压裂液伤害性研究

文章对油田使用的3种压裂液（羟丙基瓜胶、聚合物及表面活性剂）产生的二次地层伤害进行评定，通过吸附实验、固体残渣测定及岩心流动实验，定量和定性地说明了３种压裂液对地层的伤害。结果表明：增稠剂CTAB和聚合物KTU在４种吸附剂上的吸附量大小顺序为蒙脱土＞高岭土＞岩心砂＞石英砂，而阳离子表面活性剂在高岭土和蒙脱土上的吸附量均高于KTU；清洁压裂液对地层的伤害最小，损害率为12.5%， 聚合物压裂液次之，为35%，而瓜胶压裂液伤害最大达到43.7% ；瓜胶压裂液破胶后在地层的残余量最大，为333.3 mg/Ｌ，清洁压裂液和聚合物压裂液几乎没有残渣。通过膨胀性测试可以看出，清洁压裂液的粘土防膨性能最佳，粘土膨胀率仅有5.7%；聚合物压裂液次之，为9.47%；瓜胶压裂液最差，为43.54%。

A STUDY OF FORMATION DAMAGE OF FRACTURING FLUID

Secondary formation damages caused by 3 fracturing fluids commonly used in oilfields, including hydroxypropylguar gum, polymer and surfactant, are quantitatively and qualitatively evaluated through adsorption experiment, solid residue measurement and core flow test. The adsorbances of the thickener CTAB and polymer KTU on 4 kinds of adsorbents are in the following sequence, from large to small, polynite>kaolin>core sand>quartz sand, while both the adsorbances of cationics on kaolin and polynite are larger than that of KTU. The formation damage of clean fracturing fluid is the smallest, with a damage rate of 12.5%, followed by polymer fracturing fluid with a damage rate of 35%, while guar gum is the largest, with a damage rate up to 43.7%. The amount of residue of guar gum fracturing fluid in formations after gelout is the highest at 333.3 mg/L, while clean fracturing fluid and polymer leave almost no residues. Expandability experiments show that the clay swelling rate of clean fracturing fluid is the lowest, being at 5.7%, followed by polymer fracturing fluid, being at 9.47%, while that of guar gum is the highest, being at 43.54%.