单井非常规乳化层有机组成与无机矿物分布

Organic composition and inorganic mineral distribution of unconventional emulsion layer in single well

以长庆油田采油十二厂Z240区块NH7-1单井乳化层为研究对象,采用红外光谱、热分析、核磁共振光谱、扫描电镜能谱等仪器分析方法,全面剖析了乳化层有机组分分布与无机矿物组成,探讨了单井非常规乳化层存在的主要原因。结果表明:乳化层质量含水率53.5%,标准密度909.8kg/m;、二甲苯可溶有机组分含量43.0%,渣含量3.5%;有机组成主要为原油,胶质、沥青质含量比例较高,约10.05%~14.01%;无机组分以地层水中的氯化钠、氯化钙为主,附以少量石英、硫酸钡、碳酸钙等;乳化层还包括极少量的化学药剂,主要成分为短直链、含硝基或含氮类化学药剂。非常规乳化层存在的主要原因为压裂返排药剂与矿物颗粒分散于原油乳状液中,加之胶质、沥青质含量较高,使乳化层异常稳定,难以破乳。

Taking the emulsion layer of NH7-1 well in Z240 block of No.12 oil production plant of Changqing Oilfield as research object, the distribution of organic components and the composition of inorganic minerals of emulsion layer are comprehensively analyzed by means of infrared spectrum, thermal analysis, nuclear magnetic resonance spectrum, energy spectrum of scanning electron microscope. The main reasons for the existence of unconventional emulsion layer in single well are discussed. The results show that the mass moisture content of emulsion layer is 53.5%, the standard density is 909.8 kg/cm3, the content of Xylene soluble organic component is 43.0%, slag content is 3.5%. Organic component is mainly crude oil, and the content of glial asphaltene is high while the proportion range is 10.05%—14.01%. The inorganic components are mainly sodium chloride and calcium chloride in formation water, with a small amount of quartz, barium sulfate, calcium carbonate, etc. The emulsion layer also includes a very small amount of chemicals, mainly short chain, nitro or nitrogen-containing chemicals. The main reason for the existence of unconventional emulsion layer is that fracturing flowback agent and proppant are dispersed in crude oil emulsion, and the content of gum and asphaltene is high, which makes the emulsion layer extremely stable and difficult to demulsify.