This paper will illustrate the collaborative approach taken by an integrated team (operator and service company) charged to demonstrate, within a one-year time period, measurable improvement in well productivity in the Saih Rawl field of Oman. Although the field has been producing for more than five years, the results shown are based on a one-year application of a systematic approach to field optimization. This process is the dynamic integration of historical data and new information, technologies, and engineering diagnostics to systematically identify, layer-by-layer, key parameters affecting productivity and to optimize performance based on "present-state" analyses. In doing so, the program has produced some of the highest productivity wells in the field's history.

Oman has developed into a fast-paced fracturing arena, with challenges similar to those encountered in the tight gas fields of south Texas in the United States. Well productivity is highly dependent on hydraulic fracturing effectiveness and operating practices. Understanding the resultant hydraulic fracture effectiveness is increasingly complicated by the changing mechanical and reservoir properties related to depletion and intralayer communication (crossflow).

Gas is produced in the Saih Rawl field from two distinct main reservoirs: the Barik and Miqrat formations. The Barik formation, at depths from 4500 to 4900 m, is composed of stacked sandstone packages with varying shale content separated by relatively thin heteroliths (sandstone/shale mixtures) of 3 to 7 m thickness. These heteroliths are believed to provide pressure barriers to the various flow units observed in the Barik formation. The Barik formation produces gas of varying richness from most of its units, with a high condensate content produced from layers that are producing currently below dewpoint. On the other hand, the Miqrat formation, found at depths >5100 m, produces lean or dry gas. The combination of relatively low and heterogeneous permeability along with complex hydraulic fracture height growth makes it necessary to perform ad hoc, multistage hydraulic fracturing treatments and to produce these wells commingled to be commercially economic. A systematic approach, incorporating historical pressure trends by unit and theoretical assumptions, validated by indirect field evidence, to onsite decision-making has resulted in the placement of more effective fracture treatments in an operationally efficient manner. The results of these efforts yielded the highest producing well in the field's history in an area of known depletion; the highest-rate Miqrat production well, an overall improvement of zone productivity, and a better understanding of the factors impacting productivity, layer-by-layer, in the Barik and Miqrat formations.

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