Method for in-situ production of solvent in oil layer to exploit thickened oil

An oil layer, in-situ technology, applied in the fields of fluid production, earthwork drilling, wellbore/well components, etc., can solve the problems of uneconomical, high operation cost of solvent injection and heavy oil production, and high solvent cost, and achieve the effect of reducing the impact

Active Publication Date: 2021-02-05
SOUTHWEST PETROLEUM UNIV
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  • Description
  • Claims
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AI Technical Summary

Problems solved by technology

[0005] Although the efficiency of solvent-assisted steam injection in heavy oil recovery is high, the cost of solvent is high, and the recovery rate of solven

Method used

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  • Method for in-situ production of solvent in oil layer to exploit thickened oil
  • Method for in-situ production of solvent in oil layer to exploit thickened oil
  • Method for in-situ production of solvent in oil layer to exploit thickened oil

Examples

Experimental program
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Effect test

Example Embodiment

[0057]Example 1 (such asFigure 4 ,Figure 5 Shown)

[0058]An ultra-heavy oil reservoir adopts the SAGD production method of vertical well gas injection and horizontal well oil production. The horizontal section of the horizontal well is 400 meters in length and the operating pressure of the steam chamber is 4.0 MPa. After several years of continuous steam injection, a larger steam cavity volume was formed in the reservoir, and the crude oil recovery rate exceeded 45%. As SAGD enters the middle and late stages of development, the heat loss ratio of injected steam in the steam cavity increases, the oil-steam ratio decreases, and the oil drain rate decreases. In order to make full use of the waste heat in the steam chamber and reduce the steam consumption per unit of oil produced, it was decided to greatly reduce or stop steam injection on the ground. Laboratory studies and numerical simulation studies have shown that solvent-assisted SAGD is the best way to improve the mining effect in t...

Example Embodiment

[0060]Example 2 (such asImage 6 Shown)

[0061]The viscosity of the crude oil in this reservoir is 5000-10000 mPa.s at reservoir temperature, the thickness of the pure oil layer is 5-10 meters, the depth of the oil layer is 2000 meters, and the oil layer pressure is 20 MPa. The crude oil in this reservoir has a certain flow ability at the temperature of the reservoir, but the cold production yield is low. Due to the limitation of the depth and thickness of the oil layer, the thermal recovery efficiency of surface steam injection is low, and it is difficult to obtain an economic oil-steam ratio.

[0062]Drill a horizontal well with a length of 400-600 meters in the oil layer. It is located at the bottom of the oil layer. The horizontal section is completed with a screen (such asImage 6 Shown). First, all downhole pipe strings and electric heating devices (200-300 kW), power supply cables and downhole temperature monitoring required for in-situ production of solvents in the oil layer to ext...

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Abstract

The invention relates to a method for the in-situ production of solvent in an oil layer to exploit thickened oil. The method includes the steps that crude oil in the oil layer near a shaft is heated to a target temperature by using an electric heating device, a chemical reaction assistant is injected into a heating section to achieve the reaction condition of high-temperature hydrothermal crackingof the crude oil, light oil components and gas generated move upwards to a vapor cavity under the action of heating power and gravity, and the light oil and part of gas transferred to a vapor-liquidinterface are dissolved into the crude oil to reduce the viscosity of the crude oil and increase the yield of the crude oil; non-condensed gas left in the vapor cavity is used for expanding and supplementing energy for the vapor cavity, so that the heat loss of the vapor cavity to a top cover layer is reduced; and the crude oil discharged to a cracking reaction section is heated and then continuesto be cracked, and the crude oil discharged to a production section enters into a screen pipe and then is lifted to the ground through an underground pump. According to the method for the in-situ production of the solvent in the oil layer to exploit the thickened oil, the solvent is generated in the oil layer in situ to achieve solvent-assisted thickened oil recovery, so that the heat utilizationrate is increased, the CO2 emission is reduced, the final recovery ratio is increased, and the method has wide market application prospects.

Description

technical field [0001] The invention belongs to the field of oil field development, and relates to a heavy oil recovery method, in particular to a method for producing heavy oil with in-situ solvent generation in an oil layer. Background technique [0002] China's heavy oil resources exceed 200×10 8 t, more than 70 oilfields distributed in 12 sedimentary basins, the producing geological reserves put into commercial development are about 14×10 8 t. Since the crude oil viscosity of most heavy oil reservoirs in China is higher than 10,000mPa.s, steam injection thermal extraction is the main method. Steam huffing and puffing is still the main method of heavy oil production in China, but most oilfields have entered the final stage of production, the efficiency of steam is low, and the ultimate recovery rate is generally less than 30%. The recovery factor of steam flooding and SAGD technology is relatively high (higher than 50%), but it is only applicable to reservoirs with goo...

Claims

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Application Information

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IPC IPC(8): E21B43/24E21B43/241E21B36/04E21B43/38E21B43/22
CPCE21B43/24E21B43/241E21B36/04E21B43/38E21B43/16E21B43/2408E21B43/121E21B47/06
Inventor 蒋琪刘佳丽吴芳杰黄思源于春生周翔王志彬
Owner SOUTHWEST PETROLEUM UNIV
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