| 摘要: |
| 采用前置液有效驱替油基钻井液是提高页岩气井固井质量的关键,表面活性剂则是决定前置液驱替效果的关键。目前,单纯以清洗效率为指标考虑工程性能来优选表面活性剂,工作量大且有一定的盲目性。因此,开展了基于表面活性剂特性的优选方法研究:①确定了清洗效率较高的表面活性剂离子类型和HLB值范围；②确定润湿渗透柴油基钻井液表面所需的临界表面张力γc；③从表面活性剂表面张力和临界胶束浓度(CMC值)进行优选；④将材料研究与工程模拟评价相结合,最终确定一套适用于柴油基钻井液的前置液表面活性剂优选方法。实验结果表明,适用于柴油基钻井液的前置液用表面活性剂应满足以下特性:①应选用非离子或阴离子表面活性剂,且HLB值应在12~15；②表面活性剂的较优加量应接近或大于表面活性剂的临界胶束浓度；③表面活性剂的γlg(溶液表面张力)应小于或接近润湿柴油基钻井液表面的γc(临界表面张力为25~27 mN/m),此时,前置液的清洗效率较高。该方法可为表面活性剂的优选提供指导,有助于提高页岩气井固井质量。 |
| 关键词: 页岩气 水平井 柴油基钻井液 表面活性剂 临界表面张力 清洗效率 优选方法 |
| DOI：10.3969/j.issn.1007-3426.2015.03.016 |
| 分类号:TE254+.4 |
| 基金项目:国家973项目课题“页岩气水平井钻完井关键基础研究”(2013CB228003)。 |
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| Optimization of preflush surfactant in diesel fuel base drilling fluid |
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Ou Hongjuan1,2, Li Ming1,2, Gu Tao1,2, Liu Honghua2, Yang Yan3, Guo Xiaoyang2
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(1. School of Material Science and Engineering, Southwest Petroleum University, Chengdu 610500, China;2. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China;3. Drilling＆Production Technology Research Institute, PetroChina Jidong Oilfield Company, Tangshan 063000, China)
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| Abstract: |
| Preflush effective displacing oil-base drilling fluid is the key to improve the cement quality of shale gas, and surfactant is the key to decide the displacing effective of preflush. Currently, optimizing surfactant only by cleaning efficiency as index to consider engineering performance is a heavy workload and has certain blindness. Therefore, researches of optimization method depending on surfactant properties were carried out. Firstly, the ion type and HLB value extent of surfactants with context higher cleaning efficiency were determined. Secondly, the critical surface tension γc required by surface of wetting and penetrating diesel fuel based drilling fluid were ensured. Thirdly, the surfactants were optimized by combining surface tension of surfactant with CMC values. Fourthly, combining the material research with engineering evaluation, a set of optimization method suitable for preflush surfactants of diesel fuel base drilling fluid was determined. Experimental results showed that preflush surfactants of diesel fuel base drilling fluid should meet the following characteristics:①non-ionic/anionic surfactants should be used, and the HLB value should be 12~15; ②optimum dosages of the surfactant should be close to or over the critical micelle concentration of the surfactant; ③the surface tension γlg of surfactant should be less than or close to the soaking surfaces of oil-based drilling fluid γc(the critical surface tension=25~27 mN/m), and the cleaning efficiency of preflush is higher. This method can provide guidance for optimization of surfactants, and help to improve the cementing quality of shale gas well. |
| Key words: shale gas horizontal wells diesel fuel base drilling fluids surfactant critical surface tension cleaning efficiency optimization method |
