NL2004711C2

NL2004711C2 - Process for shutting a fluid flow in a conduit.

Info

Publication number: NL2004711C2
Application number: NL2004711A
Authority: NL
Inventors: Franciscus Marie Groot
Original assignee: B & P Bodeminjectie B V
Priority date: 2010-05-12
Filing date: 2010-05-12
Publication date: 2011-11-15

Description

P30324NL00/AZE

PROCESS FOR SHUTTING A FLUID FLOW IN A CONDUIT

The present invention relates to a process for shutting a fluid flow in a conduit. In particular, the present invention relates to such a process when the fluid in the conduit is oil and/or gas. In another situation the fluid may comprise chemical compounds, including toxic chemical compounds.

5 In the production of oil and gas it is common to drill a well into a reservoir and produce the desired oil and gas via a system of pipelines. In recent years the production of oil and gas has taken place at ever-increasing depths offshore, e.g., in the Gulf of Mexico. Although these pipelines have usually been provided with closing mechanisms in case of an emergency, it is still possible that despite these mechanisms emergency situations may still 10 lead to leakages from the pipelines.

Therefore, there is still a need for a process that is able to shut the flow of fluids when an undesired flow, such as in case of leakages, takes place.

From US patent No. 4,899,819 a process is known in which a solidifiable gel is placed via a wellbore into the productive interval of a reservoir and the wellbore itself. The 15 gel solidifies into the reservoir and forms a gel plug into the wellbore. Before the gel is injected a chemical blowing agent is being used to create space in the reservoir so that the gel can enter the reservoir. After placing the gel plug, a cement is placed over the gel plug to suspend the production of oil from the wellbore. The gel material that is preferred in this process is stated to be hydropropyl guar cross-linked with transitional metals and ions 20 thereof. It is evident that in case of an emergency it is unfeasible to first inject a blowing agent, then a gel and finally a cement. Therefore this process is unsuitable to shut a fluid flow in a conduit when there is an emergency.

It is an object of the present invention to provide a process that will enable the skilled person to shut the flow of a fluid in a conduit with a minimum of actions and compounds.

25 Accordingly, the present invention provides a process for shutting a fluid flow in a conduit comprising - inserting a acrylamide gel into the conduit; - inserting a polymerization catalyst into the conduit, separately from the acrylamide gel; and 30 - allowing the acrylamide gel to polymerise to form a plug in the conduit.

The use of polyacrylamides and related polymers in the production of oil and gas is known. However, as shown in e.g., US patent No. 3,727,689, such polyacrylamides have been used in the hydraulic fracturing of underground formations in the reservoir.

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In this invention by acrylamide gel is understood a gel that contains acrylamide and/or methacrylamide. The gel may further comprise acrylic acid and/or methacrylic acid or metal salts of these acids. The nitrogen group of the acrylamide or methacrylamide monomer may be substituted by one or two alkyl groups, suitably with one to four carbon 5 atoms. The acrylamide gel may further comprise other ethylenically unsaturated monomers including vinyl sulphonic acid, vinyl benzyl sulphonic acid, vinyl benzene sulphonic acid, acrylonitrile, methyl acrylonitrile, vinyl alkyl ether, suitably of an alkyl group with one to four carbon atoms, vinyl chloride and maleic anhydride. Also oligomers of any of these monomers may be used in the process of the present invention.

10 The acrylamide gel is suitably inserted in a pumpable state. Suitably the acrylamide gel is inserted into the conduit in the form of an aqueous dispersion. It is desirable that sufficient acrylamide or methacrylamide is present in the monomer mixture to impart sufficient solubility and a desirably low viscosity to the mixture so that the mixture can be pumped to the conduit with out incurring undue effort. The person skilled in the art can 15 easily determine the concentration of water and the nature of the acrylamide monomer mixture to arrive at a desired viscosity. Typically, the amount of acrylamide and/or methacrylamide in the acrylamide gel ranges from 90 to 99%wt, based on the total of ethylenically unsaturated monomers.

Since the acrylamide gel is to polymerise to form a plug it is advantageous that the 20 acrylamide gel further contains a cross-linking compound. Examples of cross-linking compounds include divinyl benzene, divinyl ether, glycol diacrylate, glycol dimethacrylate, and methylene bisacrylamide. Methylene bisacrylamide is especially preferred. The amount of cross-linking compound can be relatively low; suitable concentrations range from 0.1 to 10%wt based on the total of the mixture of ethylenically monomers. By varying the amount 25 of cross-linking compound the skilled person is capable of varying the flexibility or stiffness of the plug that is being created.

The polymerization catalyst that is to be inserted into the conduit an be any conventional polymerization catalyst that is known to initiate radical polymerization. Suitable catalysts include water-soluble oxygen-containing catalysts, such as potassium or sodium 30 thiosulphate or bisulphate. Hydrogenperoxide, organic hydroperoxide or diazo compounds may also be used. Advantageously, the polymerization catalyst comprises a persulphate. The persulphate is suitably selected from the group consisting of an alkali metal persulphate, ammonium persulphate and mixtures thereof. Since an amine has the property to accelerate the radical formation of persulphate, preferably, an amine is added to the 35 acrylamide gel and/or the persulphate. When the polymerization catalyst is mixed with the acrylamide gel, the amine promotes the formation of radicals and hence accelerates the polymerisation. It is preferred to add at least a portion of the total amount of amine to the -3- persulphate polymerisation catalyst and insert a mixture of persulphate and amine into the conduit. In this way the interaction between the persulphate catalyst and the amine accelerator is facilitated. The amine is suitably selected from the group consisting of N,N,N’,N’-tetramethylethylene diamine and triethanol amine.

