Method for developing deep-layer heavy crude reservoir by carbon dioxide auxiliary steam driving

A technology of carbon dioxide and auxiliary steam, which is applied in the direction of production fluid, earthwork drilling, wellbore/well components, etc., and can solve the problems of dryness difficult to meet steam drive requirements, low recovery factor, low oil-steam ratio, etc.

Active Publication Date: 2008-03-12
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Overcome the problem of low production period and long production period of existing steam flooding
Solve the problem that the dryness of traditional single steam injection in deep heavy oil reservoirs cannot meet the requirements of steam flooding, resulting in low oil-steam ratio and low recovery

Method used

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  • Method for developing deep-layer heavy crude reservoir by carbon dioxide auxiliary steam driving
  • Method for developing deep-layer heavy crude reservoir by carbon dioxide auxiliary steam driving
  • Method for developing deep-layer heavy crude reservoir by carbon dioxide auxiliary steam driving

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Experimental program
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Effect test

Embodiment 1

[0036] Embodiment 1: refer to accompanying drawing 3. The method for developing deep heavy oil reservoirs by carbon dioxide assisted steam flooding of the present invention has been tested in an oil field. This oilfield is suitable for the development of combined steam flooding of vertical wells and horizontal wells assisted by carbon dioxide injection after high rounds of steam huff and puff in deep heavy oil reservoirs. After long-term steam stimulation, the pressure has dropped below 3MPa, and the remaining oil is mainly distributed in the interwell area, which is suitable for the steam flooding development method of replenishing energy to the formation. Therefore, if an infill horizontal well is drilled between wells with abundant remaining oil, first huff and puff for 2 to 3 cycles, and after thermal communication with the vertical well is established, it can be transferred to the vertical well to inject carbon dioxide and steam. .

[0037] The specific method is:

[0...

Embodiment 2

[0054] The buried depth of an oilfield reservoir is 1300m, the effective thickness of the oil layer is 30.0m, the net total thickness ratio of the oil layer is 0.65, the average porosity is 22.0%, the average permeability is 1000md, the coefficient of variation of permeability is 0.60, and the viscosity of crude oil under the oil layer conditions is 400- 500cp. The oil field has been developed by steam stimulation for 15 years, the formation water content is relatively high, the recovery degree of the steam stimulation stage is 20.0%, and the formation pressure is 4-5 MPa. Carbon dioxide assisted steam flooding was used to develop deep heavy oil reservoirs in this oilfield.

[0055] A. Selecting reservoirs suitable for CO2 assisted steam flooding

[0056] According to the geological characteristics and development status of the oilfield, rough screening of the oilfield is carried out. Reservoirs suitable for carbon dioxide-assisted steam flooding meet the following condition...

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Abstract

A method to excavate deep heavy oil reservoir with carbon dioxide auxiliary steam drives adapts to oil field exploitation. The method is characterized in that: Exploitate deep heavy oil reservoir with a composite rod drive for straight wells and horizontal wells. Meanwhile, the invention is designed to fill carbon dioxide gas at the same time of filling steam. The specific value of of underground volume in cold water valent weight between the carbon dioxide and steam is 8 to 10; total injection volume of the carbon dioxide is 0.2 to 0.5PV. The targets are as follows: Solve the problem that, the traditional method of only injecting steam into deep heavy oil reservoirs is difficult to meet steam drive requirements, so that oil-steam ratio and percent recovery are both too low. After meeting cold oil at the early stage of transcending condensed water, the carbon dioxide can solve some raw oil, lower viscosity, improve raw oil fluidity, shorten low-yield period in the preliminary stage of the steam drive, and improve oil recovery speed. On the basis of steam throughput, the method can improve yield extent by about 30 percent, and accumulated oil-steam ratio can be higher than 0.20; taking yield extent during the throughput stage into considerations, total percent recovery can reach about 50 percent.

Description

technical field [0001] The invention relates to the technical field of oilfield exploitation, in particular to a method for exploiting heavy oil by high-pressure steam flooding. It is a method of using carbon dioxide assisted steam flooding to increase the recovery rate and oil recovery rate of heavy oil reservoirs after oilfield steam huff and puff. Background technique [0002] In the oil recovery process of heavy oil reservoirs, the steam flooding oil recovery technology used is the successor technology of steam huff and puff oil recovery. As shown in Figure 1, it is a conventional vertical well steam flooding reverse nine-point well pattern. Conventional steam flooding adopts a well pattern consisting of vertical wells and vertical wells. The steam injection well 1 in the center continuously injects steam into the well, and the adjacent production wells 2 around it continuously produce crude oil. Theoretical research and field practice at home and abroad show that the ...

Claims

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Application Information

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IPC IPC(8): E21B43/24
Inventor 高永荣闫存章刘尚奇沈德煌郭二鹏
Owner PETROCHINA CO LTD
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