Method of restriction of bottom water and annulus overflows in production wells

FIELD: oil and gas industry.

SUBSTANCE: invention refers to methods of restriction of bottom water and annulus overflows in production wells. The method consists in pumping water and solution of sodium naphthenate into a well; then the procedure is repeated not less, than 3 times; also cement solution is pumped with addition of sodium naphthenate; while initially solution of sodium naphthenate and water is pumped and then additionally alumo-chloride is pumped. Volume ratio of sodium naphthenate and alumo-chloride can be 4:1.

EFFECT: upgraded efficiency of method due to effect of hydrophobisation of porous space, increased amount of forming cementing material, thermo-stabilisation of this material under conditions of high temperatures of bed (above 80°C) and creating more reliable isolation screen.

2 cl, 2 tbl, 3 dwg

 

The invention relates to the oil and gas industry, in particular to methods of restriction and exclusion zones water production in oil and gas-condensate wells, by alternating pump downhole components of the gel-forming substances.

There is a method of limiting the inflow of formation water into the well, comprising the sequential injection in water-in-reservoir portions diesel oil or alkaline wastes and aqueous solution of calcium chloride [see SU 1328488 A1, EV 43/32, 1987]. In the basis of the method lies physico-chemical transformation of waste alkaline diesel or oil into a solid mass upon contact with formation water, activated calcium chloride.

The disadvantages of this method include low structural-mechanical and adhesive properties of the resulting plugging material.

These disadvantages are eliminated in the method of restricting plantar water and cross-flows in wells, chosen as a prototype [see EN No. 2172825 C1, EV 43/32, 2000] and including leaching wells and portions of the injection water, cement and calcium chloride, providing that the hole through the exposed filter pump salt solution of polyvalent metal (calcium chloride), then water, then naphthenate solution of sodium or potassium or a mixture, this procedureafter at least 3 times, then pump cement mortar shut on the water, water / cement ratio which varies between 0.2-0.6, 0.5-2 m31 m thick layer with the addition in the amount of 0.5-10% by volume of cement additional naphthenate solution of sodium or potassium or mixtures thereof with the ratio of the naphthenate : water 1:2, followed by bursting into the well of the total weight of the reservoir water at the rate of 1-2 m31 m thick layer, and then a rinsing wells, sealing the mouth and endurance under pressure 24 hours

The disadvantages of the prototype can be attributed to the fact that the resulting chemical reaction between solutions of sodium naphthenate and calcium chloride plugging material is not sufficiently resistant to high temperature reservoir (80°). The products of the interaction of the reagents are characterized by a small number of sediment yield (capsules (material), and therefore do not have sufficient structural-mechanical properties and water-holding capacity, over time, are subject to erosion formation water, which in turn reduces the life of the formed insulating screen.

The technical result of the proposed method limits plantar water and cross-flows in wells - increase the efficiency of the method due to the effect of waterproofing porous what about the space, increasing the number of generated plugging material, its thermal stabilization under conditions of high reservoir temperatures (above 80°and creating a more reliable waterproofing of the screen.

This result is achieved by a method of restricting plantar water and behind-the-casing flows into the borehole involves the same process operations as the prototype, is distinguished by the sequence of injection of the reagents for the formation of the waterproof area and applying a solution of a salt of polyvalent metal is aluminum chloride. Thus, the method involves the sequential injection into the well at the beginning of a solution of sodium naphthenate, then as a buffer - water, then the solution of salt of polyvalent metal is aluminum chloride, with a volumetric ratio of naphthenate to the aluminum chloride is 4:1, this procedure is repeated at least 3 times, and then pumped cement mortar shut on the water, water / cement ratio which varies between 0.2-0.6, 0.5-2 m31 m thick layer with the addition in the amount of 0.5-10% by volume of cement additional naphthenate solution of sodium or potassium or mixtures thereof with the ratio of the naphthenate : water 1:2, followed by bursting into the well of the total weight of the reservoir water at the rate of 1-2 m31 m thick layer, and then a rinsing wells the ins, sealing the mouth and endurance under pressure 24 hours

Comparative analysis with the prototype shows that the distinctive features of the new method of restricting plantar water and behind-the-casing flows into the well is a necessary and sufficient condition characterizing the novelty of the subject matter of the invention, namely the sequence of injection of the reagents for the formation of the waterproof area and used as a solution of salt of polyvalent metal solution of aluminum chloride.

