RU2763553C2 - Enzymatic destructor for process liquids - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil and gas industry and can be used in technology of formation hydraulic fracturing, well killing, repair and insulation works in oil and gas wells, where the process liquids used are cross-linked and non-crosslinked polymer systems based on guar gums, derivatives of cellulose and starch derivatives. Enzymatic destructor for destruction - process liquids destruction in technologies of formation hydraulic fracturing, well killing and repair insulation works in oil and gas wells, where the process fluids used are cross-linked and non-crosslinked guar-based resin systems, non-crosslinked polymer systems based on cellulose derivatives or starch derivatives, containing an enzyme β-mannanase, additionally contains xylanase and amylase, and carrier or solvent, where the carrier used is a natural polymer - food starch; and as a solvent - mono- or two- or triatomic alcohol, or a mixture thereof and water, in form of drinking water, with the following ratio of components, wt. %: β-mannanase 0.0001–0.001, xylanase 0.0001–0.001, amylase 0.0001–0.001, natural polymer is the rest, or β-mannanase 0.0001–0.001, xylanase 0.0001–0.001, amylase 0.0001–0.001, single- or double- or triatomic alcohol or their mixture 40.0–60.0, water is the rest.

EFFECT: technical result is enabling accurate destructor dosing, which increases efficiency of its use, as well as use at temperature of 20-80°C and lower.

1 cl, 9 ex, 5 tbl

Description

The invention relates to the oil and gas industry and can be applied in technologies for hydraulic fracturing, well killing and repair and insulation works in oil and gas wells, where crosslinked and non-crosslinked polymer systems based on guar gums, cellulose derivatives and starch derivatives are used as process fluids.

Known composition for the destruction of a cross-linked gel based on guar gum comprising an organic peroxide and a peroxide activator - an ester of a carboxylic acid with a number of carbon atoms of 2-8 in the following ratio, wt %: organic peroxide 51-70; ester 30-49 and with a peroxide activator content of 2-14% by weight of guar gum (RU No. 2487157, 2013).

The disadvantages of this invention are:

Firstly, the complexity of calculating the exact dosage of the destructor, and if the destructor is not enough, then the gel is not completely destroyed. And if there is an excess amount of the destructor, then premature destruction of the gel will occur;

Secondly, this destructor is limited in applicability, it can only be used for the destruction of gels based on guar gum in hydraulic fracturing technologies;

Thirdly, this destructor is not applicable at low temperatures, for example, at temperatures below 20°C.

Closest to the invention is a method of hydraulic fracturing using the enzyme mannanohydrolase as a destructor, which includes introducing into the formation, under pressure sufficient to create or expand fractures in the formation, a hydraulic fracturing fluid having a pH of from 8.5 to 11.0 , comprising: a hydratable polymer selected from the group consisting of unmodified guars and modified guars; a crosslinking agent for crosslinking the hydrated polymer to form a polymer gel; and an enzyme destructor containing the enzyme mannanohydrolase, which has an amino acid sequence that is at least 90% homologous to the amino acid sequence of SEQ ID NO: 2 (RU No. 2014123560, 2015).

The disadvantages of this invention are:

Firstly, the complexity of the exact dosage of the destructor, since it is used in its pure form;

Secondly, the use of one enzyme in the destructor also limits its applicability, it can only be used for the destruction of gels based on guar gum in hydraulic fracturing technologies.

The technical task of the present invention is to provide:

Firstly, the possibility of accurate dosage of the destructor, which makes it possible to avoid incomplete or premature destruction;

Secondly, the possibility of using the destructor not only for process fluids based on guar resins in hydraulic fracturing technologies, but also on the basis of cellulose derivatives and starch derivatives in hydraulic fracturing, killing and repair and isolation works in gas and oil wells;

Thirdly, the possibility of using this destructor not only at temperatures from 20 to 80°C, but also at temperatures below 20°C.

This technical problem is solved by the fact that the enzyme-based destructor for process fluids containing β-mannanase additionally contains xylanase, amylase and a carrier, which is a powdered polymer of natural origin or a solvent, which is used as one, or two, or trihydric alcohol, or a mixture thereof and water, which are essential features of the invention.

The essence of the invention is as follows. An enzyme destructor is proposed for technologies of hydraulic fracturing, well killing and repair and isolation works in oil and gas wells, where crosslinked and non-crosslinked polymer systems based on guars, cellulose derivatives and starch derivatives are used as process fluids, containing the enzyme β-mannanase, which additionally contains xylanase and amylase and a carrier or solvent, where a polymer of natural origin - food starch is used as a carrier; and as a solvent, one-, or two-, or trihydric alcohol is used, or a mixture thereof and water, which is drinking water, in the following ratio of components, wt %:

- β-mannanase 0.001-0.0001, - xylanase 0.001-0.0001, - amylase 0.001-0.0001, - natural polymer rest,

or

- β-mannanase 0.001-0.0001, - xylanase 0.001-0.0001, - amylase 0.001-0.0001, one-, or two, or trihydric alcohol, or their mixture 40.0-60.0, - water rest.

For research were used:

β-mannanase produced by Tandem-Industry LLC;

Xylanase produced by Microbioprom Concern LLC;

Amylase produced by Microbioprom Concern LLC;

Potato starch according to GOST R 53876-2010.

Corn starch according to GOST 32159-2013.

Technical starch for drilling according to STO Gazprom RD 2.1-150-2005.

Ethanol according to GOST 5962-2013;

Ethylene glycol according to GOST 19710-83;

Glycerin according to GOST 6259-75;

Drinking water according to GOST R 51232-98.

