Formation bottom area treatment composition

FIELD: oil and gas production.

SUBSTANCE: composition contains 0.05-2.5% of hydrophobic power, 0.05-10% of ethylene/vinyl acetate copolymer, and organic solvent. Composition intensifies oil production owing to increased effective radius of formation bottom area treatment, prevention of moistening inversion effect upon fall of hydrophobic agent concentration, and, consequently, decreased volume of simultaneously produced water.

EFFECT: increased oil production, prolonged overhaul period, improved environmental safety, and lowered production expenses.

2 tbl, 3 ex

 

The invention relates to the oil industry and is designed to increase oil production due to the impact of bottom-hole zone of the well.

Mining using artificial or natural active water regime at a later stage of development is accompanied by the production of a large volume of associated water reservoir, pumping, food preparation and disposal of this water requires significant material costs, and increases the environmental burden in the region of oil and gas production. One of the ways to solve this problem is the quality of the waterproofing works on wells.

Known use as a water-repellent water-repellent agent silicon dioxide in an organic solvent with a concentration of from 0.05 to 2 wt.% /patent RF №2105142, IPC 6 E 21 In 43/22, publ. 20.02.98/.

It helps to increase the flow rate of oil wells up to 2.5 times with a slight decrease in water content of produced fluids (5-10%).

Disadvantages of the use of this agent are relatively low efficiency to increase the output of the wells and a slight decrease in water content of produced fluids.

Known use as hydrophobic water-repellent powder for enhanced recovery of oil hydro is one of dispersed material based on silicon dioxide or a metal oxide, the surface which is activated carbonates of alkali metals, chemically modified Organoelement compound of General formula Cl4-nSiRnwhere n=1-3, R=H, methyl-, ethyl-, Cl -, methyl-, phenyl-, with the subsequent further processing of the compound selected from the group consisting of tetramethoxysilane, tetraethoxysilane, the oligomer polymethyl(ethyl)siloxane,

polymethylsilane in quantities of 0.5-1.0 wt.%./RF patent №2089499, IPC 6 01 33/18, 09 With 1/281, 3/12, publ. 10.09.97/.

For processing bottom-hole zones of oil wells apply the suspension of hydrophobic powder in an organic solvent per linear meter effective area of the power layer.

The most effective known hydrophobic powders for processing production wells in a hydrocarbon solvent with a concentration of not less than 0.5-2%, low concentrations may cause flooding of the bottom wells.

During long-term operation inevitably lower concentrations (0.5 to 2%) of hydrophobic powder on the surface of the collector due to its desorption and removal of the bottom-hole formation zone (PPP). This has a negative effect on the duration of action of hydrophobic agent, and, in addition, at lower concentrations there is an inversion of wetting, that is, the surface of separation of the phases becomes hydrophilic, and there is tons danger of breaking the produced water to the bottom oil wells, that will lead to adverse effects (increase of produced water). In addition, it shortens the turnaround activities for production wells.

The disadvantages of the known hydrophobic agents is that uploading them at the highest possible concentrations often leads to plugging of the pore space of the bottomhole zone of the formation due to the comparability of the pore size with a particle size of suspensions of hydrophobic powder, which limits their use in low-permeability reservoirs. Modified oxides are very expensive components, and use them in the processing of wells, at the late stage of development unprofitable.

The task of the invention is to provide a composition cheap hydrophobic reagents with high adhesive properties, which intensify the oil recovery by increasing the depth of penetration (effective radius processing PPP) water-repellent agent into the reservoir when using the true solution in the composition with suspensions of hydrophobic powders; prevent the inverse effect of wetting in the fall concentrations of hydrophobic agent and, consequently, reducing produced water, increasing the period of turnaround activities for production wells; the appreciation is the sustainability of the development of oil reservoirs; the reduction of oil production.

The problem is solved by the development and use of the composition for treatment of bottom-hole formation zone, including hydrophobic powder in an organic solvent. Moreover, the composition further comprises a copolymer of ethylene with vinyl acetate in the following ratio, wt.%: a copolymer of ethylene with vinyl acetate 0.05 to 10, 0mm; hydrophobic powder of 0.05-2.5; organic solvent else.

