油基钻井液中沥青软化点变化规律及其降滤失机理分析  

Analysis of softening point variation pattern of bitumen in oil-based drilling fluid and its filtration loss reduction mechanism

作　　者：王昌军[1] 倪天姿 吴宇 罗觉生[1] WANG Changjun;NI Tianzi;WU Yu;LUO Juesheng(College of Chemistry and Environmental Engineering,Yangtze University,Jingzhou 434023,Hubei;Jingzhou Jiahua Technology Co.,Ltd.,Jingzhou 434000,Hubei)

机构地区：[1]长江大学化学与环境工程学院,湖北荆州434023 [2]荆州嘉华科技有限公司,湖北荆州434000

出　　处：《长江大学学报（自然科学版）》2023年第2期77-83,共7页Journal of Yangtze University(Natural Science Edition)

基　　金：国家自然科学基金联合基金项目“复杂碳酸盐岩储层转向酸与固体转向剂协同转向机理研究”(U1762107)。

摘　　要：天然沥青在柴油中部分溶解会降低其软化点及固相有效含量,也必然会降低其在油基钻井液中的封堵降滤失作用效果。为解决这一问题,研究选择合适性能的天然沥青尤为重要。实验研究了4种不同软化点的天然沥青。油溶率测定评价了天然沥青的油溶性;四组分分析、红外光谱分析、薄层色谱分析研究了天然沥青油溶前后的组成;高温高压滤失/PPT封堵测试评价了油基钻井液中天然沥青的封堵降滤失效果;软化点测定研究了天然沥青泥饼掺油软化粘结特性。结果表面:高软化点天然沥青在柴油中的油溶率为20.0%,其饱和分和芳香分含量低、胶质和沥青质含量高;油基钻井液中,天然沥青在低于本身软化点20~30℃的页岩地层中使用,封堵滤失效果好。天然沥青掺油后不溶物和高温软化粘结在页岩地层孔隙及微裂缝中起主要封堵降滤失作用,可为天然沥青在油基钻井液中优选性能指标提供参考。Partial dissolution of natural bitumen in diesel fuel will reduce its softening point and effective solid phase content,and will inevitably reduce its effectiveness in sealing and filtration loss reduction in oil-based drilling fluids.In order to solve this problem,it is particularly important to study the selection of natural bitumen with suitable properties.In this paper,four types of natural bitumen with different softening points were experimentally studied.The oil solubility of natural bitumen was evaluated by oil solubility determination;the composition of natural bitumen before and after oil solubility was studied by four-component analysis,infrared spectroscopy and thin-layer chromatography analysis;the HTHP filtration loss/PPT plugging test was used to evaluate the plugging and filtration loss reduction effect of natural bitumen in oil-based drilling fluids;the softening point determination was used to study the softening and bonding characteristics of natural bitumen mud cake mixed with oil.The results show that the oil solubility rate of natural asphalt with high softening point in diesel oil is 20.0%,its saturate and aromatic content is low,while its gum and asphaltene content is high.In oil-based drilling fluids,natural bitumen is used in shale formations at 20~30℃lower than its softening point,and has a good effect on plugging filter loss.The insoluble matter and high-temperature softening bonding of natural asphalt mixed with oil play a major role in sealing and reducing filtration loss in the pores and microfractures of shale formations,which can provide a reference for the preferred performance index of natural asphalt in oil-based drilling fluids.

关 键 词：天然沥青 油基钻井液 软化点 降滤失 油溶率 粒径分布 

分 类 号：TE254[石油与天然气工程—油气井工程]