The proposed sequence of injection of the reagents in the first place, of a solution of sodium naphthenate, contributes to the synergistic effect of the processing layer, namely the presence of hydrocarbons in the composition of the sodium naphthenate allows gidrofobizirovan the pore space of the reservoir, reducing permeability for water, which, along with subsequent formation as a result of interaction with a solution of aluminum chloride plugging material reduces the likelihood of a breakthrough of water.

The task of the invention is to improve the insulation quality of the water in the well by hydrophobization of the pore space, increasing the number of cementing substance and its strength under high reservoir temperatures.

A solution of sodium naphthenate is an aqueous solution of sodium salts of naphthenic acids in the mixture of the mineral oil. The technical product is mylonaft high-viscosity oils acidol. Mylonaft has a buttery consistency, easily soluble in water, its color varies from light brown to dark brown. Get milonoff of petroleum products by alkaline treatment of the distillate treated with sulfuric acid, or by treatment of the corresponding distillate oil (kerosene, diesel) sodium hydroxide solution. Aqueous solutions of malonate possess surface-active properties, detergent action, good emulsifying ability. Sodium salts of naphthenic acids in the reactions with the electrolytes dissolved in the formation water, form a voluminous precipitate, creating an impenetrable screen of water.

Alumoxane is the tonnage of waste production, a byproduct of the processes of petrochemical synthesis according to THE 38.302163-89. Alumoxane is a transparent liquid containing 20-25% of the mass. the basic substance or the powder of light yellow or greenish color with a faint odor of hydrochloric acid. Alumoxane refers to hazardous compounds (IV hazard class according to GOST 12.1.007-76), miliaresion, does not freeze at low temperatures.

To calculate the stoichiometric amount of sediment in the interaction of naphthenate with solutions of salts does not appear who is one. To determine the optimum ratio of reactants, which is the formation of a maximum quantity of sludge produced by the interaction of aqueous solutions of salts of polyvalent metals (prototype - chloride and calcium - aluminium chloride) and a solution of sodium naphthenate were conducted the following laboratory tests. In a test tube was poured aqueous solutions of salts 10 cm3then added an aqueous solution of sodium naphthenate according to the scheme given in table 1. After the reaction has determined the amount of loose sediment, neasdon fluid and pH. The studies determined the volumetric ratio of sodium naphthenate solution of aluminum chloride 4:1 for maximum mass and volume of the sediment yield. When the interaction of these reagents under other equal conditions and equal volume ratios (4:1) increase the yield of the precipitate volume is 30%, by weight of 25% compared with the solution of calcium chloride on the prototype. PH pH neasdon fluid through 24 hours is restored to 8. Further, we point at a temperature of 80°With a mixture of reagents in a volume ratio of 4:1 sodium naphthenate and calcium chloride (the prototype) and sodium naphthenate and aluminum chloride (proposed method). In the first case there is postinnovation sediment under the influence of temperature.

Increasing the yield of the precipitate (plugging material) compared to the prototype in the interaction of the reagents is due to the special chemical properties of aluminium chloride, the molecules of which have a dimeric structure with covalent number 4 (Al2Cl6). In solutions of aluminium salts hydrolyzed with the formation of the complex:

In the interaction of the hydrolyzed form of aluminum chloride with sodium salts of naphthenic acids forms a strong complex. The prototype calcium chloride, participating in the exchange reaction joins two molecules of sodium naphthenate, because the valence of calcium +2, whereas aluminium chloride attaches four molecules of sodium naphthenate.

At the same time in the flushed zone, the formation of a precipitate of aluminium hydroxide Al(OH)3that adhesive on the surface of the pore channels, in addition to creating a waterproof area.

