초록 ▼

The improved recovery of hydrocarbons from subterranean formations by fracturing and matrix acidizing a subterranean formation is accomplished. Well treatment fluids having a viscoelastic surfactant fluid containing worm like micelles are useful to improve recovery of hydrocarbons and limit the loss

The improved recovery of hydrocarbons from subterranean formations by fracturing and matrix acidizing a subterranean formation is accomplished. Well treatment fluids having a viscoelastic surfactant fluid containing worm like micelles are useful to improve recovery of hydrocarbons and limit the loss of fracturing fluid into the formation fracture face. The viscolastic surfactant-based fracturing fluids of the present Invention are stable across a wide pH spectrum, allowing them to be used for fracturing treatments at low pH, as well as matrix acidizing treatments. In addition, the stability of these fluids is enhanced in the presence of organic anions. Two-stage fracturing treatments comprised of a viscoelastic surfactant-based fracturing fluid and a polymer-based system, wherein the two fluids are either blended or pumped into the formation sequentially (the polymer last) are also presented.

대표청구항 ▼

[ What is claimed is:] [1.]1. A method for fracturing comprising injecting into a subterranean formation a fluid consisting essentially of:an aqueous medium prepared at least substantially from seawater;a quaternary ammonium salt having four R groups, R.sub.1, R.sub.2, R.sub.3, and R.sub.4, each bon

[ What is claimed is:] [1.]1. A method for fracturing comprising injecting into a subterranean formation a fluid consisting essentially of:an aqueous medium prepared at least substantially from seawater;a quaternary ammonium salt having four R groups, R.sub.1, R.sub.2, R.sub.3, and R.sub.4, each bonded to a common nitrogen, wherein R.sub.1, R.sub.2, R.sub.3, and R.sub.4, are each the same or different, and are either --H or an aliphatic moiety having at least about 16 carbon atoms, which may be either branched or straight, and further which may be either saturated or unsaturated, and further wherein R.sub.2 and R.sub.3 may be each or both substituted with a functional group that imparts greater hydrophilicity to said ammonium salt;a substantially water-soluble salt comprising a cation selected from the group consisting of alkali metal, alkaline earth metal, aluminum, zirconium, Zn.sup.2+, NH.sub.4.sup.+, and (CH.sub.3).sub.4 N.sup.+ and an anion selected from the group consisting of sulfate, nitrate, perchlorate and halide; andan organic stabilizer, said stabilizer in turn comprising a first functionality consisting of a member selected from the group consisting of an hydroxyl group and a carboxylate group, and a second functionality selected from the group consisting of a electron-donating functionality, and further wherein said first and second functionality are both attached to a ring structure, or separated by at least one double or triple bond.