--> Abstract: Improved Characterization and Modeling of Unconventional Fractured Jurassic Reservoir, by Saad A. Matar and Fahed Al-Medhadi; #90077 (2008)

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Improved Characterization and Modeling of Unconventional Fractured Jurassic Reservoir

Saad A. Matar* and Fahed Al-Medhadi
KOC
*[email protected]

The development of a fractured reservoir is, in most cases, a hazardous task due to the difficulty in understanding the organization of the natural fracture network and its exchange with the matrix. This study demonstrates the first ever attempt to model a complicated naturally fractured reservoir in Kuwait. It illustrates the modeling methodology, history matching and future performance prediction of Najmah-Sargelu reservoir in Minagish field in western Kuwait. The Najmah-Sargelu reservoir was discovered in 1985 and it contains commercial quantities of light oil. The reservoir is composed of tight carbonate layers interbedded with organic-rich source rocks that are transected by subvertical fracture and fault sets of different sizes, orientations and intensity. Initial reservoir pressure (12,500 psia) has dropped drastically to 7,000 psia in the crestal area during natural depletion through production; but it is still greater than the asphalten onset pressure (approximately 5,000 psia through lab tests) or saturation pressure of 2,600 psia.

This presentation discusses the development of a dual-porosity model for the Najmah-Sargelu reservoir using the discrete fracture network model. It discusses how the model can be used to narrow the uncertainties in reservoir properties and therefore develop an off-take strategy with different drive mechanism that improves recovery. In particular, it will be shown how the model has helped to estimate the matrix contribution to fluid flow. Rock wettability, as well as average permeability, were tuned to achieve a good history match of water production. The reliability of the model to predict the future reservoir performance has recently been tested with the successful forecast of water breakthrough of two producers.

 

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain