The present invention provides aqueous viscoelastic compositions comprising a cleavable surfactant and possibly also an electrolyte. The cleavable surfactants useful in the present invention comprise at least one weak chemical bond, which is capable of being broken under appropriate conditions, to produce oil soluble and water soluble products typically having no interfacial properties and surface activity compared with the original surfactant molecule. Further, the rheological properties of the aqueous viscolelastic composition are usually altered upon cleavage of the cleavable surfactant generally resulting in the elimination of the viscofying, viscoelastic and surfactant properties of the composition. Aqueous viscoelastic compositions in accordance with the present invention are suitable for use in oil-field applications, particularly for hydraulic fracturing of subterranean formations. Thus, the present invention also relates to a wellbore service fluid and a method of fracturing a subterranean formation. The present invention also concerns novel cleavable surfactants.
本发明提供了包含可裂解表面活性剂和可能还包含电解质的
水性粘弹性组合物。本发明中有用的可裂解表面活性剂包括至少一种弱
化学键,它能够在适当条件下被断裂,产生油溶性和
水溶性产物,通常与原始表面活性剂分子相比没有界面性和表面活性。此外,
水性粘弹性组合物的流变性质通常在可裂解表面活性剂解离后发生改变,通常导致组合物的粘性、粘弹性和表面活性特性的消失。根据本发明的
水性粘弹性组合物适用于油田应用,特别是用于地下地层的
水力压裂。因此,本发明还涉及井眼服务液和压裂地下地层的方法。本发明还涉及新颖的可裂解表面活性剂。