纳米二氧化硅复合早强剂的开发与性能评价

Development and performance evaluation of nano-SiO2 complex accelerator

侯献海 步玉环 郭胜来 罗勇 王雪英

HOU Xianhai BU Yuhuan GUO Shenglai LUO Yong WANG Xueying

中国石油大学华东石油工程学院 中海石油中国有限公司上海分公司 中原油田供水管理处

School of Petroleum Engineering, China University of Petroleum East China, Qingdao, Shandong 266580, China CNOOC China Shanghai Company, Shanghai 200030, China Water Supply Office of SINOPEC Zhongyuan Oilfield Company, Puyang, He’nan 457001, China

针对深水固井中油井水泥早期强度增长缓慢的问题，考察了纳米二氧化硅低温早强特性，并通过递进式叠加优化获得一种纳米二氧化硅复合早强剂NS-4。模拟深水固井的温度、压力条件，测试了该早强剂对油井水泥稠化性能、静胶凝强度和抗压强度的影响。研究结果表明：纳米二氧化硅复合早强剂组成方案为0.8% 纳米二氧化硅（质量分数，下同）+2% 硫酸钠+0.05% 三乙醇胺+0.2% 铝酸钠，掺量为水泥的3.05%；15 ℃、10 MPa 条件下掺入该早强剂的水泥浆稠化时间为236 min，其中稠化过渡时间为34 min；30 ℃、15 MPa 条件下静胶凝强度0~576 Pa 发展时间为180 min，其中胶凝过渡时间为48 min；在4 ℃、15 ℃、30 ℃下，加入该早强剂的水泥石24 h 抗压强度分别是纯G 水泥的9 倍、4.7 倍、2.4 倍。该早强剂优异的低温早强、防气窜性能，有助于解决深水固井面临的低温、浅层水/ 气流动的难题。

During deepwater cementing, early strength of oil well cement grows slowly. To solve this problem, the cryogenic early strength behavior of nano-SiO2 was investigated. By means of progressive superposition optimization, a nano-SiO2 complex accelerator NS-4 was obtained. The effects of this accelerator on the thickening performance, static gel strength and compressive strength were analyzed under simulated temperature and pressure conditions in deepwater cementing. The nano-SiO2 complex accelerator composed of 0.8% nano-SiO2 (mass fraction, the same below) + 2% sodium sulfate + 0.05% triethanolamine + 0.2% sodium aluminate is adopted,with its volume added being 3.05% of the cement volume. The test results show that, under the conditions of 15℃ and 10 MPa, the thickening time of cement slurry mixed with this accelerator is 236 min, including 34 min thickening transition time. Under the conditions of 30℃ and 15 MPa, the development time of 0-576 Pa static gel strength is 180 min, including 48 min gelling transition time. Under the conditions of 4℃, 15℃ and 30℃, the 24 h compressive strength of hardened cement mixed with this accelerator is 9 times, 4.7 times and 2.4 times the pure G cement respectively. The excellent cryogenic early strength and gas blocking performance of the accelerator contribute to solving such problems as low temperature and superficial water/gas flow confronted in deepwater cementing.

10.13639/j.odpt.2016.03.009