Nano magnetofluid fracturing fluid imbibition oil-increasing method for tight reservoir and modified nano magnetic particles

A nano-magnetic fluid, tight reservoir technology, applied in the fields of fluid production, chemical instruments and methods, earth-moving drilling, etc., can solve the problems of damage to the reservoir, inconvenience, and high cost, so as to increase crude oil production and reduce water production. The effect of improving the diversion capacity

Active Publication Date: 2019-11-15
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The implementation steps of this process are cumbersome, which is not conducive to on-site operation, and the application field is limited for extra-heavy oil and super-heavy oil reservoirs, which is very inconvenient in practical application
And the used base fluid of this nano-magnetic fluid is kerosene or other hydrocarbons, which has potential safety hazards. The nano-particle volume content of the used nano-magnetic fluid is 30%, and the consumption is very large, and the cost is very high
[0005] At present, polymer-based slickwater fracturing fluid system is mainly used in the stimulation of tight reservoirs, which has the advantages of low cost, low friction, and strong fracturing ability. Staying in the rock pores has the potential to damage the reservoir, and affects the rock's imbibition of fracturing fluid, reducing the effect of imbibition and oil displacement in tight reservoirs
[0006] Therefore, based on the advantages of nano-magnetic fluid, construct a nano-magnetic fluid flooding fracturing fluid with low adsorption, low surface tension and low friction, which can not only significantly reduce the liquid-solid interfacial tension, but also absorb nanoparticles into the reservoir. It can selectively adsorb crude oil droplets in the pores, and the migration direction is controlled by the external field. It is expected to realize the organic combination of intelligent nanomaterials and fracturing stimulation technology, and greatly improve the oil recovery of tight oil reservoirs. After searching, there is no Reports in related literature

Method used

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  • Nano magnetofluid fracturing fluid imbibition oil-increasing method for tight reservoir and modified nano magnetic particles
  • Nano magnetofluid fracturing fluid imbibition oil-increasing method for tight reservoir and modified nano magnetic particles
  • Nano magnetofluid fracturing fluid imbibition oil-increasing method for tight reservoir and modified nano magnetic particles

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0056] Modified nano-magnetic particles, which are surface-modified nano-Fe 3 o 4 Granules, the surface modifier is sodium oleate. The particle size range is 60nm~70nm, the temperature resistance range is less than or equal to 225°C, and the molar magnetic susceptibility is 480~510cm 3 / mol.

[0057] Preparation of modified magnetic nanoparticles (such as figure 1 shown):

[0058] a. At a stirring speed of 500r / min, mix NaOH and NH with a molar ratio of 1:1 3 ·H 2 O mixed solution was slowly added to 100 mL of FeCl with a solubility of 0.5 mol / L 2 In the solution, adjust to pH = 10, and continue to stir for 30 minutes to complete the reaction.

[0059] b. Add 3.05g sodium oleate (C 17 h 33 CO 2 Na), then continue to stir for 60min, making C 17 h 33 COO- fully adsorbs on Fe 3 o 4 surface.

[0060] c. After stopping the stirring, let it stand still and use a strong magnet to separate Fe 3 o 4 particles, and then alternately washed with distilled water and absolu...

Embodiment 2

[0067] The preparation of the modified nano-magnetic particles is the same as in Example 1.

[0068] The method for imbibing and increasing oil by nano-magnetic fluid fracturing fluid in tight reservoirs includes the following steps:

[0069] (1) Add modified nano-magnetic particles into the fracturing fluid base fluid and mix evenly to obtain a magnetic fracturing pre-fluid. The mass ratio of the fracturing fluid base fluid to the modified nano-magnetic particles is 6:4; The magnetic fracturing pre-fluid is injected to form fractures in the formation, the width of the fractures is 0.1-1.5cm, and the length of the single wing of the fracture is 10-200m;

[0070] (2) Connect a plurality of coil-wrapped electromagnets at the tail of the downhole tubing. The electromagnets are connected to the ground power supply through cables, and the magnetic field of the electromagnets is controlled by applying current through the ground power supply. The power supply is applied so that the m...

experiment example

[0074] Experimental verification of strong lipophilic and hydrophobic properties of modified nano-magnetic particles:

[0075] Apply the modified nanoparticles on the surface of the quartz plate and flatten it, then drop water and crude oil on the surface, and test the contact angle between water and modified nanoparticles and the contact angle between crude oil and modified nanoparticles through a contact angle meter Angle, to verify that the modified nano-magnetic particles have strong lipophilic and hydrophobic properties, the results are as follows image 3 shown by image 3 It can be seen that the contact angle between water and modified nanoparticles is 105.36°, which has strong hydrophobicity, and the contact angle between crude oil and modified nanoparticles is 31.83°, which has strong lipophilicity.

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Abstract

The invention relates to a nano magnetofluid fracturing fluid imbibition oil-increasing method for a tight reservoir and modified nano magnetic particles. The nano magnetofluid fracturing fluid imbibition oil-increasing method comprises the steps that magnetic fracturing prepad fluid is pumped into a formation, a crack is formed in the formation, a magnetic field is applied to the well bottom, andthe modified nano magnetic particles in the magnetic fracturing prepad fluid are delivered to a target oil reservoir; a fracturing fluid base fluid and a propping agent for fracturing are mixed to form sand-carrying fluid to be pumped into the crack formed in the formation, so as to support the geometrical shape of the crack; and after fracturing construction, the magnetic field is applied to thewell bottom, thus the nano magnetic particles adsorbing crude oil flow back into a wellbore and then recovered out of the ground, and the magnetic particles are recovered through the magnetic force effect. The nano magnetofluid fracturing fluid imbibition oil-increasing method for the tight reservoir and the modified nano magnetic particles are suitable for an oilfield with the high water content, the modified nano magnetic particles have high lipophilicity and hydrophobicity, thus the magnetic particles adsorb the crude oil in the target oil reservoir and flow back to the wellbore through the pressure difference at the well bottom and the effect of the externally applied magnetic field, the crude oil output can be well increased, water production is reduced, the magnetic nanoparticles are recovered out of the ground in the oil recovery process, and the magnetic particles can be recovered through magnetic force to be reused, so that the production cost is reduced.

Description

technical field [0001] The invention relates to a method for imbibing and increasing oil by nano-magnetic fluid fracturing fluid in tight reservoirs and modified nano-magnetic particles, belonging to the technical field of petroleum exploitation and the field of material preparation. Background technique [0002] At present, the average recovery rate of oilfields in the world is about 35%. In the process of oilfield development, especially unconventional oil reservoirs such as ultra-low permeability oil and gas reservoirs and tight oil and gas account for an increasing proportion. How to further increase the recovery rate has become a Issues that need to be considered. At present, the EOR methods generally adopted by domestic and foreign technologies mainly include water flooding, air flooding, CO 2 Flooding, gas-water alternate flooding, chemical flooding, and thermal recovery, etc. Although EOR technology has now formed a relatively complete and rich system, there are st...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/267C09K8/68C09K8/60C09K8/90C09K8/84C09K8/66
CPCE21B43/267C09K8/68C09K8/605C09K8/602C09K8/90C09K8/845C09K8/665
Inventor 罗明良巩锦程杨宗梅罗帅李钦朋战永平其他发明人请求不公开姓名
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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