钻井液用仿磺化沥青防塌剂的性能与作用机理

Performance Properties and Functioning Mechanisms of Pseudo Sulfonated Asphalt as Anticaving Agent for Water Base Drilling Fluids

本文报道的仿磺化沥青,为环氧乙烷、环氧丙烷共聚物在碱性条件下与一种天然大分子反应的产物,含磺酸物30%,油溶物40%,水溶物70%.在4%膨润土浆中加入2%仿磺化沥青或磺化沥青FT1(对比剂)制成实验浆液,用以测定封堵性和抑制性.将实验浆液加热至50℃,搅拌后测API滤失量(分别为26和19 mL)得到滤饼,通过水洗后的滤饼在0.7 MPa下测定4%CMC水溶液的滤失,前者略大于后者,30 min滤失量分别为8.9和8.0mL,表明仿磺化沥青的封堵性与磺化沥青相近,但受温度影响较大,在室温下较差.与磺化沥青相比,在仿磺化沥青浆液中,粘土压片前6 h的膨胀高度略大,在6～24 h略小,即仿磺化沥青与磺化沥青的抑制性相仿.二者防塌机理相近,不同处是:仿磺化沥青的水溶组分在浊点以上温度下从水溶液中析出,形成胶束粒子,产生封堵作用;其聚醚分子链通过氢键吸附,形成半渗透保护膜.仿磺化沥青无毒,2%悬浮液的EC50值大于1×104mg/L;不合生荧光基团,故无荧光.图2参13.

The pseudo sulfonated asphalt （PSA） presented in this paper is a reaction product of an EO/PO copolymer and a natural macromolecule in an alkaline medium and contains 30% sulfonic acid fraction, 40% oil soluble and 70% water soluble substances. The experimental mud （EM） is prepared by introducing 2 % sulfonated asphalt （SA）, FT1, as control chemical agent or PSA into 4% bentonite mud and used for evaluating sealing and inhibiting capacities. The EM heated to 50℃ and stirred is used for determining API filtrate loss （FL = 19 mL for SA EM and 26 mL for PSA EM） and the cake formed is water washed and used as filter to determine FL of 4 % CMC aqueous solution at 0.7 MPA, the FL is always slightly larger through PSA mud cake and the FL value in 30 min is 8.9 mL against 8.0 mL through SA mud cake. These results show that PSA and SA are similar in sealing property and the sealing property of PSA EM is more influenced by temperature and become weaker at room temperatures. The extent of swelling of bentonite in initial 6 hrs is slightly larger and very slightly smaller in 6--24 hrs of immersion in PSA EM than that in SA EM and therefore PSA and SA are similar in inhibiting capacity. The anficaving mechanisms of the two chemical agents are similar, too, with two distingusished differences originated from PSA： the water soluble substances in PSA can precipitate from the aqueous solution phase at temperatures higher than their cloud point to form micellar particles possessing sealing and filming abilities; the polyether chains in PSA can form protective semipermeable film by the way of hydrogen bonding. PSA is non-toxic with EC50 value 〉 1.0× 10^4 mg/L and is non-fluorescent because of absence of fluorescent functionalities.