## 3 Results and Discussion
### Effect of Wettability on T\({}_{2}\) Distribution and T\({}_{2}\)LM
The intensity of the T\({}_{2}\) signal for the oil phase increases as oil saturation increases, causing the bulk relaxivity of oil to be at its peak. The increase in the oil phase causes a consistent non-linear increase in the T\({}_{2}\)LM. However, it is not as pronounced due to the additional contribution of the surface relaxivity influence of water to the wettability phenomenon. Hence, there is a slight and consistent increase in T\({}_{2}\)LM readings close to the single exponential time for water. In light of this, it is instructive to state that at high water saturation, residual oil in existence within the reservoir pores is non-wetting. The residual oil is subsequently only exhibiting bulk relaxation, resulting in a positive trend as a function of increasing water saturation at the top part of the trend (0.85 Sw and above). When ascribed to weakly water-wet conditions, this analysis results in a negative trend as a function of increasing water saturation. This trend is because an increased volume of oil wetting the pore surfaces leads to the influence of surface relaxivity on oil and water. Therefore, weakly water-wet to mixed wet will have a flat or negative gradient because no spontaneous imbibition occurs at these wettability conditions. This study did not investigate oil-wet conditions due to the unavailability of cores that have been experimentally analysed for wettability. However, the contributing effect of surface relaxivity on oil will be pronounced for oil-wet conditions, typically the case in carbonate reservoirs. Hence, an increase in oil saturation will invariably cause a decreasing trend in T\({}_{2}\)LM as a function of decreasing water saturation. This postulation agrees with the reported research by [PERSON] et al. [58], where several core analysis investigations into the effect of wettability on T\({}_{2}\) distribution were conducted. With the information and methodology detailed in this research, wettability conditions can be established at the field using water saturation and NMR T\({}_{2}\)LM log data. Instances, where high water saturation depicts high NMR T2 LM measurements, indicate a non-linear correlation between NMR T\({}_{2}\)LM and water saturation, which can help identify the different wettability conditions in a reservoir. For a mixed wettability condition, surface relaxivity will depend on fluid volume wetting the pore spaces. Although this analysis is based on water-wet conditions, the subsequent discussions will illustrate how heterogeneous wettability states can be classified. Development of Methodology to Establish a Relationship between Water Saturation and NMR T\({}_{2}\)LM  
Using wireline log data from the Coniston well, the applicability of the postulated empirical equation was verified. Based on the in-depth literature review, it is known that bulk oil has a slow T\({}_{2}\) relaxation time. The opposite occurs for water which has a relatively faster T\({}_{2}\) relaxation time. Further analysis has established that the wetting fluid experiences surface relaxivity for strongly water-wet conditions. Whereas the non-wetting fluid decays at its exponential bulk relaxation; hence, there is a shift in T\({}_{2}\) relaxation time towards the high T\({}_{2}\) readings in an increasing oil saturation. This indicates an increase in T\({}_{2}\)LM as a function of increasing oil saturation. This agrees with the extensive core analysis carried out by [PERSON] et al. [58]. The hydrocarbon coexisting with the water will influence the T\({}_{2}\) relaxation times. Hence, the rate of increase or decrease will be affected based on which fluid wets the pore spaces. Based on Figure 9, the trend line for the shift in T\({}_{2}\)LM as a function of decreasing water saturation primarily indicates a water-wet condition for both the gas and oil zones agreeing with core wettability measurements. For the delineated reservoir zones, the different gradients in plots indicate the existence of heterogeneous wetting conditions (see Figure 10).