A slippery water system with low adsorption damage

Abstract

The invention discloses a low-absorption-damage slick water system. The low-absorption-damage slick water system is prepared from the following components in percent by mass: 0.05-0.1% of resistance reducing agent, 0.1-0.5% of discharging aiding agent, 0.1-0.3% of desorbing agent and the balance of water, wherein the resistance reducing agent is linear polyacrylamide commonly-used in an oil field,and the weight-average molecular weight is 5-8 million; the discharging aiding agent is anion fluorocarbon surfactant; the desorbing agent is prepared from the following components in percent by mass: 8-15% of urea, 1-2% of SiO2 nanoparticle, 3-5% of cetyl sodium sulfate, 20-30% of ethylene glycol and the balance of water. The low-absorption-damage slick water system disclosed by the invention has the beneficial effects that the absorbing amount of the polyacrylamide in the slick water on the surface of shale rock can be obviously reduced, the yield-increasing effect after fracturing is improved; after the desorbing agent is added into the slick water system, the cost is increased by less than 10%, and the construction process is not changed, so that the market application prospect is wide.

Description

technical field [0001] The invention relates to a slick water system used for fracturing stimulation in the shale gas development process, in particular to a slick water system with low adsorption damage. Background technique [0002] Shale gas, as an efficient, clean and unconventional natural gas resource with great potential, has become a key energy source for development in my country. my country has a total of 54 shale gas exploration rights blocks, with an area of ​​about 17×10 4 km 2 . Shale gas reservoirs must be fractured to generate industrial gas flow. Shale fracturing needs to break the rock by injecting high-volume fluid, forming a large number of network fractures and carrying proppant with small particle size into the fractures. Slippery water with good drag-reducing performance is the first choice for large-volume construction . Slick water fracturing not only reduces the fracturing cost by 65% ​​compared with large-scale hydraulic fracturing in the same...

AI Technical Summary

Problems solved by technology

The temperature of my country's shale reservoirs is between 100-120 ° C. After entering the reservoir, these polyacrylamides with large molecular weight will not degrade at the formation temperature, but will be adsorbed on the shale rocks through the hydrophilic groups on the molecular chain. On the surface, clusters are finally formed to block the tiny pores of shale, seriously affecting the effect of fracturing

Therefore, an important means to improve the post-pressurization effect is to effectively reduce the adsorption of the drag reducing agent in the reservoir, but there is no corresponding countermeasure reported in the literature.