Oilfield industrial wastewater recycling method

Abstract

The invention provides an oilfield industrial wastewater recycling method which comprises the following specific steps: step 1, a water injection station utilizes a nanofiltration water treatment device to remove sulfate ions from raw water to prepare clear water, the clear water is injected into an oil field water injection well through a water injection pump to achieve the purpose of water oil displacement, and concentrated water is recycled at a wastewater required position of a water treatment station; and step 2, the concentrated water obtained after nanofiltration water treatment is pulled to a profile control well site from the water injection station, the dosage of the concentrated water needing to be treated is determined, then two thirds of the concentrated water is added into aliquid preparation pool, and a salt-resistant polymer is added according to requirements in the concentrated water pumping process. concentrated water generated during oil field nanofiltration water treatment is effectively treated, the wastewater treatment cost is reduced, waste is recycled and turned into wealth, a profile control solution is prepared from salt-resistant polymers, auxiliaries and the concentrated water, and the profile control solution is injected into a stratum to form gel to block cracks and large pore channels, water shutoff profile control (profile control) is conductedon the oil reservoir, the deep liquid flow direction is changed, and the corresponding oil well dewatering and oil increasing effects are achieved.

Description

technical field [0001] The invention relates to the technical field of oilfield wastewater recycling and reuse, in particular to a method for recycling oilfield industrial wastewater. Background technique [0002] Water injection is the most common development method in my country's oilfields. By injecting water into the formation to maintain reservoir pressure and improve oil recovery. During the water injection process in Shanbei Oilfield, it was found that the injected water was not compatible with the formation water. At present, the oilfield uses nanofiltration membranes to remove sulfate ions in the injected water to reduce the scaling trend and achieve the purpose of preventing or delaying scaling. In the process of removing sulfate ions from the injected water, 15-20% of the wastewater with high concentration of sulfate ions is produced, except for a small part of the concentrated water that is reinjected into the reservoir with good compatibility, and the rest is in...

AI Technical Summary

Problems solved by technology

[0006] In order to overcome the problems that existing conventional polymers use concentrated water after oilfield water treatment to prepare profile control fluids that cannot be gelled and the plugging rate of rock cores is low, the present invention provides a method for recycling oilfield industrial wastewater. , salt-resistant polymers, other additives and cross-linking agents, the polymer profile control fluid is squeezed into formation fractures or high-permeability channels through pump trucks or plunger pumps, plugging reservoir fractures and high-permeability zones, and changing the depth of the formation. Fluid seepage direction, expand water flooding sweep coefficient, enhance oil recovery

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