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Cross-linked acid and sand-carrying acid-fracturing method for ground with argillaceous dolomites

A cross-linked acid and surface technology, which is applied in the direction of earthwork drilling, mining fluid, wellbore/well parts, etc., can solve the problems of affecting the construction effect, uneven preparation of cross-linked acid, unsuitable argillaceous dolomite, etc.

Active Publication Date: 2013-05-08
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the dolomite and argillaceous dolomite in the research reservoir of this document are obviously different, and the content disclosed in this document is not applicable to complex reservoirs such as argillaceous dolomite
The process in the literature is only a single combination of cross-linked acid fracturing + cross-linked acid sand-carrying acid fracturing + closed acidification, only cross-linked acid fracturing without sand addition is used, and no relevant supporting technology is used in the main sand adding stage in the literature; The preparation method of the cross-linking acid is relatively complicated, and it is easy to cause uneven preparation of the cross-linking acid and affect the construction effect
[0009] At present, there is a lack of experience in the stimulation of argillaceous dolomite reservoirs at home and abroad, and there is no effective stimulation method suitable for it

Method used

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  • Cross-linked acid and sand-carrying acid-fracturing method for ground with argillaceous dolomites
  • Cross-linked acid and sand-carrying acid-fracturing method for ground with argillaceous dolomites
  • Cross-linked acid and sand-carrying acid-fracturing method for ground with argillaceous dolomites

Examples

Experimental program
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Effect test

example 1

[0061] Example 1: Well A

[0062] The well is an evaluation well, the lithology of the reservoir is argillaceous dolomite, the shale content is 45%, the perforated section is 1765.5-1788.1m, 17.8m / 8n, and the permeability is 10.5×10 -3 um 2 , the porosity is 11.7%, the acoustic time difference is 211.1us / m, the oil saturation is 42.15%, and the well temperature is 70°C. It is a typical low-temperature, low-porosity, low-permeability complex lithology reservoir, and conventional oil testing has no productivity. In order to minimize damage to reservoirs and fractures, control fracture height and increase the degree of indentation, form a support fracture with deep penetration and longer-lasting conductivity, achieve deep acid fracturing and increase the effective period of measures, the design uses high concentration The method of cross-linked acid acid fracturing + cross-linked acid-carrying acid fracturing + closed acidification. The specific method is:

[0063] (1) Accordi...

example 2

[0075] Example 2: Well B

[0076] The well is a pre-exploration well, the lithology of the oil layer is dolomitic mudstone, the shale content is 52%, the perforated section is 2335.9-2339.3m, 3.4m / 2n, the porosity is 13.5%, the acoustic time difference is 296.9us / m, the oil saturation 32.5%, the well temperature is 72°C, the well has no productivity in conventional oil testing. In order to ensure production capacity and fluidity, the design adopts cross-linked acid acid fracturing + cross-linked acid-carrying sand acid fracturing + closed acidizing process. The specific method is:

[0077](1) Through the analysis of small-scale fracturing test results, the closure pressure gradient of the pay zone reached 0.0244-0.0249MPa / m, the net pressure in the fracture was about 7-8MPa, and the liquid efficiency was about 40%. There was no obvious sign of multiple fractures from the G function. In view of this, the formal acid fracturing construction should appropriately increase the di...

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Abstract

The invention discloses a cross-linked acid and sand-carrying acid-fracturing method for a ground with argillaceous dolomites. Cross-linked acid-fracturing for the ground is combined with cross-linked acid sand-carrying acid-fracturing for the ground in the method, and in other words, the cross-linked acid and sand-carrying acid-fracturing method includes performing the cross-linked acid-fracturing in a prepad fluid stage; and performing the cross-linked acid sand-carrying acid-fracturing for the ground in a main sand feeding stage. The cross-linked acid and sand-carrying acid-fracturing method has the advantages that the process is simple, operation is facilitated, and a construction effect is obvious; the method can be widely applied to transformation construction for complex lithologic oil and gas reservoirs with argillaceous dolomites and the like; a deep-penetration prop fracture with durable flow conductivity can be formed to the greatest extent under the combined effect of acid-fracturing and sand-feeding acid-fracturing technologies, acid etching and propping effects are played for the fracture, and the flow conductivity of the artificial fracture and the productivity of an oil well are greatly improved.

Description

technical field [0001] The invention relates to the technical field of reservoir reformation, and more particularly relates to a cross-linked acid-carrying sand acid fracturing method on argillaceous dolomite ground. Background technique [0002] The argillaceous dolomite reservoir is a kind of complex lithology reservoir. This type of oil and gas reservoir not only has low porosity and permeability, but also has high shale content, so it needs reservoir reconstruction to be economically exploited. [0003] Before the present invention, conventional hydraulic fracturing methods were commonly used for reservoir stimulation of complex lithology reservoirs such as argillaceous dolomite, that is, using ground high-pressure pump sets to inject high-viscosity liquid into the well with a displacement that greatly exceeds the absorption capacity of the formation , create fractures in the formation near the bottom of the well and add a certain amount of proppant to support the fract...

Claims

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Application Information

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IPC IPC(8): E21B43/27
Inventor 张波薛承瑾蒋廷学张旭东李洪春王宝峰赵晓姚奕明卫然周林波
Owner CHINA PETROLEUM & CHEM CORP
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