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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  • Abstract
  • Description
  • Claims
  • Application Information

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 solvent injected into the formation is usually low (less than 70%), which makes the operation cost of solvent injection in heavy oil recovery high, even uneconomical

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

Embodiment 1

[0057] Example 1 (eg Figure 4 , Figure 5 shown)

[0058] A super-heavy oil reservoir adopts the SAGD production mode of vertical well gas injection and horizontal well production. The horizontal section of the horizontal well is 400 meters long and the operating pressure of the steam chamber is 4.0 MPa. After several years of continuous production with steam injection, a large volume of steam cavity has been formed in the reservoir, and the recovery degree of crude oil exceeds 45%. As SAGD enters the mid-to-late production stage, the heat loss ratio of steam injected into the steam cavity increases, the oil-steam ratio decreases, and the oil drainage rate decreases. In order to make full use of the waste heat in the steam chamber and reduce the steam consumption per unit oil production, it was decided to significantly 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 i...

Embodiment 2

[0060] Example 2 (eg Figure 6 shown)

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

[0062] Drill a horizontal well with a horizontal section length of 400-600 meters in the oil layer, which is located at the bottom of the oil layer, and the horizontal section is completed with a screen (such as Figure 6 shown). All the downhole tubing strings and electrical heaters (200-300 kW), power cables and downhole temperature monitoring required for in situ generation of solvent reco...

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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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