Method for determining whether water injection well needs to on-line acidification or not and acidification degree

A discrimination method and technology of water injection wells, applied in special data processing applications, instruments, electrical digital data processing, etc., can solve the problems of difficulty in on-site acquisition and large amount of data, and achieve easy data acquisition, low safety risks, and low operating costs Effect

Active Publication Date: 2017-06-20
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The purpose of the present invention is to overcome the problems of the prior art that many materials are required and the difficulty of on-site acquisition is large, and to provide a method for judging whether the water injection well is on-line acidified and the degree of acidification. With the advantages of low risk and simple operation, it can scientifically guide the online acidization of water injection wells, improve the effect of water injection development, and increase oil recovery

Method used

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  • Method for determining whether water injection well needs to on-line acidification or not and acidification degree
  • Method for determining whether water injection well needs to on-line acidification or not and acidification degree
  • Method for determining whether water injection well needs to on-line acidification or not and acidification degree

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Embodiment 1

[0050] In order to solve the problem that the existing technology needs a lot of data and it is difficult to collect on-site, this embodiment provides a decision-making method for whether the water injection well needs to be acidified online, including the following steps:

[0051] (1) Use the wellhead automatic pressure recorder to test the wellhead pressure drop of a single water injection well, draw the corresponding wellhead pressure drop curve of the water injection well, and obtain the single well wellhead pressure index PI value according to the wellhead pressure drop curve:

[0052]

[0053] In the formula: P(t) is the function of wellhead pressure of water injection well changing with time, the unit is MPa;

[0054] t is the test time, the unit is min.

[0055]The wellhead automatic pressure recorder can be a wellhead automatic pressure recorder with a model number of FYLΦ19-4602. The outer diameter of the wellhead automatic pressure recorder is Φ19mm, the instrume...

Embodiment 2

[0090] Take the online acidizing of well J1 as an example to describe in detail.

[0091] The oil reservoir to which Well J1 belongs is a delta front microfacies, the main layer is mainly ferrocalcite cementation facies and feldspar dissolution facies, and the reservoir rock is mainly lithic sandstone, which is tight and has poor physical properties. The middle depth of the oil layer in Well J1 is 2870m, the porosity of the main layer is 8.23%, and the permeability is 0.43×10 -3 μm 2 . After testing, the average dimensionless pressure index of the block where the well is located is 29.9, while the PI value of the well is 16.17MPa, the net water column pressure is 24.40MPa, the initial wellhead pressure before shutting down the well is 18.4MPa, and the friction calculation result is 0.45MPa, the dimensionless pressure index A of the well 1 is 38.4, greater than 20% of the dimensionless pressure index of the block, indicating that the underinjection well needs online acidizin...

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Abstract

The invention relates to a method for determining whether a water injection well needs to on-line acidification or not and the acidification degree. The method includes the following steps that 1, according to a measured wellhead pressure drop curve, a single-well wellhead pressure index PI value is obtained; 2, the water injection well bottom flowing pressure Pwf(t) and the well bottom pressure Pws (delta t) after the well shut-in time (delta t) are calculated; 3, the water injection well non-dimensional well bottom pressure decrease value delta p'wf (delta t) is calculated out; 4, the water injection well non-dimensional well bottom pressure index A is calculated out; 5, the sectional average non-dimensional well bottom pressure decrease value and the sectional average non-dimensional pressure index are calculated; 6, the sectional average non-dimensional pressure index is compared with the single-well non-dimensional pressure index to judge whether the water injection well needs to on-line acidification or not; 7, According to the non-dimensional pressure indexes before and after under-injected well acidification, whether the on-line acidification is complete or not is judged. The method had the advantages of being low in operation cost, low in safety risk and simple in operation, can achieve the scientific instruction on the on-line acidification of the water injection well, the water injection development effect is improved, and the oil field recovery rate is improved.

Description

technical field [0001] The invention belongs to the field of acidizing and plugging removal of water injection wells, and in particular relates to a method for judging whether a water injection well is acidified online and the degree of acidification. Background technique [0002] Normal water injection of water injection wells is an important means to ensure oilfield development and production, and the success of well selection is one of the main reasons affecting the effect of water well measures. [0003] At present, well selection techniques for stimulation measures are mainly based on well test interpretation and dynamic analysis. This type of method requires a lot of data and is difficult to collect on site. In my country, wellhead pressure drop curves of water injection wells in mine fields are very easy to obtain data. The wellhead pressure drop curves of water injection wells have been used in profile control and water shutoff, but neglected to provide interpretatio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F19/00
CPCG16Z99/00
Inventor 邓志颖张随望陆小兵王勇宋昭杰隋蕾王尔珍
Owner PETROCHINA CO LTD
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