SU1752940A1 - Method of acid treatment of formation - Google Patents

Abstract

The invention relates to the oil industry, in particular to methods for treating wells to increase their productivity. The purpose of the invention is to reduce the corrosivity of the acid solution and to increase the efficiency of the method by increasing the depth of penetration of the acid into the formation. In the known method, which involves pumping a solution of hydrochloric acid into the formation, a permanent magnet is lowered before the acid solution is pumped into the well. 3 tabl „

Description

The invention relates to the oil industry, in particular to methods for treating wells to increase their productivity.

Methods are known for acid treatment of the wellbore zone using hydrochloric and other acids. However, the efficiency of their use in oil production for stimulating the operation of oil producing wells is low due to the shallow penetration of acid into the formation.

Closest to the present invention is a method of acidizing a well, which involves injecting hydrochloric acid solution into the formation, into which, before injection, a substance is introduced with F-positive heat of dissolution in an aqueous medium.

A disadvantage of the known method is high corrosive activi Ney.

availability of injected compositions and insufficient penetration of acid into the reservoir.

The purpose of the invention is to reduce the corrosivity of the acid solution and to increase the efficiency of the method by increasing the depth of penetration of the acid into the formation.

The goal is achieved by the fact that according to the method of acid treatment of a well, which involves injection of Kyo / Gothy solution into the formation, a permanent magnet is lowered into the well before injection of the acidic solution into the well.

The method is carried out as follows.

Acid is delivered to the wellhead in the acid tank. A magnet is lowered into the well and acid is pumped. At the end of the injection, the well is left to react with the acid with Yyroda. The% is then removed by peX products.

ABOUT

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--- En-ai & 2 & 52Јg # ё 1 and TSTSSSi5SEa.fci bjSS5- s.

ktsii and let the well into operation, I

To confirm the achievement of the objective of the invention: reducing the corrosivity of the injected acid solution, laboratory tests are carried out.

Iron cords are poured into two cages with (solution of acid. One of the tubes is spiked in a permanent magnet field with a magnetic field of 800A / m and 10% of mmonium is added to the other. Saline, nitrogen are used in the studies. and sulfuric acid. The resultants are listed in Table 1.

As can be seen from Table 1, the dissolution of metal in the bottles with a magnet more than 2.5 times goes slower than in the controls, which indicates a significant decrease in corrosivity.

To confirm the increase in the efficiency of the method by increasing the depth of penetration of the acid into the formation, the following tests are carried out. Compose-; reservoir model from cores of natural rocks. The carbonate content of the rocks is 0%. The physical parameters of the reservoir model are as follows: model length 2 cm, diameter 2.5 cm,. porosity 13% effective pore volume 25 cm.

Saturate the reservoir model with oil. Oil is filtered in a reservoir model at a constant pressure drop of 1.0 MPa and the initial permeability is determined. Then the model is processed using the proposed method, and 1.0 cm of 1% hydrochloric or nitric acid is injected in the presence of a permanent magnet with a constant volume flow rate of 2-10 cm3 / s. Under the same conditions, the effectiveness of a known method is checked. 1 cm of hydrochloric or nitric acid is added to the formation model with the addition of 100 mg of ammonium chloride.

The reaction time of the acid with the rock is controlled by gassing

in the process of filtering. The results of the study, the investigations are given in table 2. I

As can be seen from Table 2, the range of penetration of the acid into the formation by the proposed method is 3.5 times greater than that known.

Example. Well depth of m reveals oil saturated

the reservoir is in the range of 1810-1816 m. The collector is a limestone. The flow rate of the well over 10 years of operation has decreased from 1bO to 5 m5 / day. In the well installed on the pumping unit

5 weed tubes permanent magnet with a magnetic field strength of 800 A / m. The wellhead was equipped with a head and connected through communications to a pump connected to acid pumps with a total volume of hydrochloric acid solution of 6 m. Hydrochloric acid solution is injected into the reservoir. After the well treatment, the equipment is removed and the well is pumped over to remove the reaction products. Comparative data indicating the advantage of the proposed method compared with the known,

0 are given in table 3.

Thus, the application of the proposed method allows reducing the corrosivity of the acid and increasing its radius of penetration into

5 layer, which will increase the effectiveness of acid treatments and productivity of wells.

Formula of invention

A method of acidizing a well, which involves pumping an acid solution into a formation, different from the fact that, in order to reduce the corrosivity of an acidic solution and increase the efficiency of the method by increasing the depth of acid penetration into the formation, a permanent magnet is lowered before the acidic solution is pumped into the well. .

1752940

Table 3

Claims (1)

Claim A method of acid treatment of a well, including pumping an acid solution into the formation, characterized in that, in order to reduce the corrosion activity of the acid solution and increase the efficiency of the method by increasing the depth of acid penetration into the formation, a constant is lowered into the well before the acid solution is injected magnet. 5 1752940 That b L C 6 a 1 Time, Sample weight, in Dissolution min bukse, g hinges in boxe wt.% With magnesium The control- Tom naya (by With magnesium Cont famous Tom role-. way) naya Hydrochloric acid 0 0.4753 0.47893 0 0 55 0.46445. 0.46305 / 0.23 2,56 105 0.4639 0.4528 0.34 4.72 142 0.46365 0.44220 ‘ 0.40 6.94 4000 0.2985 0.0210 35.88 99.56 Nitric acid 0 0.4832 0.4871 0 0 60 0.4817 0.4734 0.31 2.81 105 0.4809 0.4626 0.48 5.03 142 0.4805 0.4515 0.56 7.31 4000 0.2962 0,0008 Sulfuric acid 38.70 99.84 0 0.4786 0.47931 0 0 .56 0.4774 0.4667 0.25 2.63 107 0.4769 0.4559 0.36 4.88 161 0.4766 . V 0.4552 0.42 7.12 4000 0.3057 0,00168 36.13 99.65 I table 2 Indicators Way Famous Proposed With hydrochloric acid Core length, cm 42 42 Core diameter, see 2.7 2.7 The initial porosity,% thirteen thirteen ^v Pore volume, cm ³ 25 25 The permeability of the original, mm ² ο, ονίο ’’ * oh ου to Permeability at the end 0, O32H0 ~ ^ experiment, mm ² o.pio The reaction time of the hydrochloric acid solution with 1134 doy min 307 ' Penetration range  · -; '/. solution of hydrochloric acid 6.2 J 22.8 slots in the breed, cm I <2/5 «Λ With nitric acid _______ 1023 20.7 ΐ · ΰ '· ί) j · / 1752940 -.8 Table 3 Indicators Way ——— g— Famous Proposed Well production, m ^? / day 'upon delivery at 100 '160 1 operation! before processing coy G after ob- 45 45 Ί 'work ^: Range of i solution 220 250 ipa hydrochloric acid per layer, m 2.9 3.0 Processing time, h 9.0 Additional 12.0 oil production for treatment account, m ³ / day 175.0 205