A preparation method of high-strength low-density fracturing proppant

Abstract

The invention discloses a preparation method of a high-strength ultra-low density fracturing proppant. Disperse the earthy graphite in ethanol solvent, add surfactant, heat and stir, cool, suction filter, and dry to obtain modified earthy graphite; add the modified earthy graphite to the solution containing the crosslinking agent and the initiator. In methyl methacrylate monomer solution; using water as dispersant, adding polyvinyl alcohol and suspending agent, synthesizing organic / inorganic composite microspheres by suspension polymerization, filtering, washing, drying, and passing through a 15-60 mesh sieve to obtain Fracturing proppant. The fracturing proppant prepared by the invention has a density of 1.053-1.133 g / cm 3 , close to water, and the crushing rate is only 8.5% under the pressure of 86MPa. In the process of use, water or salt water can be used as the sand-carrying fluid, which can greatly reduce the cost of fracturing construction, save energy and reduce emissions, avoid the use of guar gum and other polymer additives to carry fluid, and reduce environmental pollution.

Description

technical field [0001] The invention belongs to the technical field of fracturing and oil recovery, and in particular relates to a preparation method of a high-strength and ultra-low-density fracturing proppant. Background technique [0002] Hydraulic fracturing is the core technology of oil and shale gas exploitation, and one of its key materials is fracturing proppant. The fracturing proppant is brought into and supported by the fracturing fluid in the fractures of the fracturing formation, thereby effectively introducing oil and gas into oil and gas wells. Fracturing proppants are roughly divided into three categories: quartz sand, ceramsite proppant, and film-coated proppant. The film-coated proppant has two types: coated sand and coated ceramsite. Among them, quartz sand and coated sand are the current oil and gas It is the main proppant for shallow wells, while medium and deep wells need to use high-strength ceramsite proppant and film-coated proppant. [0003] An id...

AI Technical Summary

Problems solved by technology

The apparent density of ULW1.75 proppant is 1.75g / cm 3 It is a resin-coated porous ceramsite. The proppant has high sphericity, but poor compressive strength (40MPa), and the density is not low enough

The apparent density of ULW1.25 proppant is 1.25g / cm 3 , is a chemically modified walnut shell impregnated and coated with resin, which has low density and good compressive strength, but poor sphericity, which affects the conductivity, and the raw materials are limited

The apparent density of ULW1.05 proppant is 1.05g / cm 3 , is a thermosetting nanocomposite microsphere with low density and good sphericity, but expensive (65,000 yuan / ton), low compressive strength (40MPa), and poor temperature resistance (104°C)

Southwest Petroleum University in China has developed an ultra-low density fracturing proppant, which is a fired hollow glass microsphere with an apparent density of 1.5g / cm 3 ~2.0g / cm 3 , 60MPa broken rate < 10%, but its density is not low enough, the preparation process is complicated, and the cost is high

U.S. Patent US7568524B2 discloses a polyphenylene sulfide proppant (PPSProppant), which is a new type of organic proppant, which obtains polyphenylene sulfide microspheres by extrusion or molding, and the apparent density of the proppant is between 1.1 g / cm 3 ~2.0g / cm 3 The compressive strength is high, and the crushing rate is less than 5% at 52Mpa; however, this proppant has defects such as expensive preparation cost, low sphericity, and high requirements for equipment, so that this proppant cannot be popularized and applied

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