5 The polymerisation catalyst is suitably inserted into the conduit in the form of an aqueous solution. Especially when the acrylamide gel is also inserted into the conduit as an aqueous dispersion or solution this method of introducing the reactants has the advantage that the gel and the polymerization catalyst can be easily mixed. This is of particular advantage when the plug has to be created in a conduit at a considerable depth under sea 10 level.

The method for creating the plug in the conduit may be carried out in various conventional ways as will be appreciated by the person skilled in the art. One convenient way resides in that the acrylamide gel and/or the polymerization catalyst is inserted via a hose into the conduit. When one component has been inserted the other may be introduced 15 in a similar manner. However, it is advantageous to insert the acrylamide gel and the polymerization catalyst at more or less the same time. Thereto, both the acrylamide gel and the polymerization catalyst may be introduced into the conduit via two separate hoses. When both hoses have been inserted into the conduit both the gel and the catalyst are substantially simultaneously released. Since the mixing is easy and the polymerization rate 20 is fast, the plug is quickly formed.

In another embodiment, the acrylamide gel and/or polymerization catalyst is inserted into the conduit by drilling one or more holes in the wall of the conduit and by injecting the acrylamide gel and/or polymerization catalyst into the conduit via the one or more holes. When more holes are drilled the acrylamide gel and the polymerisation catalyst may be 25 inserted via one or more of the holes. When the reactants are inserted via more than one hole their mixing is promoted.

As indicated above, the process according to the present invention is very suitably applied in the field of oil and gas production. However, also in other fields this process may be applied. A suitable other field is the chemical industry. When a conduit that is being used 30 for the transport of chemical compounds is ruptured and these chemical compounds are leaking, the process of the present invention may provide a suitable solution to the situation that thus occurred. Therefore, the fluid in the conduit of the present process is suitably oil or gas or chemical compounds, or mixtures thereof.

The process according to the invention is conveniently used to stop a conduit from 35 leaking.

4

Clauses 1. Process for shutting a fluid flow in a conduit comprising - inserting a acrylamide gel into the conduit; 5 - inserting a polymerization catalyst into the conduit, separately from the acrylamide gel; and - allowing the acrylamide gel to polymerise to form a plug in the conduit.

2. Process according to clause 1, wherein the acrylamide gel comprises a cross-linking 10 compound.

3. Process according to clause 2, wherein the cross-linking compound is methylene bisacrylamide.

15 4. Process according to one or more of clauses 1 to 3, wherein the polymerization catalyst comprises a persulphate.

5. Process according to clause 4, wherein the persulphate is selected from the group consisting of an alkali metal persulphate, ammonium persulphate and mixtures thereof.

20 6. Process according to clause 4 or 5, wherein an amine is added to the acrylamide gel and/or the persulphate.

7. Process according to clause 6, wherein the amine is selected from the group consisting of 25 N,N,N’,N’-tetramethylethylene diamine and triethanol amine and mixtures thereof.

8. Process according to one or more of clauses 1 to 7, wherein the acrylamide gel and/or the polymerization catalyst is inserted into the conduit via a hose.

30 9. Process according to one or more of clauses 1 to 8, wherein the acrylamide gel and/or polymerization catalyst is inserted into the conduit by drilling one or more holes in the wall of the conduit and injecting the acrylamide gel and/or polymerization catalyst into the conduit via the one or more holes.

35 10. Process according to 9, wherein the fluid in the conduit is oil or gas or chemical compounds or mixtures thereof.

5 11. Use of the process according to one or more of clauses 1 to 10 to stop a conduit from leaking

Claims

A method for shutting off a stream of a fluid in a tube, comprising: - introducing an acrylamide gel into the tube; - introducing a polymerization catalyst into the tube, separate from the acrylamide gel; and - allowing the acrylamide gel to polymerize to form a plug in the tube. 10

The method of claim 1, wherein the acrylamide gel contains a crosslinking compound.

The method of claim 2, wherein the crosslinking compound is methylene bisacrylamide.

The method of any one of claims 1 to 3, wherein the polymerization catalyst comprises a persulfate.

The method of claim 4, wherein the persulfate is selected from the group consisting of an alkali metal persulfate, ammonium persulfate, and mixtures thereof.

The method according to claim 4 or 5, wherein an amine is added to the acrylamide gel and / or the persulfate. 25

The method of claim 6, wherein the amine is selected from the group consisting of N, N, N ', N'-tetramethylethylenediamine and triethanolamine, and mixtures thereof.

The method of any one of claims 1 to 7, wherein the acrylamide gel and / or the polymerization catalyst is introduced into the tube via a hose.

9. Method according to one or more of claims 1 to 8, wherein the acrylamide gel and / or the polymerization catalyst is introduced into the tube by drilling one or more holes in the wall of the tube and the acrylamide gel and / or polymerization catalyst in inject the tube through the one or more holes.

The method of any one of claims 1 to 9, wherein the fluid in the tube is oil or gas or a chemical compound or a mixture thereof.

11. Use of the method according to one or more of claims 1 to 10 to put an end to the leakage of a tube.