储层温压变化与油藏地震监测

Variation of temperature and pressure in reservoir and seismic monitoring

在分析储层温压变化对孔隙流体地震特性、岩石孔隙度和速度等影响的基础上 ,以油藏注水地震监测为例说明了油藏地震监测中考虑温压变化的重要性 .研究结果表明 :①储层温度、压力的变化将会引起原油地震特性的明显变化 ,但地层水的变化相对较小 .②温度对岩石孔隙度和速度的影响是线性的 ,而压力的影响则是非线性的 .对于中等孔隙的砂岩 ,温度每增加 2 0℃ ,岩石的孔隙度和纵横波速度分别减小约 2 .6 %和 1.0 %以上 .对于深度在 110 0m左右的储层 ,4MPa的地层压力降低将分别会引起约 1.8%和 3.3%的纵、横波速度增加 .③在油藏强化开采地震监测研究中 ,除流体替换外 ,当储层温度、压力的变化较大时 ,其对实施油藏地震监测有具有非常重要的影响 ,必须慎重对待 .

Based on analysis of effects of temperature and pressure on seismic properties of pore fluid and porosity and velocity of sandstone. The importance of temperature and pressure in reservoir seismic monitoring is proved by the modeling analysis of water flooding seismic monitoring as an example. The research results show: ①The variation of temperature and pressure can cause clear changes of seismic properties of crude oil and less changes of reservoir water. ②Influences of temperature on porosity and velocity of sandstone are linear, but influences of pressure are nonlinear. Porosity and velocities of P and S waves in sandstone decrease about 2.6% and over 1.0% when temperature increases 20℃ in middle porosity sandstone. For the reservoir that depth is less than 1100m, the variation of reservoir pressure 4MPa can make the velocities of P and S waves increase about 1.8% and 3.3%. ③Besides fluid substitution, the larger changes of temperature and pressure sometimes are very important and must be treated cautiously in monitoring enhance oil recovery using seismic method.