Liquid for hydraulic seam rupture

FIELD: oil and gas production.

SUBSTANCE: invention relates to technological compositions used for increasing permeability of productive seams by carrying out hydrorupture of seam and can be used in extraction of gas and oil. Proposed liquid for hydraulic rupture of seam comprises the following components, wt.-%: potassium chloride, 6.00-7.00; sulfacell of sort 800, 1.30-2.00; aluminum sulfate, 0.15-0.80; disolvan, 0.03-0.05, and water, 90.15-92.52. Invention provides deceasing filtration, enhancing sand-retaining capacity, retention of filtration indices of critical zone of seam, availability of chemical reagents.

EFFECT: improved and valuable technical properties of liquid.

2 tbl

 

The invention relates to the field of oil and gas production, in particular to technological compositions used to increase the permeability of the productive formations through hydraulic fracturing (fracking), and can be used at oil and gas enterprises.

Known fluid for hydraulic fracturing (fracking)containing components, wt.%: the sulfite-alcohol yeast bard 31,72-39,76; potassium chloride 3,37-6,92; polyacrylamide 0,05-0,12; surfactant brand ML of 0.3-0.15 and produced water the rest (RF patent No. 1710710).

The disadvantage of this composition is low pescaderia ability. At high rheological properties of the fluid holds 10% sand. This fluid does not have destructible ability and not completely removed from the reservoir, which reduces the permeability of the productive formation after fracturing.

Closest to the claimed composition of the liquid is the fluid (RF patent No. 2138633). The liquid consists of a lignosulfonate modified by technical hexamethylenetetramine and urea, potassium chloride, as an additive contains a salt of trivalent metal is aluminum sulfate and produced water.

However, this fluid has the following disadvantages: liquid reduces the permeability of the bottom-hole formation zone is donkey fracturing, as lignosulfonates penetrate into the pore space of reservoir rocks, and the restitution coefficient of permeability reaches of 37.5%, pescaderia ability was not determined, although the data of measurements of static shear stress (SNA) indicate low pescaderia abilities. In addition, the complexity of this fluid makes its preparation and restricts its use in frac.

The task consisting in the claimed invention, to increase the productivity of wells after hydraulic fracturing.

The technical result achieved by the present invention, the solution to water-based hydraulic fracturing with low filter and high pescaderia ability, preserving the filtration characteristics of the bottom-hole formation zone, malotonnazhnogo available chemicals.

The task and the technical result is achieved by the fact that the fluid for hydraulic fracturing, including potassium chloride, aluminum sulfate and water, unlike the prototype further comprises alfacell (mark 800), surfactant - disolve, in the following ratio, wt.%:

alfacell (mark 800)
potassium chloride6,00-7,00
1,30-2,00
aluminum sulfate0,15-0,80
disolve0,03-0,05
water92,52-90,15

The inventive fluid for hydraulic fracturing differs from the prototype in that it contains alfacell, which performs the function of the gel-forming base, and a surfactant - disolve role of water-repellent and prevents the penetration of the aqueous phase liquids for hydraulic fracturing in the reservoir rocks. A crosslinking agent is aluminum sulfate. When dissolved in water with aluminum sulfate it breaks up into ions and produce none alfacell. The result is the formation of a strong gel.

For preparation of the inventive fluid for hydraulic fracturing used the following components.

Potassium chloride (KCl) HC according to GOST 4239-77, crystalline white powder (you can use technical potassium chloride - waste production of potash fertilizers).

Alfacell on THE 2231-013-32957-01, the white powder is used to stabilize and reduce the rate of filtration and as a gelling. Produced by ZAO polycell" Vladimir.

Aluminum sulfate according to GOST 12966-86, white powder, soluble in water. Manufacturer JSC And umini of Kazakhstan" Kazakhstan.

Disolve 4490 - surfactant. Is a light liquid density of from 950 to 970 kg/m3. Manufacturer - the company "Corgan Germany.

Technology of preparation of fluids for hydraulic fracturing in the laboratory is as follows: water is injected estimated number of potassium chloride, stirred until complete dissolution and then introduced alfacell, the estimated quantity of aluminum sulfate, disolve. Next, the liquid is mixed in the mixer for 30 minutes with a speed of 500-1000 rpm and left to rest for 2-3 hours to form a gel.

The parameters of the gel was determined on standard devices, the static shear stress is a unit of SNC-2, plastic viscosity and dynamic shear - rotational viscometer FANN-35A.

Pescaderia ability was defined when introduced into 100 ml liquid 100 g of proppant. When mixing the proppant is evenly distributed in the liquid, and sedimentation stability was determined in a measuring cylinder (table 1). High pescaderia the ability of the liquid ensures the success of hydraulic fracturing, because no prezhdevremennogo loss of proppant to the process of hydraulic fracturing. The recovery coefficient of permeability after penetration of the liquid fracturing in the rock sample with a permeability of 3.8· 10-3was 73.1% (table 2).

Due to improvement of technological parameters increases the effectiveness of the proposed liquid when conducting hydraulic fracturing and maintenance of the filtration characteristics of bottom-hole formation zone, which ensures an increase in the current production wells.

Table 1
The composition and properties of fluids for hydraulic fracturing
Indicators gel
Composition, wt.%Plastic viscosity, μMPa·Static shear stress Θ, 1/10, DPAFiltering, cm3/30 minPescaderia ability, hViscosity,
Fluid hydraulic fracturing declare34,077,0/86,04,0to 12.025,0
Potassium chloride6,00-7,00
Alfacell (mark 800)1,30-2,00
Aluminum sulfate0,15-0,80
Disolve0,03-0,05
Water92,52-90,15
Fluid hydraulic fracturing (prototype)
Technical lignosulfonates modified hexamethylenetetramine and
urea40,98-43,31-5,1/5,70,5-21,0
Potassium chloride3,70-4,32
Aluminum sulfate0,52-1,03
Produced water54,80-48,66

Table 2
Evaluation of the effect of the penetration of liquids for hydraulic fracturing on the filtration characteristics of the rocks
Mine, wellFluidThe permeability, K, 1·10-3μm2Porosity, %Residual water saturation, % Permeability to kerosene,

K, 1 · 10-3μm2
The recovery coefficient of permeability, %
to experienceafter the experience
Yamburg, SLE. 413declare73,119,133,5of 31.823,273,1
Yamburg, SLE. 413the placeholder28,214.4V35,418,94,637,5

Fluid for hydraulic fracturing, including potassium chloride, aluminum sulfate and water, wherein the liquid further comprises alfacell mark 800, surfactant - disolve in the following ratio, wt.%:

potassium chloride6,00-7,00
alfacell mark 8001,30-2,00
aluminum sulfate0,15-0,80
disolve0,03-0,05
water92,52-90,15



 

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