Relationship between the characteristic of irreducible water saturation and resistivity in low resistance limestone reservoir in A oilfield of Syria

The J formation in A oilfield of Syria is a rare low-resistance limestone reservoir in the world,the resistance of the oil reservoir is only 0. 5 ～ 5. 0 Ω. m,and its irreducible water saturation is higher than 70% . The origin of forming high irreducible water saturation in low-resistance limestone reservoir and the influence of the high irreducible water saturation on reservoir resistance are studied by numerical simulation of resistance. The results show that the reservoir resistance decreases with the increase of irreducible water saturation,which is consistent with the measured curves. This shows that the high irreducible water saturation is one of the main causes forming to the low-resistance limestone reservoir.