An analysis of protocols for the calculation of tract participation

Several different methods have been evaluated for calculating tract participation in diverse reservoir situations where a unitized field straddles a domestic or international licence boundary. There are three key elements. The first concerns the choice of a static or dynamic basis for tract participation or a hybrid method that falls somewhere between the two. The second involves the introduction of any conversion or weighting factors that are designed to take account of systematic differences in hydrocarbon type or reservoir quality across the field. The third relates to adopted practices for the volumetric calculations, specifically the equity-sensitive areas of scale considerations, fluid levels, net-to-gross ratio, and reservoir mapping. These key elements are analysed from the standpoint of securing a fair and equitable (re)determination of tract participation. Recommendations for a more technically substantive approach reinforce the pareto-efficiency of unitization, so that the cost of the exercise to each partner is a good deal smaller than the greater revenue that can be secured by that partner through the integrated development of a straddling field. However, every unitization and redetermination situation is different, and each case should be considered on its merits if maximum benefits are to be attained.