To prepare a dry enzyme destructor, it is necessary to first prepare a mixture of β-mannanase, xylanase and amylase enzymes in a dry form, then apply the mixture to food starch by mixing until homogeneous.

To prepare a liquid enzyme destructor, it is necessary to first prepare a mixture of β-mannanase, xylanase and amylase enzymes in dry form, then add the dry mixture with stirring to a water-alcohol solution containing one-, or two-, or trihydric alcohol, or their mixture and water , and stir until smooth.

The lower and upper limits of the range of concentrations of the components of the enzyme destructor is determined by the need to obtain the required properties of the enzyme destructor.

Below are examples of obtaining the described enzyme destructor.

Example #1.

To prepare 1000.0 g of a dry enzyme destructor, it is necessary to take 0.1 g of β-mannanase, 0.5 g of xylanase, 1.0 g of amylase in dry form and mix with each other until homogeneous. Then take 998.4 g of potato starch and mix it with the enzyme mixture until smooth.

Example #2.

To prepare 1000.0 g of a dry enzyme destructor, it is necessary to take 1.0 g of β-mannanase, 0.1 g of xylanase, 0.5 g of amylase in dry form and mix until homogeneous. Then take 998.4 g of corn starch and mix it with the enzyme mixture until smooth.

Example #3.

To prepare 1000.0 g of a dry enzyme destructor, it is necessary to take 0.5 g of β-mannanase, 1.0 g of xylanase, 0.1 g of amylase in dry form and mix until homogeneous. Then take 998.4 g of technical drilling starch and mix it with the enzyme mixture until smooth.

Example number 4.

To prepare 1000.0 g of a liquid enzyme destructor according to the second recipe, it is necessary to take 0.1 g of β-mannanase, 0.5 g of xylanase, 1.0 g of amylase in dry form and mix until homogeneous. Then prepare a water-alcohol solution from 400.0 g of ethanol and 598.4 g of water. Then add the enzyme mixture to the water-alcohol solution and mix until smooth.

Example number 5.

To prepare 1000.0 g of a liquid enzyme destructor according to the second recipe, it is necessary to take 1.0 g of β-mannanase, 0.1 g of xylanase, 0.5 g of amylase in dry form and mix until homogeneous. Then prepare a water-alcohol solution from 500.0 g of glycerol and 498.4 g of water. Then add the enzyme mixture to the water-glycol solution and mix until smooth.

Example number 6.

To prepare 1000.0 g of a liquid enzyme destructor according to the second recipe, it is necessary to take 0.5 g of β-mannanase, 1.0 g of xylanase, 0.1 g of amylase in dry form and mix until homogeneous. Then prepare a water-alcohol solution from 600.0 g of ethylene glycol and 398.4 g of water. Then add the enzyme mixture to the water-glycol solution and mix until smooth.

Example number 7.

To prepare 1000.0 g of a liquid enzyme destructor according to the second recipe, it is necessary to take 0.1 g of β-mannanase, 0.5 g of xylanase, 1.0 g of amylase in dry form and mix until homogeneous. Then prepare a water-alcohol solution from 200.0 g of ethanol, 200 g of ethylene glycol and 598.4 g of water. Then add the enzyme mixture to the water-alcohol solution and mix until smooth.

Example number 8.

To prepare 1000.0 g of a liquid enzyme destructor according to the second recipe, it is necessary to take 1.0 g of β-mannanase, 0.1 g of xylanase, 0.5 g of amylase in dry form and mix until homogeneous. Then prepare a water-alcohol solution from 200.0 g of ethanol, 300.0 g of glycerol and 498.4 g of water. Then add the enzyme mixture to the water-glycol solution and mix until smooth.

Example #9.

To prepare 1000.0 g of a liquid enzyme destructor according to the second recipe, it is necessary to take 0.5 g of β-mannanase, 1.0 g of xylanase, 0.1 g of amylase in dry form and mix until homogeneous. Then prepare a water-alcohol solution from 100.0 g of ethylene glycol, 500.0 g of glycerol and 398.4 g of water. Then add the enzyme mixture to the water-glycol solution and mix until smooth.

Tables 2-5 show the results of the destruction of process fluids

As can be seen from tables No. 2-5, the enzyme destructor prepared according to examples No. 1-9 completely destroys crosslinked and non-crosslinked polymer systems based on guar gum, non-crosslinked polymer systems based on cellulose derivatives, non-crosslinked polymer systems based on starch derivatives for a certain period of time, both at a temperature of 20°C and at a lower temperature of 10°C.

Thus, the use of the proposed enzyme destructor makes it possible to solve the problems of complete destruction of the polymer gel in process fluids based on cross-linked and non-cross-linked polymer systems, where guar gums, cellulose derivatives and starch derivatives are used as a polymer in hydraulic fracturing, killing and repair and insulation works in gas and oil wells.

Claims (4)

Enzymatic destructor for destruction - destruction of process fluids in hydraulic fracturing technologies, well killing and repair and insulation works in oil and gas wells, where crosslinked and non-crosslinked polymer systems based on guar gum, non-crosslinked polymer systems based on cellulose derivatives are used as process fluids or starch derivatives containing the enzyme β-mannanase, characterized in that it additionally contains xylanase and amylase and a carrier or solvent, where a polymer of natural origin - food starch is used as a carrier; and as a solvent, one-, or two-, or trihydric alcohol is used, or a mixture thereof and water, which is drinking water, in the following ratio of components, wt %.: β-mannanase 0.0001-0.001 Xylanase 0.0001-0.001 Amylase 0.0001-0.001 natural polymer rest or β-mannanase 0.0001-0.001 Xylanase 0.0001-0.001 Amylase 0.0001-0.001 One, or two, or trihydric alcohol or their mixture 40.0-60.0 Water rest