.N.F.J.; writing--original draft preparation, P.Y.O.; writing--review and editing, S.N.F.J.; visualization, P.Y.O.; supervision, S.N.F.J.; project administration, P.Y.O. and S.N.F.J.; funding acquisition, S.N.F.J. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the YUTP-FRG Grant entitled Assessment of CO\({}_{2}\) Storage Potential in Naturally Fractured Carbonate Reservoir Through DFN and Dual-Porosity (Seismic) Model with the Cost Centre 015 LC0-466 under Yayasan Universiti Teknologi PETRONAS (YUTP).  
Not applicable.  
The work contained in this paper is part of a PhD research project supported by the Centre for Subsurface Imaging (CSI), Universiti Teknologi PETRONAS, which provided research facilities and supported during fieldwork in Niah, Sarawak on February, 2023, with a research fund under cost centres of 015 LC0-466 (YUTP-FRG) and 015 PBC-021 (YUTP-PRG). The authors [62] also acknowledge the open-source tool FracPaQ version 2.8 for its use in fracture topology analysis.  
The authors declare no conflict of interest.