抗高钙盐钻井液降滤失剂CARF-1合成及性能研究

Study on synthsis and properties of fluid loss reducer CARF-1 for high calcium salt drilling fluid

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)和甲基丙烯酸丁酯(BMA)为聚合单体,与一种纳微米无机矿物进行共聚,制备了钻井液用抗高温抗钙盐降滤失剂CARF-1。采用红外光谱、元素分析、热失重等方法分析了CARF-1的结构和热稳定性。室内性能评价结果表明,CARF-1在高钙盐钻井液和高矿化度复合盐水钻井液中经高温老化后均具有较好的降滤失能力;在含8%CaCl_(2)的膨润土浆中加量2.0%时API滤失量9.8mL,在高矿化度复合盐水钻井液中加量为2.5%时API滤失量9.6mL;与钻井液处理剂配伍性好,在高钙盐钻井液中加量为3.5%时,经150℃老化后API滤失量4.4mL、高温高压滤失量12mL。进一步通过Zeta电位测定和扫描电镜(SEM)分析,探讨了CARF-1在高钙盐下的抗钙盐降滤失机理。

A high calcium tolerant loss additive CARF-1 in drilling fluid was prepared through free radical polymerization initiated by a redox system,using a nano-micron inorganic mineral with acrylamide(AM)and 2-acrylamido-2-methylpropanesulfonic acid(AMPS)and alkenyl esters as monomers.Structure and thermo properties of the polymer CARF-1 were characterized by infrared spectroscopy(IR),elemental analysis and differential scanning calorimetry-thermogravimetric analysis(DSC-TG).Laboratory evolution experiment results indicated that CARF-1 has excellent filtrate loss reduction,in high calcium salt and high salinity compound brine mud.It was shown that under bentonite basic mud containing 8%CaCl_(2)and hot rolling 16 hrs at 150℃,basic mud with adding 2%CARF-1 could maintain the API fluid loss in 9.8mL,and that of basic mud without adding was 234mL;Moreover,under high salinity compound brine mud,with adding 2.5%CARF-1 could maintain the API fluid loss in9.6mL,and that of basic mud without adding was 171mL;The CARF-1 has good compatibility with drilling fluid additive.After hot rolling at 150℃,the drilling fluid containing 8%CaCl_(2)that added 3.5%CARF-1,the API fluid loss was 4.4mL and HTHP fluid loss was 12mL.The filtrate reducing mechanism under high concentration calcium in was revealed by Zeta potential measurement and SEM analyses.