Fractured Reservoir Simulation and Field Development, Natih Field, Oman

Abstract

Further development of the fractured Natih field requires a good understaliding of the historical contributiolis from gas/oil gravity drainage and water/oil displacement. A history match of the field has been made using a fractured reservoir simulator, which apart from dual porosity, can model dual permeability and block-blook interaction. Several studies aimed at describing the reservoir in detail were required before simulation could start. The history match shows that gas/oil gravity drainage has been about twice as effective as water/oil displacement. This figure is in good agreement with the gas and water sweep data derived from recent gas saturation and water saturation measurements in the field. Prediction runs show that promoting gas/oil gravity drainage by lowering the fracture oil rim is an attractive way to further develop the Natih field.

A Switch from Verticals to Dual Lateral Producers Accelerate Oil Production and Reduces UTC for Natih Field

“…4,5) confirmed that full GOGD with oil rim lowering was the most attractive way for the continued development of the Natih Field. It was, thereafter, implemented in the Natih-A, together with crestal gas injection and peripheral water production.…”

“…The initial production behavior of the Natih filed (Figs. [3][4][5] showed well off-take up to 2000 m3/d and total field production building up to more than 15000 m3/d. Early developing water cut and fast movement of fluid contacts were totally in line with a fractured reservoir.…”

“…Using iterative methods of adjusting parameters in combined GOGD models to match observed saturation's, it was concluded that gas/oil gravity contributed 40-65% to total production [Ref. 4]. …”

“…Based on the 2D dual porosity-permeability simulation (Ref. 4) it was found that the optimum position for the fracture OWC is at the 50% saturation level in the matrix, at 760 mss level.…”

The Challenges and Way Forward of Horizontal Dual Lateral Wells in Fahud Matrix Reservoir

“…The voidage created in the matrix pore space is replaced by gas, which is injected into the fracture system (Ref. 3). Generally GOGD wells come on stream with low nett production, high BSW and low GOR.…”