苦苈胶压裂液研究:冻胶性质

Gel Properties of Kuli Gum Fracturing Fluid

比较了苦苈胶、瓜尔胶压裂液的交联特性和黏弹性。苦苈胶可以作为油田水基压裂液的增稠剂,与硼砂和有机硼交联时,冻胶黏度随胶粉浓度的增加而增加;相同浓度下剪切30 min,苦苈胶冻胶黏度略高于瓜尔胶冻胶,耐剪切性较好。在能形成冻胶的pH值范围内,冻胶黏度随pH值的增加而增加;当pH值从8.78增至10.24时,苦苈胶冻胶黏度由85.46 mPa.s增至167.25 mPa.s。金属离子价态越高,对冻胶黏度的影响越大;金属离子浓度越高,冻胶黏度越小。离子浓度相同时,苦苈胶冻胶黏度高于瓜尔胶冻胶。当钙离子浓度从0增加到4 g/L时,苦苈胶冻胶黏度由400 mPa.s降至250 mPa.s,降幅达37.5%,特级瓜尔胶和二级瓜尔胶冻胶黏度分别降低45.8%和63.9%。加入三价铁离子,无法成胶。黏弹性测试结果表明,苦苈胶冻胶的储能模量和耗能模量均高于瓜尔胶冻胶,黏弹性较好。

Crosslinking properties and viscoelastic of kuli（vegetable-gum） and guar gum fracturing fluid were studied.Kuli gum could be used as a thickener in water-base-fracture fluid.The viscosity of kuli gel and guar gel increased with increasing concentration of powder when it reacted with crosslinkers.The viscosity of kuli gel was little higher than that of guar gel after 30 minutes sheering at the same concentration.The results showed that the kuli gum had a better anti-sheered property.At the gum crosslinking pH value,the viscosity of kuli gel and guar gel increased with increasing pH value.When the pH value increased from 8.78 to 10.24,the viscosity of kuli gel increased from 85.46 mPa·s to 167.25 mPa·s.The influence of metallic ion to the gel viscosity was marked with valence state.The viscosity of kuli gel and guar gel decreased with increasing concentration of metal cation.The viscosity of kuli gel was better than that of guar gel at the same metallic ion concentration.The viscosity of kuli gel decreased from 400 mPa·s to 250 mPa·s,and that of the extra grade guar gum gel and second grade guar gum gel decreased by 45.8% and 63.9% respectively with Ca2＋ concentration of 0—4 g/L.The gum could not crosslink when Fe3＋ was added.The results of viscosity test showed that G′ and G″ of kuli gel were higher than that of guar gel.The viscolastic property of kuli gum was better.