用硼中子寿命测井确定低渗透砂岩储层剩余油饱和度

Calculating Remaining Oil Saturation of Sandstone Reservoir With low Permeability Using BoriteNeutron Lifetime Log

硼中子寿命测井是向地层中注入高俘获截面的硼酸，从而使中子寿命测井也适用于低矿化度地区。对于低孔低渗储层，由于束缚水和残余油的含量很高，可动流体所占比例已很少，允许的误差范围也小，在定量求取剩余油饱和度时，具有不同于高孔高渗储层的新特点。文中结合二连油田地质特征，推导分析了低渗透砂岩储层的剩余油饱和度方程。最后用这一方程处理了二连油田一口水淹井的硼中子寿命测井数据，并作了详细分析。

Neutron lifetime logging (NLL) is generally used in cased hole for determining remaining oil saturation of formation with high salinity. Due to injection of boric acid with large neutron capture cross section, NLL is also adaptable to formation with low salinity. For formation with low porosity and low permeability, the saturations of irreducible water and remaining oil are high, and that of movable fluid is very low.Thus the way of calculating remaining oil saturation for formation with low porosity and low permeability is different from that for formation with high porosity and high permeability and has its own characteristics. Combined with the geological features of Erlian oilfield, the equation of remaining oil saturation for sandstone reservoir with low permeability is given herein. The BNLL data from one waterflooded well in Erlian oilfield is processed with the above equation. The analysis result shows that the geological effect is very good.