Formula and preparation method suitable for preparing fracturing fluid from continental facies shale gas well fracturing flow-back fluid treatment water

Abstract

The invention discloses a formula and a preparation method suitable for preparing fracturing fluid from continental facies shale gas well fracturing flow-back fluid treatment water, belonging to the technical field of oilfield chemistry. The formula for preparing the fracturing fluid from the continental facies shale gas well fracturing flow-back fluid treatment water is provided aiming at the deficiencies existing in the prior art. The formula consists of base fluid and a cross-linking agent, wherein the cross-linking agent is an anti-temperature mineralization-degree-resistant cross-linking agent, and the formula comprises 0.4%-0.6% of cross-linking agent and the balance of base fluid; the base fluid consists of the following components in percentage by mass: 0.4%-0.45% percent of hydroxypropylguar gum, 0.3%-0.5% of gas well clean up additive, 1%-2% of stabilizer, 0.1%-0.15% of bactericide, 0.1%-0.2% of modifier, 0.03%-0.05% of antisludging agent, 0.6%-0.8% of gel breaker and the balance of the continental facies shale gas well fracturing flow-back fluid treatment water. The cyclic utilization of the continental facies shale gas well fracturing flow-back fluid treatment water is realized through the formula of the fracturing fluid, and the prepared fracturing fluid has good sand-carrying property.

Description

technical field [0001] The invention relates to a formula suitable for preparing fracturing fluid from treatment water for fracturing flowback fluid of continental shale gas wells, and belongs to the technical field of oil field chemistry. Background technique [0002] Shale gas reservoirs have extremely low porosity and matrix permeability, basically no natural productivity, and are deeply buried and have high formation pressure. Fracturing must be performed to achieve economical and effective development. Therefore, fracturing is the main technology for shale gas development. . Fracturing fluid is the working fluid for fracturing construction, which plays the role of transmitting pressure, breaking rocks, extending fractures and carrying proppants. After fracturing, 10-30% of the fracturing fluid flows back from the formation, which is called fracturing flowback fluid. Due to the tight reservoir and large volume of fracturing in shale gas well fracturing, the fracturing ...

AI Technical Summary

Problems solved by technology

The cations in continental shale gas fracturing flowback fluid are mainly calcium and magnesium ions, and the anions are mainly sulfate radicals, with a high degree of salinity. If the fracturing fluid is directly prepared, the following problems are found through experiments. First, the current The guar gum fracturing fluid formula that has been published and is being used in Yanchang Oilfield has the problem that the prepared fracturing fluid cannot be cross-linked or the viscosity is low after cross-linking due to its poor salinity resistance and high temperature resistance. In the experiment, the viscosity after shearing for 1 hour was below 50mPa.s, which could not meet the needs of medium-high temperature continental shale reservoir fracturing construction; secondly, there was scaling phenomenon in the direct preparation of fracturing fluid, and the residual content of fracturing fluid after gel breaking A large increase will cause the blockage of reservoir pores and sand-filled fractures, reducing the conductivity of shale gas

[0003] At present, the common practice is to simply treat a huge amount of fracturing flowback fluid and then discharge it directly. In the northern Shaanxi area where there is severe water shortage and fragile ecological environment, it will not only waste water resources, but also cause serious pollution to the water quality environment and soil.