Yield increase method for low-permeability wax-bearing oil well

A low-permeability, oil-well technology, used in earth-moving drilling, wellbore/well components, and production fluids, etc., can solve the problems of low production degree, poor water injection development effect, and high risk, and improve porosity and efficiency. Penetration performance, conducive to on-site promotion and application, targeted and operability effects

Active Publication Date: 2016-07-13
西安长庆同欣石油科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, this type of reservoir is generally developed by water injection, but the injection of water is easy to cause cold damage to the oil layer. After the oil layer is waxed, the development effect of water injection will be deteriorated. Therefore, the recovery degree of low permeability waxy oil reservoirs is generally not high at present. , less than 30%, therefore, there is an urgent need for a method that can significantly increase the recovery of low-permeability waxy reservoirs
[0003] Through literature search, the patent number "ZL03156478.x", titled "The Method of Steam Injection Thermal Recovery for Waxy Low Permeability Reservoirs", introduced a method of producing waxy low permeability reservoirs by combining steam huff and puff and steam flooding. The disadvantages of this invention are: (1) the cost of steam injection thermal recovery is high and the risk is high; (2) the corrosion and maintenance costs of the pipe string are high; (3) due to the low permeability of low permeability reservoirs and the poor fluidity of crude oil, steam injection Thermal recovery has a low rate of enhanced recovery, and the effect is limited; (4) The selection conditions for oil reservoirs are relatively harsh, especially for the thickness and depth of oil reservoirs; (5) High waxy crude oil is lifted in the wellbore During the process, due to the drop in temperature, it is easy to precipitate wax, which will lead to the blockage of the wellbore of the oil well

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Well A in an oilfield, the temperature of the reservoir is 70°C, and the permeability is 18×10 -3 μm 2 , crude oil wax content 25.6%, oil layer thickness 3.4m, permeability coefficient of variation 0.9, oil well depth 2560m, this well daily oil production 3.2t before the test, water cut 96.8%, utilize the method of the present invention to carry out field test in oil well A, specifically The implementation steps are as follows:

[0028] (1) Screening of oil wells

[0029] The selection criteria for oil wells are: reservoir temperature less than 85°C, permeability less than 50×10 -3 μm 2 1. The wax content of crude oil is greater than 10%, the thickness of the oil layer is greater than 1m, the coefficient of variation of permeability is less than 1, and the depth of the oil well is less than 2500m; the oil layer temperature of oil well A is 70°C, and the permeability is 18×10 -3 μm 2 , crude oil wax content 25.6%, oil layer thickness 3.4m, permeability coefficient o...

Embodiment 2

[0038] Oil well B in an oil field, the reservoir temperature is 58°C, and the permeability is 23×10 -3 μm 2 , crude oil wax content 33.2%, oil layer thickness 2.7m, permeability coefficient of variation 0.6, the depth of oil well 1530m, this well daily oil production 1.3t before the test, water cut 97.8%, utilize the method of the present invention to carry out field test in oil well B, specifically The implementation steps are as follows:

[0039] (1) Screening of oil wells

[0040] The selection criteria for oil wells are: reservoir temperature less than 85°C, permeability less than 50×10 -3 μm 2 1. The wax content of crude oil is greater than 10%, the thickness of the oil layer is greater than 1m, the coefficient of variation of permeability is less than 1, and the depth of the oil well is less than 2500m; the oil layer temperature of oil well B is 58°C, and the permeability is 23×10 -3 μm 2 , crude oil wax content 33.2%, oil layer thickness 2.7m, permeability coeffici...

Embodiment 3

[0049] Well C in an oilfield, the temperature of the reservoir is 77°C, and the permeability is 9×10 -3 μm 2 , crude oil wax content 22.3%, oil layer thickness 4.8m, permeability coefficient of variation 0.7, oil well depth 1768m, this well daily oil production 1.3t before the test, water cut 98.2%, utilize the method of the present invention to carry out field test in oil well C, specifically The implementation steps are as follows:

[0050] (1) Screening of oil wells

[0051] The selection criteria for oil wells are: reservoir temperature less than 85°C, permeability less than 50×10 -3 μm 2 , The wax content of crude oil is greater than 10%, the thickness of the oil layer is greater than 1m, the coefficient of variation of permeability is less than 1, and the depth of the oil well is less than 2500m; the oil layer temperature of oil well H is 77°C, and the permeability is 9×10 -3 μm 2 , crude oil wax content 22.3%, oil layer thickness 4.8m, permeability coefficient of v...

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PUM

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Abstract

The invention belongs to the technical field of tertiary oil recovery, and particularly relates to a yield increase method for a low-permeability wax-bearing oil well.The method specifically includes the following steps of oil well screening, oil well fracturing, single-well huff and puff processing of the oil well, oil well shaft processing and the field test effect evaluation stage.The method has the advantages of being simple in process and high in operability and is beneficial to field application and popularization.The method is high in pertinence, serial process measures are selected in a targeted mode according to the characteristics of the low-permeability wax-bearing oil well, and therefore the yield and validity period of the oil well can be substantially increased, the single-well oil increment is larger than 500 t, the validity period is longer than 3 years, and the input-output ratio is larger than 1:5.Therefore, the method can be widely applied to field tests of yield increase of the low-permeability wax-bearing oil well.

Description

technical field [0001] The invention relates to oil extraction technology, in particular to a method for increasing production of low-permeability waxy oil wells. Background technique [0002] Low permeability waxy reservoir, the reservoir permeability is lower than 50×10 -3 μm 2 , the wax content of the crude oil in the oil layer is greater than 10%, and the wax precipitation point of the crude oil is higher, which is slightly lower than the temperature of the oil layer; as long as the formation is degassed, the viscosity of the crude oil rises rapidly, and the wax is easy to precipitate in the oil layer. At present, this type of reservoir is generally developed by water injection, but the injection of water is easy to cause cold damage to the oil layer. After the oil layer is waxed, the development effect of water injection will be deteriorated. Therefore, the recovery degree of low permeability waxy oil reservoirs is generally not high at present. , less than 30%, there...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B37/06
CPCE21B37/06E21B43/26
Inventor 刘琴
Owner 西安长庆同欣石油科技有限公司
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