Synthesis method and application of "befc tracer"

Abstract

The invention relates to a synthetic method and application of a BEFC tracer. Rare-earth element tracing method is one of effective measures to detect oil reservoirs in oilfields. A NaBiF4:Eu3+@C4H4Na2O6 fluorescent nano material with core-shell structure is synthesized herein and may act as an oilfield tracer, named as BEFC tracer. The tracer herein has the advantages of good water solubility, low usage, low water sample demand, good analytical simplicity, high analytical sensitivity, zero radiation, low toxicity, every low environmental impact, zero impact on mineralization degree, good compatibility with polymers, and zero impact on polymer flooding. The application of the BEFC tracer as one fluorescent nano material in the field of oilfield detection is innovatively achieved herein; afeasible operating scheme is provided as well.

Description

technical field [0001] The invention relates to a europium ion-doped bismuth sodium fluoride@sodium tartrate nanomaterial with a core-shell structure, which is especially suitable as an oil field interwell tracer. It has good fluorescence and can detect oil reservoirs and test the distribution and movement of oil reservoir fluids . Background technique [0002] In the water injection development of complex fault-block oilfields, due to the heterogeneity of the oil layer itself, high permeability zones or large pores will gradually form between oil and water wells, the efficiency of water flooding will decrease, the water cut of oil wells will rise sharply, and the development effect will obviously deteriorate. The tracer can qualitatively judge the existence of high permeability zones or large pores, and the interwell tracer is an important means to detect the distribution and movement of reservoir fluids and the heterogeneity of reservoirs. There are following problems in ...

AI Technical Summary

Problems solved by technology

[0003] First, there are few types of tracers that can be widely used in oil fields at present, which is due to the many limitations of the nature of the tracer itself and the types and physical and chemical properties of the formation minerals

[0004] Second, commonly used tracers are anions, dyes, low-molecular alcohols, etc. that are easy to detect. Such tracers use a large amount (up to several tons), are highly toxic, require a large amount of water samples, and have low analytical sensitivity. Shortcomings such as long measurement cycle are not conducive to environmental friendliness

[0005] Its three, the use of ammonium thiocyanate, sodium bromide, potassium iodide also can make salinity increase, has influenced the viscosity of polymer solution, because the influence of polymer, the error that sodium bromide, potassium iodide detects is bigger, and potassium iodide The high cost makes the use of both limited

[0006] Fourth, artificial radioactive substances—— 60 Co. 3 H. 82 Br, etc., due to the high difficulty of detection, it is not easy to realize on-site detection, and its use is limited; with the improvement of environmental protection requirements, this substance will also be gradually eliminated

[0007] Fifth, the titration method is currently the most commonly used method for determining the content of rare earth elements. However, this method has many steps. After repeated extractions, the error of the separation operation is relatively large, and the measurement cycle is long; at the same time, the error caused by human differences is also relatively large. , under the condition that the analysis conditions remain unchanged, increasing the concentration of rare earth elements is one of the effective solutions to improve the analysis accuracy, but the increase of the concentration of rare earth elements leads to the increase of its use cost, so in the actual application of oil field detection of oil reservoirs , in order to control the cost, rare earth tracers are not commonly used

[0008] Sixth, the previous fluorescent tracers used a large amount, the cost was high, and their chemical and physical properties were unstable in the formation. Inorganic fluorescent materials are very easy to adsorb on the sediment and other small molecules or small particles in the underground oil layer. Above; organic fluorescent materials have poor chemical stability in complex underground environments, and are easy to react with other substances, causing tracer failure

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