Offered as a hydrophobic agent is a copolymer of ethylene and vinyl acetate (CMEA) can be any brand. Use it for oil production is unknown. CMEA is a high-molecular compound related to the polyolefins. He has enhanced adhesion to various materials and is widely used in printing, furniture, footwear and other industries.

In table. 1 presents the evaluation of the water-repellent action of the compounds, depending on their concentration in the organic solvent in the table. 2 - change the relative permeability of water and oil in the processing of 0.1% claimed hydrophobic agent in an organic solvent.

The method of estimating water-repellent action of lifting the water in the capillary.

The solution is hydrophobic agent in a hydrocarbon solvent impregnated activated and reactivenav the hydrated silica sand with a diameter of 0.14 to 0.25 μm, activated sand - hydrophilic (Hcl treated) and inactivated sand (not processed Hcl, partially hydrophobic). Dried in a drying Cabinet for twenty-four hours or until dry. Sand, soaked and dried, fill through the funnel in the tube height 16 see Condense laboratory shaker 250 cycles per minute at an amplitude of 4 for 15-20 minutes. Filled tubing with active and neaktivirovannye sand treated with the investigated solutions, put in a conical flask with distilled water (always the same). Note the time. Stand for five hours, measuring the height of rise of water in capillary through every 10 minutes. The obtained results are processed and build graphs of wetting and diagrams of the effect.

Example 1.At the present methodology 1 gram of the prepared solution of CMEA 0,1% + hydrophobic powder ("Policy", produced by JSC "RITEK" RF patent No. 2089499) 0.1% in diesel fraction (diesel fuel DT) impregnated with quartz sand (activated and non-activated) with a diameter of 0.14 to 0.25 μm and a mass of 8 grams. Dried within twenty-four hours or in a drying Cabinet to dry. Sand, soaked and dried, rolled up in a tube height of 16 cm with a Shoe through the funnel. Condense laboratory shaker 250 cycles per minute at an amplitude of 4 for 15-20 min is so Filled tubing with active and neaktivirovannye sand, treated with a solution of CMEA (0,1%)+ hydrophobic powder (0.1%) DT, put in a conical flask with distilled water (always the same). Note the time. Stand for five hours, measuring the results of every 10 minutes. The obtained results are processed and build graphs of wetting and diagrams of the effect.

Example 2.Analogously to example 1, but as the hydrophobic powder is used “Quartz” production of LLC “Quartz” (on THE 245810-001-50618596-2000) with a concentration of 0.1 wt.%.

Similarly were conducted other experiments, the results of which are given in table. 1.

However, when the transition to industrial testing is necessary to take into account the complex geological and physical conditions: the heterogeneity of sites with different degree of saturation and the water content, the degree of desorption of water-repellent with the breed, taking into account the fact reduce the concentration of hydrophobic powder and a possible hydrophilizing his behavior, which can lead to negative results. It was therefore conducted a series of experiments by determining the change in the permeability of water and oil before and after treatment with the composition of the reservoir models with different filtration characteristics, different water and oil saturation, assessed the extent the Yan desorption of water-repellent surface species during filtration of oil and water. After what has been estimated coefficients of the relative permeability of oil and water before and after processing a hydrophobic agent, the calculated degree (ratio) increase for oil and reduce water.

Example 3.In models of the reservoir as the porous medium used medium-grained quartz sand (0,140-0,315 mm). As a "dry" sand were calcined quartz sand; "initial wet" "dry" sand, through which was filtered one pore volume of water; "initial saturated" - "initial water-saturated sand through which was filtered one pore volume of oil; "residual oil" - "initial oil-saturated sand through which was filtered volume of water required to achieve full water coming from the reservoir model fluid.

To determine the relative permeability of the formation model measuring the transit time of each 20 ml (1 pore volume) of water or oil through the reservoir. The experiment is carried out at a residual pressure of 0.01 ATM (8 mm RT. Art.). Vacuum stop after the alignment phase boundary liquid-air interface liquid-breed.

