抗高温改性淀粉降滤失剂的制备与性能

针对改性淀粉降滤失剂抗温能力不足的问题，从提高分子刚性的角度出发，以丙烯酰胺（AM）、2-丙烯酰胺基-2-甲基丙磺酸（AMPS）、二甲基二烯丙基氯化铵（DMDAAC）、N-乙烯基吡咯烷酮（NVP）、2，5-二羟基苯磺酸钾（PDHBS）为单体，辣根过氧化物酶（HRP）为催化剂，采用酶促反应方法，合成出一种改性淀粉降滤失剂St-AANDP，基于相同反应条件合成未含苯环结构的对比改性淀粉降滤失剂St-AAND。对降滤失性能进行测试，结果表明，140℃下老化16.0 h后，加量为1.0%的St-AANDP钻井液的常温中压滤失量仅为5.2 mL，高温高压滤失量为26.2 mL ；当老化温度高于160℃时，St-AANDP钻井液的滤失量才出现明显增大，抗盐可达饱和，降滤失性能明显优于St-AAND钻井液。通过吸附量和泥饼微观形貌测试，揭示了可通过向分子主链中引入苯环提高分子刚性的方式来提高降滤失剂抗温能力的作用机理。 

Preparation and Performance of a High Temperature Modified Starch Filter Loss Reducer

A new modified starch, St-AANDP, has been developed to address the deficiency of high temperature resistance of modified starch presently in use. Aimed at enhancing the rigidity of the molecules, the new modified starch was synthesized with the following chemicals through enzyme catalysis reaction:acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), dimethyl diallyl ammonium chloride (DMDAAC), N-vinyl pyrrolidone (NVP), potassium 2,5-dihydroxy benzenesulfonate (PDHBS) as the monomers, and horseradish peroxide (HRP) as the catalyst. A reference modified starch with no benzene ring, St-AAND, was also synthesized at the same reaction conditions. Test on the filtration control performance of the two synthesized modified starches showed that a drilling fluid sample treated with 1.0% St-AANDP had API filter loss of only 5.2 mL and HTHP filter loss of 26.2 mL after aging 16 h at 140℃. The filtration rate of St-AANDP treated drilling fluids increased only when the aging temperature was increased to above 160℃. St-AANDP works normally in salt saturated drilling fluids, and has filtration control performance that is superior to St-AAND. The reason for st-AANDP to have better filtration control performance than St-AAND is, based on the measurement of adsorption capacity and on the observation of the micromorphology of mud cakes, the introduction of benzene rings into the backbone of the starch molecules.