For methods of limiting water inflow main parameters determining the amount of filtration of produced water into the well per unit of time, are the permeability of rocks in the bottom zone of the collector on the water after the event water shutoff and minimum pressure gradient filter.

The method was verified in the laboratory by installing three-phase filter, ru is ment to simulate temperature and pressure conditions of the reservoir. The proposed formulation was tested on samples of core, pre-saturated formation water at a temperature of 80°C. Initially measured the permeability of water-saturated models for gas, water, and then carried out the injection of reagents and after exposure to the reverse reaction measured permeability for water. The results of laboratory studies insulating effect on the proposed formulation of the invention is 65-94%, while the minimum gradient filtering water remained at the same level. The prototype insulating effect is 35%, with a minimum gradient of water filtration decreased 1.5 times (table 2). In figure 1, 2, 3 shows graphs of the coefficient of filtration of samples of cores in the modeling process water shut-off prototype and the proposed method of the invention.

As can be seen from the above data, the use of solutions of sodium naphthenate and aluminum chloride leads to better technical result increased insulating effect washed in high temperature zones of the reservoir rocks and, ultimately, increase the production parameters wells.

3
The results of determining the volumetric quantity of sludge produced by the interaction of aqueous solutions of salts is polivalente metals and a solution of sodium naphthenate
Table 1
no experienceThe name of the solution of the metal Vsolution= 10 cm3Volume of an aqueous solution of sodium naphthenate, cm3The volume of solution General, cm3The volume of filtrate, cm3The amount of sludge, cm3the pH of the filtrate, pHNote
1An aqueous solution of calcium chloride 20% (the prototype)101918,80,27,5Under other equal conditions and equal volume ratios (4:1) increase the output of sediment by volume 30%
2152422210
3202926,82,210
4303836,41,611
5404943,85,211
6An aqueous solution of aluminum chloride 20%102018,11,93
7152521,63,4
8203026,53,54
9304035,44,64
10405043,26,84

Table 2
The way to handlePermeability after treatment, μm2The minimum pressure gradient filter, MPa/m
Offer0,006-0,0027,13
The placeholder0,0133,6

1. A method of restricting plantar water and cross-flows in wells, including injection into the well water, a solution of sodium naphthenate, the same procedure is repeated at least 3 times, followed by the injection of cement mortar with addition of sodium naphthenate, wherein the first downhole pump solution of sodium naphthenate, water, then advanced alumoxane.

2. The method according to claim 1, characterized in that the volume ratio of sodium naphthenate and aluminum chloride is 4:1.



 

Same patents:

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2 ex

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3 cl, 1 ex, 3 dwg

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20 cl, 5 ex, 3 tbl

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2 dwg, 5 ex, 4 tbl

FIELD: oil and gas industry.

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2 cl, 2 ex

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1 ex

Polymer compound // 2333347

FIELD: petroleum industry.

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1 tbl, 6 ex

FIELD: oil and gas industry.

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1 tbl

FIELD: mining.

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EFFECT: improved reliability and efficiency of insulation method, including insulation in wells in high-intake producing formations.

3 dwg

FIELD: oil and gas industry.

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EFFECT: reliability increase of isolation at repairing works of holes from water inflow.

3 cl, 2 tbl

FIELD: mining engineering, oil industry.

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EFFECT: increase of inflow isolation efficiency.

1 ex

FIELD: oil and gas production.

SUBSTANCE: invention relates to grouting mortars used for cementing casing pipes of gas, gas-condensate, and oil wells complicated by presence of formations with low hydraulic rupture pressure as well as presence of permafrost rocks. Light-weight grouting mortar contains 47.0-60.0% special-type cement, 6.6-11.8% clinoptilite as light-weight additive, and water. As a result, casing-pipe annulus incidents during boring and running wells are avoided owing to improved parameters of grouting cement, in particular increased sedimentation stability of mortar, dimensional stability and needed strength of cement stone at low positive and negative temperature in early hardening stages are achieved at simultaneous lowering of grouting mortar density.

EFFECT: improved performance characteristics of grouting mortar.

1 tbl

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