# US 2009/0260818 A1 · Microwave-Based Downhole Activation Method For Wellbore Consolidation Applications

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- Number: US 2009/0260818 A1
- Document ID: US20090260818A1
- Status: Published application
- Kind: A1
- Application number: 12/420,096
- Filed: 2009-04-08
- Published: 2009-10-22
- Earliest claimed: 2008-04-16
- Assignees: Schlumberger Technology Corporation
- Inventors: Sylvie Daniel; Mickael Allouche
- Web page: https://patentgrep.com/patent/US20090260818A1

## CPC

- E21B 21/003: {Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138)}
- E21B 33/138: Plastering the borehole wall; Injecting into the formation
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

Disclosed is a method and a tool for wellbore strengthening during drilling. Selected chemicals are mixed with the drilling fluid but do not react with it. The chemicals concentrate in the filtercake. A tool, which comprises a microwave source, is used to trigger polymerisation or crosslinking reactions within the filtercake downhole. The polymerisation or crosslinking reactions results in a film or a gel that strengthens the wellbore.

## Claims

### Claim 1

A method of constructing a borehole, the method comprising:
drilling the borehole using a drilling fluid comprising a chemical system capable of being polymerised;
allowing the drilling fluid to form a filter cake on at least part of the borehole wall in which the chemical system accumulates; and,
irradiating at least part of the filter cake with microwave radiation so as to cause the chemical system to polymerise or cross-link and so strengthen the filter cake.

### Claim 2 (depends on 1)

A method as claimed in claim 1, wherein the chemical system comprises methacrylate based systems, dimethyldiallylammonium chloride monomer, methylenebisacrylamide, polyethylene glycol and/or polydimethylallylammonium chloride.

### Claim 3 (depends on 1)

A method as claimed in claim 1, wherein a tool comprising a microwave radiation source is provided in the borehole for irradiation of the filter cake, the method comprising positioning the tool near to the part of the filter cake to be irradiated, and operating the microwave source to irradiate the filter cake.

### Claim 4 (depends on 3)

A method as claimed in claim 3, wherein the tool comprises at least one microwave antenna, the method comprising positioning the antenna near to the filter cake and using the antenna to irradiate the filter cake.

### Claim 5 (depends on 3)

A method as claimed in claim 3, comprising operating the microwave source to vary the level of microwave radiation used to irradiate the filter cake.

### Claim 6 (depends on 1)

A method as claimed in claim 1, comprising adjusting the level of the chemical system in the drilling fluid so as to obtain a concentration in the filter cake that can be cross-linked or polymerised by microwave radiation.

### Claim 7

Apparatus for use in construction of a borehole, comprising:
a tool body;
a source of microwave radiation located in the tool body; and
means for irradiating the borehole wall with microwave radiation from the source;
wherein the means for irradiating the borehole wall comprises an antenna that can be positioned near to the borehole wall, and the source is operable to initiate polymerisation or cross-linking in a chemical system in a filter cake on the borehole wall.

### Claim 8 (depends on 7)

A tool as claimed in claim 7, further comprising at least one arm mounted on the tool body, the microwave antenna being mounted at the end of the arm.

### Claim 9 (depends on 8)

A tool as claimed in claim 8, wherein the arm is extendible.

### Claim 10 (depends on 8)

A tool as claimed in claim 8, comprising multiple arms spaced axially and or azimuthally on the tool body.

### Claim 11 (depends on 10)

A tool as claimed in claim 10, wherein each arm carries an antenna that is connected to the microwave source.