共聚物PAAND作钻井液降滤失剂的合成及应用评价

Synthesis and Performance Evaluation of the Copolymer-PAAND Used as Fluid Loss Additive in Drilling Fluid

摘要:

以丙烯酰氧乙基三甲基氯化铵（DAC）、乙烯基吡咯烷酮（NVP）、丙烯酰胺（AM）和2-丙烯酰胺基-2-甲基丙磺酸（AMPS）为单体，(NH4)2S2O8-NaHSO3为引发剂，采用自由基水溶液聚合的方式合成了一种四元共聚物作为钻井液用降滤失剂。通过正交实验确定了具有最佳降滤失效果的合成条件，采用红外光谱法对共聚物的结构进行了表征。性能评价结果表明，合成的共聚物具有良好的耐温抗盐和降滤失性能，聚合物质量分数为1.5%时，淡水、盐水、饱和盐水以及复合盐水基浆的API滤失量(0.7 MPa, 30 min)分别为5.6 mL，9.7 mL，19.0 mL和16.1 mL。与新疆油田常用的SP-8，JT888，MAN104和HJ-3四种降失水剂相比，合成的聚合物表现出了更好的降滤失性能。现场适用评价表明，该降滤失剂与新疆油田莫北91井区的钾钙基聚磺钻井完井液体系、滴西12井区的正电胶钻井液完井液体系以及石南4井区SN2XXX井的聚磺钻井完井液体系都具有良好的现场适用性。

Abstract:

The copolymer, which was used as fluid loss additive for drilling fluid was synthesized by free radical polymerization in aqueous solution, using N-Vinyl-2-pyrrolidon (NVP), Dimethyl- aminoethyl acrylate methylchloride (DAC), 2-Acrylamide-2-methylpropanesulfonic acid (AMPS) and acrylamide (AM) as monomers, ammonium persulfate and sodium sulfite as initiators. The synthetic conditions with optimal property were achieved by the orthogonal experiment, and the structure of copolymer was characterized by FT-IR. The results of performance evaluation showed that the synthesized copolymer had excellent temperature resistance, good heat resistance as well as salt tolerance. When the mass fraction of copolymer was 1.5%, the API filtrate volume (0.7 MPa, 30 min) of fresh water drilling fluid, saline water drilling fluid, saturated-brine drilling fluid and composite-brine drilling fluid were 5.6 mL，9.7 mL，19.0 mL and 16.1 mL. Compared with frequently-used fluid loss additives of SP-8，JT888，MAN104 and HJ-3 in Xijiang oil field, the synthesized copolymer showed the better property in controlling the fluid loss of drilling fluid system. The evaluation of field application demonstrated that the fluid loss additive had good site suitability with potassium calcium based sulphonated polymer drilling and completion fluid system, MMH drilling and completion fluid system, and sulphonated polymer drilling and completion fluid system in Xinjiang oil-field.