A three-phase foam composite flooding system and its application

A composite flooding and system technology, which is applied in the direction of production fluid, drilling composition, wellbore/well components, etc., can solve the problems of single gas and limited application, so as to reduce the oil-water mobility ratio, improve the sweep coefficient, The effect of foam stabilization

CN103980873BActive Publication Date: 2016-11-09CHINA UNIV OF GEOSCIENCES (BEIJING)
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2016-11-09

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Abstract

The invention relates to a three-phase foam complex oil flooding system and application thereof. The three-phase foam complex oil flooding system consists of a foaming agent, a foam stabilizer, water and gas, wherein the foaming agent and the foam stabilizer are uniformly dispersed into the water to form an oil flooding system solution; the proportion of components is as follows: the foam stabilizer is 0.1-0.3% in percentage by mass, and the foaming agent is 0.1-0.4% in percentage by mass; the gas is nitrogen, carbon dioxide or natural gas; the volume ratio between the oil flooding system solution and the gas is 1:(1-1.5), and the oil flooding system solution and the gas are alternately injected into the stratum or rock cores. The three-phase foam complex oil flooding system disclosed by the invention can be used for reducing the liquid discharge speed of a liquid membrane, increasing the viscoelasticity and strength of the liquid membrane, and ensuring that the foam is more stable, has good oil flooding effects, and can be used for enhancing the oil recovery.
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Description

technical field

[0001] The invention relates to foam flooding that can be used to enhance oil recovery, in particular to a three-phase foam composite oil flooding system, belonging to the technical field of enhanced oil recovery and oilfield chemistry. Background technique

[0002] With the rapid growth of my country's national economy, the demand for oil continues to increase. With the current mining technology, more than 50% of oil demand depends on imports, which will cause my country to face major economic and national energy security issues. Tertiary oil recovery technology is currently the main means to greatly increase oil recovery, and related technologies are developing rapidly in my country, including polymer flooding, binary (surfactant / polymer) composite flooding and triple (surfactant / alkali) flooding. / polymer) composite flooding can increase oil recovery by more than 10%, more than 15% and more than 20% respectively on the basis of water flooding. However, so...

Examples

Embodiment 1

[0049] Example 1: Three-phase foam composite oil displacement system, which is composed of oil displacement system solution and nitrogen at a volume ratio of 1:1, which are injected into formations or cores alternately in sequence.

[0050] Oil displacement system solution: foaming agent is tetradecyl hydroxysulfobetaine surfactant (THSB), and the percentage of foaming agent accounting for total oil displacement system solution mass is 0.2%; Foam stabilizer is made of nonionic polyacrylamide It is composed of phenolic resin jelly dispersion 1:1, wherein the molecular weight of non-ionic polyacrylamide is 6 million, the degree of hydrolysis is 2%, the size of the jelly dispersion is 50-60 μm, and the foam stabilizer accounts for the mass percentage of the total oil displacement system solution 0.2%; the rest is water.

[0051] The above oil displacement system solution is abbreviated as: 0.2%THSB+0.1%NPAM+0.1%DPG+residual water, the same expression is also used in the following...

Embodiment 2

[0059] As described in Example 1, the difference is: the length × width × height of the basic parameters of the three-layer heterogeneous core = 30cm×4.5cm×4.5cm, and the permeability of the high, middle and low layers is 5 μm, 2 μm, 0.5 μm. Oil flooding results: the water flooding recovery rate is 43.6%, the ultimate recovery rate after three-phase foam composite flooding reaches 89.6%, and the enhanced oil recovery rate is 46.0%.

Embodiment 3

[0061] As described in Example 1, the difference is: the injection slug is the first 0.15PV oil displacement system solution, followed by alternate injection of 0.15PV nitrogen gas (2 times); the oil displacement result: the water flooding recovery rate is 37.0%, three-phase After foam composite flooding, the ultimate recovery rate reaches 70.1%, and the enhanced oil recovery rate reaches 33.1%.