High-density low-friction fracturing fluid

Abstract

The invention relates to high-density low-friction fracturing fluid. The high-density low-friction fracturing fluid is made of, by weight, 20-46.5% of weighting agent sodium nitrate, 0.4-0.6% of thickener hydroxypropyl guar gum, 0.4-1.0% of cleanup additive Gemini surfactant, 0.1-0.3% of pH (potential of hydrogen) modifier, 0.1-0.3% of bactericide lauryltrimethylammonium chloride or dodecyl dimethyl benzyl ammonium bromide, 0.5-1.0% of clay stabilizer quaternary ammonium salt, 0.5-1.0% of temperature stabilizer organic amine composite, and the balance water. Sodium nitrate is used for increasing weight, the density at the normal temperature can reach 1.35g / cm<3>, and the high-density low-friction fracturing fluid is long in delayed crosslinking time, low in friction, low in filter loss, high in high-temperature rheological property, and especially applicable to fracture modification of ultradeep compact reservoirs under unusual high pressure, wellhead construction pressure can be reduced remarkably. Further, the high-density low-friction fracturing fluid is applicable to massive popularization and application to mine fields, low in cost and low in stratum damage, and has wide market prospect.

Description

technical field [0001] The invention relates to the technical field of reservoir transformation in petroleum engineering, in particular to fracturing fluid in hydraulic fracturing construction. Background technique [0002] Several abnormally high-pressure, ultra-deep and tight oil and gas reservoirs have been discovered in the central and western regions of my country. Such oil and gas resources require fracturing to obtain high yields. During high-pressure deep well reservoir fracturing operations, the required construction pressure often exceeds the pressure limit of the wellhead and pipe string, which cannot guarantee the safety of construction and the effect of measures, and even the construction operation cannot be carried out at all with the current technology and equipment. In order to solve this problem, a method of increasing the weight of the fluid column in the wellbore to reduce the wellhead pressure was proposed, thus resulting in a weighted fracturing fluid sy...

AI Technical Summary

Problems solved by technology

But for single potassium chloride weighting, the maximum density of the weighted fracturing fluid is 1.15g / cm 3 , the liquid column pressure provided is limited

At present, domestic laboratory experiments and mine field practice have proved that there are some major problems in the use of bromine salt aggravated formula: (1) The cost of bromine salt is high. Compared with ordinary fracturing fluid, the cost increased by about 2000-4500 yuan / m due to aggravation 3

Fracturing a well requires 500m of fracturing fluid according to the medium fracturing scale 3 , the cost will increase by 1.00-2.25 million yuan / well after aggravation; (2) For the guar gum system, the bromide weighting agent will prolong the crosslinking time, reduce the system fluidity index n value, and increase the consistency coefficient K value at the same time. Lead to increased flow friction; (3) Br - With reductive properties, the gel breaker is quickly consumed under high temperature and high pressure in the formation, making it difficult and incomplete for the fracturing fluid to break the gel, and the damage to the formation is increased

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