A similar experiment was carried out on models of the formation after treatment of the inventive reagent

The calculation of the coefficients of permeability of oil and water before and after clicks the processing composition is made according to the law Darcy.

From the obtained data shows (table 2)that in the General case for all models of the reservoir there is a decrease in the relative permeability of water (up to 4 times) and a significant increase in the relative permeability to oil (up to 4 times).

It should also be noted that the pumping 30 pore volumes of water under laboratory conditions, the corresponding full to launder defensemen model of reservoir water, does not lead to desorption of hydrophobic agent from the surface of the breed, this can be judged by a constant rate of filtration of water through the formation model.

The results of the experiments are shown in the tables show that the composition effectively increases the permeability intervals with an initial saturation and thus practically does not reduce the productivity of high-permeability intervals with residual oil saturation, and the productivity of high-permeability intervals restored to original. The latter is important to extract residual oil is washed out and transported by water flow, and the better, the higher the filtration rate in the bottom hole zone of the well.

The use of the claimed composition can increase the permeability of oil at 3,750 times and lower permeability for water 4 times (see tab. 2).

Known hydrophobic powder in the hydrocarbon in the conditions reduce the permeability of high-permeability intervals, what hampers their effective development and can lead to lower final oil recovery.

The proposed hydrophobic composition can increase the permeability of oil up to 4 times and lower permeability for water up to 4 times (see table 2). Probably inevitable desorption of hydrophobic powder and, accordingly, the subsequent reduction of the hydrophobic effect is compensated by the presence of the CMEA, and the possible interaction of these components can achieve a higher hydrophobic effect than using them individually in the same concentrations. That is, the use of known hydrophobic powders together with CMEA allows you to extend the hydrophobic effect of the powder and to obtain the maximum effect.

In addition, the presence of the CMEA, highly adhesive, acid - and water-repellent properties, reduces corrosion of oilfield equipment. Used in the composition of the hydrophobic agent is cheaper known crasneanscki hydrophobic powders 20 times, which helps to reduce the cost of structures on the basis of hydrophobic powders, including by reducing their concentration in the solutions.

Table 1.

Evaluation of the actions of a hydrophobic agent, depending on its concentration in the organic races is varicela.
# exampleModel of capillaries filled with sand treated with the following compositions:The lifting height of the water in the capillary depending on the concentration of the agent, activated quartz sand, cmThe lifting height of the water in the capillary depending on concentration, on non-activated quartz sand, cm
2%1%0,5%0,1%0,05%2%1%0,5%0,1%0,05%
1CMEA in org. rest.00,50,51,01,501,01,21,51,7
2"POLYSIL"VDT*00,856,58,000,5246,0
3in gasoline01,06,07,09.01,752,53of 10.2514,0
4"Quartz"VDT*0 0,65,88,81100,72,56,09,0
5in gasoline00,96,09,31302,8a 3.911,915
6CMEA+"POLYSIL" (99:1)VDT*00001,90000,81,8
7in gasoline00002,1about000,72,3
8CMEA+"POLYSIL" (50:50)VDT*00002,00000,51,0
9in gasoline00002,20000,32,6
10CMEA+"POLYSIL" (1:99)VDT*000 1,60000,42,3
11in gasoline00001,70000,71,9
12CMEA+"Quartz" (99:1)VDT*00001,90000,62,4
13in gasolineabout0002,20000,42,5
14CMEA+"Quartz" (50:50)VDT*about0002,00000,22,1
15in gasolineabout0002,30000,82,6
16CMEA+"Quartz" (1:99)VDT*about0001,800 00,62,8
17in gasolineabout0002,10000,93,1
18Supervisory experience (raw sand)169
19Gasoline49
20dt2,54
*diesel fuel

The composition for treatment of bottom-hole formation zone, including hydrophobic powder in an organic solvent, characterized in that it further comprises a copolymer of ethylene and vinyl acetate in the following ratio, wt.%:

Hydrophobic powderof 0.05-2.5
A copolymer of ethylene with vinyl acetateof 0.05-10
Organic solventRest



 

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