CO2吞吐对储层结垢趋势的影响研究

在采用CO2吞吐采油过程中,由于CO2的注入,对储层可能造成结垢伤害。室内实验表明:在地层高压条件下,产生CaCO3垢的可能性较小,在温度有明显升高的部位可能形成CaCO3垢;随着水中溶解的CO2减少,pH值升高,CaCO3结垢的趋势增大;高矿化度油田水能促进CaCO3溶解,可抑制CaCO3垢的生成;CaCO3优先于MgCO3,CaSO4成垢。用东辛地层水试验表明,CO2的注入对其三口井岩心的渗透率影响不大。

Study on lnfeation of Fouling of Oil Deposit Caused by CO2 Injection

In the oil production, the injection of CO2 may lead to the fouling of oil deposits. The laboratory tests demonstrate that there is very little possibility of the formation of CaCO3 at high pressure condition of the deposits. The CaCO3 fouling may be formed in the high temperature locations. With the decrease of dissolved CO2 in the water, increase of pH, the tendency of CaCO3 fouling is becoming greater. In addition, the highly mineralized water will promote the dissolution of CaCO3, which is favorable for the inhibition of formation of CaCO3. CaCO3 will more easily form the fouls than MgCO3 and CaSO4.The test using Dongxin underground water shows that the injection of CO2 has little impact on the premeation rate of rock core of three oil wells.