压裂返排液水质特性评价及回用技术研究

为了明确压裂返排液中影响回用的突出污染物,从而针对性地研究现场处理技术,采用水质矩阵法对苏里格气田常用的两种体系压裂返排液的水质特性进行评价。结果表明:影响胍胶压裂返排液回用的污染物重要程度排序为钙镁离子、铁离子、悬浮物和pH值;影响可回收体系压裂返排液回用的污染物重要程度排序为悬浮物、pH值、钙镁离子和铁离子,两者差异明显。以此为基础,针对胍胶压裂返排液,提出“化学絮凝、离子控制、金属网过滤”的现场处理工艺,钙镁离子降低了83.7%,铁离子降低了79.6%,悬浮物降低了85.0%;针对可回收体系压裂返排液,提出“重力沉降、金属网过滤”的现场处理工艺,悬浮物降低了81.0%,处理后水质达到重复配液要求。

Study on Water Quality Characteristic Evaluation and Reuse Technology of Fracturing Back-flow Fluids

In order to clarify the key pollutants affecting the reuse of fracturing back-flow fluids,and to study the field treatment technology pertinently,the water quality characteristics of fracturing back-flow fluids of two systems commonly used in Sulige Gas Field were evaluated by water quality matrix method.The results shown that the importance of pollutants affecting the reuse of guanidine gum fracturing back-flow fluids are ranked as calcium and magnesium ions,iron ions,suspended solids and pH value;the importance of pollutants affecting the reuse of fracturing back-flow fluids in recoverable system are ranked as suspended solids,pH value,calcium and magnesium ions and iron ions,the difference between them is obvious.Based on the above evaluation results,a field treatment process of chemical flocculation,ion control and metal mesh filtration was proposed for guar gum fracturing back-flow fluids.The calcium and magnesium ions decreased by 83.7%,iron ions decreased by 79.6%and suspended solids decreased by 85.0%.In view of the fracturing back-flow fluids of recoverable system,a field treatment process of gravity sedimentation and metal mesh filtration was proposed.The content of suspended solids was decreased by 81.0%,and the treated water quality met the requirement of repeated liquid distribution.