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Integrated Geological Modeling of Middle Marrat Carbonate Reservoir in Abdulyiah Field, West Kuwait

Al-Muraikhi, Rasha 1; Jalil, Abdul Aziz Abdul 3; Fahmy, Mahmoud 4; Al- Rukaibi, Anas *2
(1) KOC, Kuwait, Kuwait. (2) KOC, Kuwait, Kuwait. (3) KOC, Kuwait, Kuwait. (4) KOC, Kuwait, Kuwait.

This paper presents construction of a fine-grid geological model of Middle Marrat Carbonate

Reservoir in Abdulyiah Field using an integrated approach incorporating several innovative work flows such as: 1) sequence stratigraphy based depositional framework modeling derived from well log and core data 2) detailed core to well log calibration for rock-typing using supervised neural network technique 3) re-interpretation of seismic data including 3D fault mapping, 4) post-stack seismic inversion for quantitative estimation of porosity, 5) property and facies modeling using variogram analyses 6) co-kriging of seismic inversion porosity to guide porosity distribution away from wells 7) Gaussian simulation for populating porosity, permeability and water saturation, and 8) reservoir volumetrics including uncertainty analysis.

The new 3.2 million cell stochastic geological model has high vertical resolution with 140 layers having 2 feet average cell thickness in the payzones. The net reservoir thickness varies widely between 30 to 100 feet as observed in the wells with large inter-well spacing of 1 to 2 km. The reservoir is heterogeneous with 20 to 60 feet vertically stacked carbonate para-sequences where porosity is mainly developed in packstone-grainstone shoals. Inter-granular porosity forms the main pore system; however inter-crystalline porosity is locally developed in dolomitic layers due to digenesis. The model helped in understanding the lateral facies variations through seismic derived porosity inversion particularly away from well control area. Based on this model, a new deviated well has recently been drilled successfully in reservoir shoal sweet-spot where new core is acquired for special core analysis. Detailed core description of this well was used to test the validity of geological model, particularly the rock types prediction and porosity development. Based on this high resolution geological model, the reservoir simulation is being undertaken for optimized field development including water injection option for pressure maintenance.

 

AAPG Search and Discovery Article #90141©2012, GEO-2012, 10th Middle East Geosciences Conference and Exhibition, 4-7 March 2012, Manama, Bahrain