抗高温抗高钙降滤失剂DF-1的研制与评价

Synthesis and Evaluation of High Temperature Resistant and High Calcium Tolerant Filtrate Loss Additive DF-1

为解决高钙污染下水基钻井液的稳定性及滤失性难调控问题,利用2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、二甲基二烯丙基氯化铵(DMDAAC)和丙烯酰胺(AM)单体合成了抗高温抗高钙降滤失剂DF-1。最佳合成条件为:AMPS、DMDAAC、AM质量比4.1∶2.9∶3.0,引发剂过硫酸铵加量0.3%,p H值=7,反应温度40℃,反应时间3h。室内评价结果表明,150℃老化16 h及40000 mg/L Ca2+污染下,添加DF-1基浆体系的表观黏度为9 m Pa·s,滤失量为16 m L,而未老化空白基浆的值分别为7.5 m Pa·s和30 m L,基浆体系的流变性和滤失性基本不受影响。采用红外光谱(IR)、TGA热重分析、滤饼扫描电镜(SEM)以及元素能谱(EDS)分析DF-1的微观作用机理。DF-1分子结构中含—CONH2和阳离子胺基,有助于其通过氢键和静电吸附在黏土表面有效吸附。分子链段热稳定性好,在300℃开始分解。Ca2+污染后,添加DF-1前后滤饼中Ca2+的相对含量分别为15.96%和3.77%;DF-1能有效阻止Ca2+在黏土表面离子交换吸附,从而阻止黏土颗粒聚并,有效形成致密滤饼。

In order to overcome the difficulty in maintaining the instability of drilling fluids after high calcium contamination,a high temperature resistant and high calcium tolerant fluid loss agent DF-1 was synthesized using 2-acrylamide-2-methyl propane sulfonic acid(AMPS),acrylamide(AM) and diallyl dimethyl ammonium chloride(DMDAAC) monomers. The optimum synthesis condition was obtained as follows: 4.1∶2.9∶3.0 the monomer mass ratio of AMPS∶DMDAAC∶AM,0.3% initiator ammonium persulfate,7 p H value,40℃ reaction temperature and 3 hrs reaction time. Laboratory evolution experiment results showed that under 40000 mg/L Ca Cl2 contamination and hot rolling 16 hrs at 150℃,basic mud with adding DF-1 could maintain the apparent viscosity in 9 m Pa·s and the API fluid loss in 16 m L;and that of basic mud without aging was 7.5 m Pa·s and 30 m L,respectively. The mechanism of DF-1 was revealed by IR、TGA、SEM and EDS analyses. The IR analysis result showed that the polymer contained —CONH2and quaternary ammonium group,which could help it to strongly absorb on bentonite by hydrogen and ionic bonds. TGA analysis result showed that DF-1 had excellent thermal stability within 300℃. EDS and SEM analysis results indicated that the relative calcium ratio of mud API cake in calcium contamination could reduce from 15.96% to 3.77% after adding DF-1,which attested that DF-1 was able to effectively decrease the ion exchange absorption of calcium on bentonite,thereby could prevent the bentonite particles from being coagulation and form a dense cake.