钻井液用超高温抗盐聚合物降滤失剂的研制与评价

针对当前国内外超高温水基钻井液高温稳定性及滤失性调控技术难题,基于分子结构优化设计、聚合单体优选,通过优化合成条件研制了抗高温(240℃)抗盐聚合物降滤失剂HTP-1。HTP-1的最优合成条件为:pH=7.0、单体配比DEAM∶AMPS∶NVP∶DMDACC=6∶3∶3∶1、引发剂0.1%、反应温度60℃、反应时间4 h。热重分析表明,HTP-1的热稳定性很强,发生热分解的初始温度达320℃以上。HTP-1的抗盐能力大于267 g/L,抗钙能力大于5 g/L,与国外抗温聚合物Driscal相当,优于国内钻井液用金属离子增黏降滤失剂PMHA-Ⅱ。HTP-1在淡水基浆、淡水加重基浆、饱和盐水基浆和复合盐水基浆中均具有优异的抗高温(240℃)降滤失作用,优于国外Driscal(抗240℃)和国内PMHA-Ⅱ(抗220℃)。分析了HTP-1的抗温、抗盐抗钙和降滤失作用机理。图6表5参5

Development and Evaluation of Anti Ultra-high Temperature and Salt Tolerant Polymeric Filtrate Loss Reducer

Aimed at the outstanding problem of adjustment of filtration property and high temperature stability of high temperature water-based drilling fluid at home and abroad,the anti 240 ℃ and salt tolerant polymeric filtrate loss reducer HTP-1 was developed based on optimum design of molecular structure and selection of monomer.The optimum synthesis conditions of HTP-1 was as follows: pH value was 7.0,the mass ratio of DEAM,AMPS,NVP,DMDACC was 6∶ 3∶ 3∶ 1,the initiator content was 0.1%,reaction temperature was 60℃ and reaction time was 4 h.the result of thermal gravitational analysis showed that the thermal decomposition onset temperature of HTP-1 was up to 320℃,indicating that HTP-1 possessed strong thermal stability.The experiments of calcium and salt tolerance showed that performance of HTP-1 in drilling fluid containing 267 g/L salt or 5 g/L calcium chloride was stable,which was similar to that of the foreign anti high temperature polymer Driscal and superior to domestic metallic ion fluid loss additive PMHA-Ⅱ.The filtration reducing ability of HTP-1 at high temperature of 240℃ was better than that of Driscal(240℃) and domestic PMHA-Ⅱ(220℃) in fresh water drilling fluid,weighted fresh water drilling fluid,saturated brine drilling fluid and compound salt water drilling fluid,respectively.In the end,the mechanisms of heat and salinity tolerance and filtrate loss reduction of HTP-1 were probed.