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Steam huff and puff oil extraction method for heterogeneous heavy oil reservoirs

A heavy oil reservoir, heterogeneous technology, applied in the fields of fluid production, earthwork drilling, data processing applications, etc., can solve the problems of high comprehensive water cut, poor thermal recovery production effect, low peak oil production, etc. The effect of steam sweep, improving production effect, and expanding the radius of action

Active Publication Date: 2020-04-17
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method uses an oil-soluble compound viscosity reducer and carbon dioxide as a viscosity-reducing slug before injecting steam. Although it can reduce the viscosity of crude oil, when it is applied in a heterogeneous reservoir, the steam injected next often preferentially enters the high-permeability, High-production intervals, and low-permeability and low-production intervals with high oil saturation are difficult to be effectively swept, resulting in poor production effect of heavy oil well huff and puff cycle thermal recovery, low cumulative oil production, and low peak oil production. High water content, low oil-gas ratio

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  • Steam huff and puff oil extraction method for heterogeneous heavy oil reservoirs

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Effect test

Embodiment 1

[0039] 1. Reservoir conditions

[0040] In a heavy oil development well, the middle depth of the reservoir is 315 meters, the effective thickness of the oil layer is 5.8 meters, the original oil saturation is 65.61%, the average porosity is 28.3%, and the average permeability is 1.28μm 2 , the permeability difference is 2.43, and the crude oil viscosity is 105177.6MPa.s at the reservoir temperature of 27.5°C, which belongs to the heterogeneous super heavy oil reservoir.

[0041] Conventional steam huff and puff has accumulated 12 rounds, the oil production in the 12th steam huff and puff cycle was 71.2t, the peak oil production was 1.3t, and the oil-steam ratio was 0.08.

[0042] 2. Steam huff and puff oil recovery

[0043] According to the reservoir conditions, the design volume is determined as: nitrogen foam 300m 3 (Amount of nitrogen foam converted according to formation conditions), emulsion viscosity reducer 8t, liquid carbon dioxide 100t, nitrogen 11000Nm 3 , Accumul...

Embodiment 2

[0055] 1. Reservoir conditions

[0056] The depth of a heavy oil reservoir is 299.4 meters, the effective thickness of the oil layer is 7.4 meters, the original oil saturation is 57.7%, the average porosity is 36.6%, and the average permeability is 2.43μm 2 , the permeability difference is 15.2, and the crude oil viscosity is 136447MPa.s at the reservoir temperature of 30.8°C, which belongs to super heavy oil and has the characteristics of low temperature and super heavy oil.

[0057] Conventional steam huff and puff has accumulated 3 rounds, the oil production in the third steam huff and puff cycle is 38t, the peak oil production is 2.1t, and the oil-steam ratio is 0.03.

[0058] 2. Steam huff and puff oil recovery

[0059] According to the reservoir conditions, the design volume is determined as: nitrogen foam 300m 3 (Amount of nitrogen foam converted according to formation conditions), emulsion viscosity reducer 6t, liquid carbon dioxide 86t, nitrogen 9300Nm 3 , A total ...

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Abstract

The invention relates to a steam huff and puff oil extraction method for heterogeneous heavy oil reservoirs, and belongs to the technical field of steam huff and puff oil extraction. The steam huff and puff oil extraction method for the heterogeneous heavy oil reservoirs comprises the steps that a nitrogen foam slug is injected into an oil layer; then a viscosity reducing slug is injected into theoil layer; then a nitrogen slug is injected into the oil layer; and steam is injected into the oil layer, and then well soaking and recovery are carried out. Nitrogen foam is firstly injected, effective plugging on a high-permeability high-production layer section can be achieved through the Jamin effect of the nitrogen foam, the subsequent slugs are promoted to enter a low-permeability low-production layer section high in oil saturation, and the aim of expanding steam sweeping is achieved. The viscosity of crude oil can be effectively reduced by the viscosity reducing slug. The nitrogen slugis beneficial to pushing the viscosity reducing slug to go deep into the oil layer, achieves the function of expanding the action radius of the viscosity reducing slug and further has the function ofimproving the flowback of a crude oil stratum in the production process, and the aim of increasing the single-well production per cycle and the recovery ratio of the heterogeneous heavy oil reservoirs is achieved through the cooperation of all the slugs.

Description

technical field [0001] The invention relates to a steam huff and puff oil recovery method for heterogeneous heavy oil reservoirs, and belongs to the technical field of steam huff and puff oil recovery. Background technique [0002] my country's heavy oil resources are widely distributed and rich in reserves, and account for a relatively high proportion of oil and gas resources. The high content of colloid, asphaltene and paraffin in heavy oil leads to high viscosity, poor fluidity, and difficulty in mining and gathering. The conventional production method of heavy oil reservoir is to inject high-temperature steam into the heavy oil reservoir, and use the heat carried by the steam to heat the heavy oil, thereby reducing the viscosity of crude oil and improving the fluidity of crude oil formation. Crude oil flows from the oil layer to the wellbore driven by the formation pressure, realizing the effective production of heavy oil reservoirs. [0003] Patent CN101255788A disclo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/24E21B43/16E21B43/22E21B47/00G06Q50/02
CPCE21B43/24E21B43/16E21B47/00E21B43/164G06Q50/02
Inventor 李飞鹏张喜玲余倩卢建恒王若浩王孟江赵长喜
Owner CHINA PETROLEUM & CHEM CORP