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Composite foam flooding method suitable for oil field exploitation

A composite flooding and composite flooding technology, which is applied in drilling compositions, chemical instruments and methods, etc., can solve the problem of increasing the difficulty of injection technology and treatment of produced fluid, and cannot reduce oil-water interfacial tension and reduce polymer viscoelasticity, etc. problem, to achieve the effect of flexible injection mode, good oil displacement effect and ultra-low interfacial tension

Active Publication Date: 2012-08-01
PETROCHINA CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, these methods still have shortcomings. Polymer flooding cannot reduce the interfacial tension of oil and water, so it is weak in improving oil displacement efficiency; both ASP flooding and foam composite flooding contain alkali, and a series of Negative effects, such as reducing the viscoelasticity of polymers, increasing the difficulty of injection process and production fluid treatment, increasing costs, etc.

Method used

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  • Composite foam flooding method suitable for oil field exploitation
  • Composite foam flooding method suitable for oil field exploitation
  • Composite foam flooding method suitable for oil field exploitation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] In this embodiment, the foamability and foam stability of the foaming agent are tested by using a foam scanner. The test method is as follows: at 45° C., inject carbon dioxide into the foam scanner at a flow rate of 30 mL / min for 5 minutes.

[0049] The volume of the foam produced at the end of the gas injection was used as the foamability evaluation index, that is, the foam volume (V). The time when the foam decays by half is used as the foam stability evaluation index, that is, the foam half-life (t). Foam Composite Index (FCI) can consider both foam volume and foam half-life, FCI=3Vt / 4. A TX500C spinning drop interfacial tensiometer was used at 45°C and 5000 rpm. Measure the interfacial tension of oil and water for 2 hours under the rotating speed of 3 , the freezing point is 31°C, the acid value is 0.09mgKOH / g, the wax content is 27.85%, and the sulfur content is 0.13%). The foam comprehensive index and interfacial tension of different foaming agents are shown in...

Embodiment 2

[0055] This example provides a foam composite flooding method. The man-made three-layer heterogeneous positive rhythm core (size 4.5cm×4.5cm×30cm) is selected to simulate the formation, and the coefficient of variation of the permeability is 0.72. Firstly, the core was evacuated to -1MPa at 45°C for two hours, saturated with simulated brine, and the measured pore volume was 157mL.

[0056] For the simulated oil (viscosity of 9.5cp) saturated with water in the core saturated Daqing Oilfield, the oil saturation is determined to be 73.2%, aged for more than 12 hours.

[0057] Carry out water flooding on the core saturated with simulated oil until the water content of the produced fluid is 98%, and after calculating the water flooding recovery, follow the following four steps to carry out foam composite oil flooding: pre-polymer slug, pre-adsorption auxiliary slug 1. Foam flooding main slug and polymer protection slug, after completing four steps, follow-up water flooding until th...

Embodiment 3

[0068] This embodiment provides a foam composite flooding method, wherein the specific operations and parameters of the four steps of foam composite flooding are as follows:

[0069] (1) Inject the pretreatment pre-polymer slug: the polymer is partially hydrolyzed polyacrylamide, its molecular weight is 25 million, the degree of hydrolysis is 23%, and the concentration is 0.15wt%; the inorganic salt is sodium chloride, and the concentration is 0.24 wt%; the viscosity of the pretreatment polymer slug is 74mPa·s, and the injection volume is 10% of the core pore volume.

[0070](2) Inject the auxiliary slug of foam composite flooding as a pre-adsorption slug: the surfactant is dialkyl alcohol amide polyoxyethylene ether (containing 4-6 polyoxyethylene groups, 16-18 alkyl carbons), the concentration is 0.3wt%; the foam stabilizer is partially hydrolyzed polyacrylamide, its molecular weight is 12 million, the degree of hydrolysis is 23%, and the concentration is 0.1wt%; the inorgan...

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Abstract

The invention relates to a composite foam flooding method suitable for oil field exploitation, comprising the following steps that: pretreated prepositive polymer plug is injected into the formation, and the injection volume of the polymer plug is 8-15% of the total pore volume of the formation; composite foam flooding auxiliary plug is injected into the formation, and the injection volume of the composite foam flooding auxiliary plug is 5-10% of the total pore volume of the formation; composite foam flooding main plug is injected into the formation, and the injection volume of the composite foam flooding main plug is 30-60% of the total pore volume of the formation; and follow-up protective polymer plug is injected into the formation, and the injection volume of the follow-up protective polymer plug is 10-20% of the total pore volume of the formation. With the adoption of the composite foam flooding method suitable for oil field exploitation, a good flooding effect can be obtained.

Description

technical field [0001] The invention relates to a foam composite oil flooding method suitable for oilfield development, which is a foam composite oil flooding method for improving crude oil recovery in tertiary oil recovery, and belongs to the technical field of oilfield development. Background technique [0002] At present, many oil fields at home and abroad have entered the stage of tertiary oil recovery, mainly using tertiary oil recovery methods such as thermal recovery, carbon dioxide flooding, and chemical flooding. Due to the heterogeneity of the underground reservoir and the relatively small remaining oil content, the tertiary oil recovery method that can expand the swept volume and improve the oil displacement efficiency is a hot spot that people pay attention to. [0003] Chemical flooding is one of the methods with the most potential for development. In chemical flooding, polymer flooding, ASP flooding and foam composite flooding are widely used tertiary oil recov...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/584C09K8/588C09K8/594
Inventor 刘宏生韩培慧孙刚高淑玲许关利武力军吕昌森曹瑞波
Owner PETROCHINA CO LTD
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