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Cleaning method of well wall with synthetic drilling fluid before cementing and used cementing prepad fluid

A drilling fluid and wellbore technology, which is applied in wellbore/well components, chemical instruments and methods, earth-moving drilling, etc. quality and other problems, to achieve the ideal cleaning effect, enhance the effect of wetting reversal, and improve the quality of cementing and cementation.

Inactive Publication Date: 2018-08-24
YANGTZE UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The difficulty of cleaning the borehole wall is especially that of oil-based drilling fluid and synthetic-based drilling fluid. This is because oil-based drilling fluid and synthetic-based drilling fluid will form an "oil film" on the borehole wall, and due to the effect of pressure difference, the There is a strong bonding effect between the well walls, if it cannot be cleaned effectively, it will inevitably affect the quality of cementing, thereby affecting oil and gas production
[0003] At home and abroad, a lot of research work has been done on the cleaning of oil-based drilling fluid or synthetic-based drilling fluid mud cake. For example, Chinese patent CN201310545773.3 discloses an oil-based drilling fluid mud cake cleaning fluid for shale gas development; Chinese patent CN201610438760.X discloses a microemulsion flushing fluid system suitable for oil-based drilling fluid; Chinese patent 201510990331.9 discloses a cementing flushing fluid system suitable for oil-based drilling fluid, which mainly solves the Cake cleaning is difficult, but the above-mentioned cementing flushing fluid system is not ideal for mud cake flushing of synthetic-based drilling fluid, which affects the cementation of the subsequent cementing hydrogel and the well wall

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] Unless otherwise specified, the amounts of the components described below refer to parts by mass.

[0063] Drilling fluid base fluid is the synthetic base fluid used in synthetic base drilling fluid;

[0064] The organic solvent is perfluoro-n-octane;

[0065] The flushing solution is 100 parts of water and 20 parts of flushing agent; the flushing agent is perfluorooctyl ammonium chloride iodide, isomeric tridecyl alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, fatty acid polyoxyethylene ester and propylene glycol Propyl ether is compounded according to the mass ratio of 5:5:25:25:40;

[0066] The isolation fluid is 100 parts of water, 2 parts of isolation agent and 10 parts of isolation flushing agent;

[0067] The release agent is compounded with a thickener, a cross-linking agent, a fluid loss control agent and a pH value alkaline regulator according to a mass ratio of 25:5:60:10; the thickening agent is xanthan gum, and the cross-linking agent ...

Embodiment 2

[0077] Cleaning reagent composition and consumption are with embodiment 1, and difference is:

[0078] The organic solvent is cyclohexane;

[0079] The flushing solution is 100 parts water, 100 parts flushing agent and 100 parts flushing weighting agent;

[0080] The washing weighting agent is barite;

[0081] The isolating fluid is 100 parts of water, 5 parts of isolating agent, 50 parts of isolating flushing agent and 100 parts of isolating weighting agent;

[0082] Wherein the viscosifier is coumarin, and the fluid loss reducer is hydroxypropyl starch;

[0083] The isolation weighting agent is barite.

[0084] Carry out cleaning according to the cleaning method of embodiment 1, difference is:

[0085] The contact time between the synthetic base fluid and the well wall is 3 minutes;

[0086] The contact time between the organic solvent and the well wall is 5 minutes;

[0087] The contact time between the flushing fluid and the well wall is 5 minutes;

[0088]The conta...

Embodiment 3

[0091] Cleaning reagent is with embodiment 1, and difference is:

[0092] The flushing solution is 100 parts water, 60 parts flushing agent and 50 parts flushing weight;

[0093] The flushing weighting agent is iron ore powder.

[0094] The isolation fluid is 100 parts of water, 3 parts of isolation agent, 30 parts of isolation flushing agent and 50 parts of isolation weighting agent;

[0095] The viscosifier is guar gum, the fluid loss reducer is carboxymethyl starch, and the isolation weighting agent is iron ore powder.

[0096] Cleaning method is with embodiment 1, and difference is:

[0097] The contact time between the synthetic base fluid and the well wall is 4 minutes;

[0098] The contact time between the organic solvent and the well wall is 6 minutes;

[0099] The contact time between the flushing fluid and the well wall is 8 minutes;

[0100] The contact time between spacer fluid and well wall is 4min.

[0101] By treating the mud cake of the synthetic base dri...

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PUM

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Abstract

The invention belongs to the technical field of oilfield cementing and particularly relates to a cleaning method of a well wall with synthetic drilling fluid before cementing and used cementing prepadfluid. By adopting the cleaning method provided by the invention, drilling fluid base fluid, an organic solvent, flushing fluid and spacer fluid are sequentially contacted with the well wall respectively, various components have synergetic effect, and the flushing effect of the drilling fluid to the well wall is improved. A result of the embodiment shows that by adopting the cleaning method provided by the technical scheme, the cleaning efficiency of the well wall can reach 90 percent or above.

Description

technical field [0001] The invention belongs to the technical field of oilfield cementing, and in particular relates to a method for cleaning a well wall before cementing with a synthetic base drilling fluid and a pre-cementing fluid used. Background technique [0002] In the process of oil extraction, the compatibility between drilling fluid and cement slurry is poor, which requires the replacement of pre-fluid before cementing to isolate the drilling fluid and clean the well wall to improve cementing. quality. The difficulty of cleaning the borehole wall is especially that of oil-based drilling fluid and synthetic-based drilling fluid. This is because oil-based drilling fluid and synthetic-based drilling fluid will form an "oil film" on the borehole wall, and due to the effect of pressure difference, the There is a strong bonding effect between well walls. If they cannot be cleaned effectively, the quality of cementing will be affected, which will affect oil and gas produ...

Claims

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Application Information

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IPC IPC(8): C09K8/40C09K8/52C09K8/467E21B37/06
CPCC09K8/40C09K8/467C09K8/52E21B37/06
Inventor 许明标李中由福昌李炎军孟文波
Owner YANGTZE UNIVERSITY
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