Modeling and Validation of Fluid Flow-Geomechanics of Mauddud Reservoir in Sabriya Field

Ibrahim, Hossam El-Din¹; Ashok, P.¹; Rajive, K.¹; Al-Kandari, J.¹; Yaser, M.²; Mohamad-Hussein, A.²; Khaqan, K.²; Press, D.²; Xi, G.²; Lee, K.²; Chee, T.²
¹Kuwait Oil Company (KOC), Ahmadi, Kuwait.
²Schlumberger, Kuwait City, Kuwait.

The combined process of reservoir injection and depletion results in changes in effective stresses, which may cause formation deformation and thus dynamic change of permeability. A 3D reservoir geomechanics modeling was conducted for the Mauddud reservoir in Sabriya field situated in North Kuwait. A series of sensitivity analysis was carried out to examine the impact of permeability enhancement on well performance. The numerical results showed improvement of the reservoir production history match. 3D mud weight cube was then constructed. The impact of pore pressure change on fault stability was examined. Wellbore stability analysis was performed for a planned well. Hydraulic fracture simulations were conducted to evaluate the impact of water injection on the production of surrounding producer wells.

A representative pre-production stress state was obtained and was calibrated against measurements along the wells. Coupled reservoir geomechanics simulations were performed to improve the reservoir history matched model. Permeability updating due to intact rock pore volume change and due to induced plastic shear strain was simulated.

Results and Conclusions:

Water and oil productions and well pressure were examined at key well. The results showed improvements of predicted well pressure, and water and oil productions when compared with measured data. The overall field behavior showed improvement with respect to water cut, water production and oil production.

3D mud weight was used to establish the width of the stable mud weight window based on the difference between the breakout limit and the breakdown limit. The output provided guidelines on optimum wellbore direction for different formations and locations of the field.

Fault stability analysis of a fault intersected by a well showed that there was minimal potential drilling risk for the well.

Wellbore stability for the planned well showed minimum yielding at the wellbore wall for the proposed mud weight programme.

Hydraulic fracture simulations predicted fracture half length of 174 ft for Well A and 376 ft for Well B. The generation of fractures induced permeability enhancement which resulted in pressure gradient and consequently, an increase in water saturation around the wells.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012