三次采油用Gemini季铵型表面活性剂LTS的性能及应用

Performance Properties of Quaternary Ammonium Salt Gemini Surfactant LTS for Stimulating Injection Wells and Enhancing Oil Recovery

使碳数大于2的α,ω-二溴代烷与烷基二甲胺在无水乙醇中反应,得到了gemini季铵盐表面活性剂LTS,在45℃考察了LTS作为降压增注驱油剂的性能,配液用水为矿化度4902mg/L的大庆采油五厂模拟注入水。用电渗法测定,LTS溶液浓度由600mg/L增至800mg/L时,石英砂在LTS溶液中的表面zata电位由负变正。在石英砂上的饱和吸附量,LTS为0.082mg/L,石油磺酸盐ORS-41为0.102mg/L。LTS溶液浓度为500～600mg/L时,与大庆采油五厂原油间的界面张力降至10-3mN/m超低值。动态和静态接触角测定表明,100～800mg/L的LTS溶液可使亲油玻片表面变亲水,600mg/L的LTS溶液使亲水人造石英砂岩心表面变强亲水。Kg0.005～0.008μm2的人造砂岩岩心水驱之后用LTS溶液驱油,当LTS浓度由200mg/L增至1000mg/L时,注LTS压力相对于注水压力的降低率由26.74%增至42.85%,采收率增幅由5.80%增至14.96%。在大庆采油五厂平均渗透率0.01μm2的低渗透油层的6口井注入600mg/L的LTS溶液,单井日注量30～45m3,共注90天,此后平均注水压力下降0.9MPa,单井日增注8.5m3,对应油井年增产油1429t。

A quaternary ammonium salt gemini surfactant,LTS, was synthesized by reacting α,ω-alkylenebromide with carbon number 〉 2 and alkyldimethylamine in absolute ethyl alcohol and the performance properties of LTS as reservoir stimulating/flooding agent were investigated at 45℃ with working solutions prepared in a simulation injecting water with TSD = 4902 mg/L of the 5th Daqing Oil Production Factory（SDPF）. The zeta potential of quartz in LTS solutions changed from negative to positive when the LTS concentration increased from 500 to 600 mg/L. The saturated adsorption on quartz of LTS and ORS-41 ,a petroleum sulfonate for EOR,was of 0. 082 and 0. 102 mg/g, respectively. The interfacial tension between LTS solutions and 5 DPF crude oil was decreased down to uhralow values of 10^-3 mN/m magnititude when LTS concentration was of 500 and 600 mg/L. Dynamic and static contact angle measurements indicated that a treatment by 100--800 mg/L LTS solutions alternated the glass platelet surfaces from oleophilic to hydrophilic and a treatment by 600 mg/L LTS solution -- the surfaces of artificial sandstone cores from hydrophilic to strongly hydrophilic. In LTS surfactant flood experiments on artificial sandstone cores of Kg 0. 005--0. 008/μm^2 after water flood finished, the percent drop of LTS injecting pressure against water injecting pressure was increased from 26. 74% to 42. 85% and the enhancement in oil recovery was increased from 5.80% to 14.96% when the LTS concentration of the surfactant solution increased from 200 to 1000 mg/L. In a field trial conducted in an area of average permeability 0. 01/μm^2 of the 5DPF,30--45 m^3 of 600 mg/L LTS solution per well was injected into 6 water injection wells in 90 days and this resulted in a decrease in water injecting pressure by 0. 9 MPa,an increase in volume of water injected of 8.5 m^3/d per well, and a total additional oil output of 1429 t from the connected production wells in one year.