Integration of Time Lapse Seismic and Dynamic Reservoir Model Facilitate EOR Immiscible Water Alternating Gas (IWAG) Programme in Oil Field, Offshore Peninsular Malaysia

Shahud, Noreehan ¹; Ismail, Russikin B.¹; Singh, Yeshpal ¹; Ibrahim, Ramli B.¹
(1)Petronas Carigali Sdn Bhd, Kuala Lumpur, Malaysia.

The integration of geoscientific and reservoir engineering data is critical for reservoir characterization and management in the mature oil field. The flood front movement monitoring through Immiscible Water Alternating Gas (IWAG) injection is a major challenge due to sparse well locations and reservoir heterogeneity. The selected field was discovered in 1981 and is on production since 1991 with cumulative production around 20% of STOIIP. A pilot IWAG injection project was carried out in the sub-block of the main reservoirs for a period of four (4) years successfully as one of iniatitives for enhanced oil recovery (EOR). As a result, full field injection plan has been formulated.

For effective reservoir management, it is very important to detect and monitor IWAG injection effect. In order to understand the potential uncertainty and for effective planning prior to actual project implementation, a time-lapse seismic feasibility study was carried out. Rock physics modeling played a critical role for establishing the relationship between elastic properties and pressure/saturation effects simulated in dynamic reservoir modeling. It has been observed that two years IWAG injection cycles may lead to cumulative acoustic impedance changes of 6%-8%. The present study identifies the factors contributing to the chances of success (COS) of the project. The time-lapse seismic feasibility outcome ensured both technical and economics success and further prompted for monitoring of full field implementation IWAG injection.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.