大庆油区三元复合驱矿场结垢状况分析

Analysis on field scaling of ASP flooding in Daqing Oilfield

通过对大庆油区不同井距、不同碱型三元复合驱采出液中Ca2+和Mg2+及碱浓度变化的分析,研究了结垢对三元复合驱的影响。结果表明,Ca2+和Mg2+浓度变化趋势与采出液碱浓度的变化趋势具有较强的相关性,即随着三元复合驱油体系前缘到达井口,Ca2+和Mg2+浓度大幅度减少,甚至消失,说明油层中出现结垢现象;强碱三元复合驱结垢严重,弱碱三元复合驱结垢较轻;井距越大结垢越严重。在三元复合驱推广应用时,应选用弱碱,井距不宜过大,并尽量采用螺杆泵。

The influence of scaling on ASP flooding was investigated after analyzing the concentration change of the Ca2+ ,Mg2+and the alkali in the produced liquid of ASP flooding with different alkali and well spacing. The results show that the trend of the concentration of Ca 2+ and Mg 2+ is well relevant to the trend of the concentration of the alkali in the produced liquid. When the leading edge of ASP system reaches to the wellhead,the concentration of Ca2+ and Mg2+ decreases sharply and sometimes they can not be detected,which indicates that the scale has been produced in the reservoir. The scaling of ASP flooding with strong alkali is more serious than the ASP flooding with weak alkali; the longer the well spacing is,the more serious the scaling is. In the popularization of the ASP flooding, the weaker alkali should be chose, the well spacing should not be too large and the screw pump should be used in the oil well.