中东地区XT油田碳酸盐岩储层低阻成因机理研究

Analysis on Low-resistivity Origin of Carbonate Reservoirs in XT Oilfield of Middle East Area

中东地区XT油田碳酸盐岩储层的油层与水层的电阻率基本在1～3Ω.m左右,属于低阻碳酸盐岩储层。为了准确划分储层及识别流体性质,开展了碳酸盐岩储层低阻成因研究。通过铸体薄片、压汞、X-衍射、水分析资料和数值模拟研究,分析了泥质含量、束缚水饱和度、地层水矿化度、导电矿物对碳酸盐岩低电阻率的影响,得出在高地层水矿化度的前提下,泥质含量和导电矿物对电阻率降低的影响很小,高束缚水饱和度和高地层水矿化度是研究区碳酸盐岩储层低阻的主要原因。

The resistivity of oil and water of carbonate reservoirs in the XT Oilfield of Middle East area was basically in the range of 1~3Ω·m,it belonged to typical low resistance of carbonate reservoir.The genesis of low resistivity was studied to provide reliable basis of reservoir division and fluid properties distinguishing.By using casting thin sections,mercury-injection,X-ray diffraction and water analysis data,the effects of irreducible water saturation,formation water salinity,mud content and conductive mineral content on the low resistance of carbonate were analyzed.The results show that mud content and conductive mineral content have little effect on high formation water salinity.The high irreducible water saturation and high formation water salinity are the main reasons of inducing low resistance of carbonate reservoir.