基于易降解型双子氟碳表面活性剂的新型助排剂研究

Research on a new type of cleanup additive based on degradable gemini fluorocarbon surfactant

关键词:  易降解  双子  氟碳表面活性剂  助排剂

Key words:  easily degradable  gimini  fluorocarbon surfactant  cleanup additive

摘要:

目前,在油田常规压裂酸化助排剂中,氟碳表面活性剂普遍含有全氟辛基羧酸及其盐类(PFOA)、全氟辛基磺酸及其盐类(PFOS),其氟碳链比较长,存在降解困难、持久性生物累积等问题。从氟碳原料的选择入手,选用生物降解性好的短氟碳链原料作为氟碳表面活性剂的合成原料,进行分子设计、结构优化,研制了一种双子氟碳表面活性剂,进而开发出高效、环境友好的压裂、酸化用含氟碳类表面活性剂的助排剂体系产品。该双子氟碳表面活性剂表面活性强,临界胶束摩尔浓度低至3.0×10-4～3.4×10-4 mol/L,γ_cmc=16.0 mN/m,新型助排剂助排效果优异,其助排率分别达到57.1%与63.6%,并在ST-8井的胶凝酸酸化施工与H-201井加砂压裂施工中成功应用。

Abstract:

At present, among the conventional fracturing and acidizing in oil fields, using them as cleanup additives:fluorocarbon surfactants generally contain perfluorooctyl carboxylic acid and its salts (PFOA), perfluorooctyl sulfonic acid and its salts (PFOS). The fluorocarbon chain of them is relatively long, facing the problem of difficult degradation and persistent bioaccumulation. In this paper, starting from the selection of fluorocarbon raw materials, the biodegradable short fluorocarbon chain raw materials were selected as the synthetic materials of fluorocarbon surfactants. Through optimizing the molecular design and structure, the system products containing fluorocarbon surfactants with high-efficiency, environment-friendly fracturing and acidizing on site were screened and developed. The results showed that the gimini short-fluorocarbon surfactant has strong surface activity, and the critical micelle concentration is as low as 3.0×10-4-3.4×10-4 mol/L and γ_cmc=16.0 mN/m. The new type of cleanup additive has excellent effect, and the rate of cleanup is 57.1% and 63.6% respectively. It has been successfully applied in the construction of cementitious acid acidification in ST-8 well and the construction of sand fracturing in H-201 well.