SU711091A1 - Composition for preventing carbonate precipitation in oil field equipment - Google Patents

Description

The invention relates to formulations for the prevention of deposits and can be used to prevent the deposition of calcium, magnesium and barium carbonates in oilfield equipment.

In the process of extracting oil from watered wells, a significant amount of highly mineralized reservoir water supersaturated with calcium, magnesium or barium carbonates is extracted to the surface, which leads to the formation of carbonate deposits in the oilfield equipment.

An effective means of combating scaling in oilfield equipment is to prevent them with chemical reagents, scale inhibitors, which treat formation water.

Known composition based on inorganic phosphates and polyphosphator 1 formulations based on phosphonic acids, their salts or their composition 2.

However, these compounds have a number of significant drawbacks: phosphates show effect only at high concentrations, phosphonic acids

they are not available in sufficient quantities and, moreover, they are expensive and their use in the oil industry becomes economically inexpedient.

The closest in technical essence and the achieved result to the proposed VL. The composition is based on sodium hexametaphosphate (HMFN), which is used in the form of an aqueous solution for the treatment of wells at the rate of 4-5 mg of dry HMFN per 1 l of treated water 3.

 However, the use of this inhibitor does not stop the formation of deposits, but only slows down; during storage, the HMPH solution hydrolyzes and loses its inhibitory properties; inhibition efficiency does not exceed 30%.

The purpose of the invention is to increase the inhibition of scaling.

The purpose is achieved in that the known composition based on sodium hexametaphosphate additionally contains hydroxyethylidene diphosphonic acid.

(HEDP) in the following ratio of components, parts by weight:

Hexametaphosphate

rub 8.5-9.5

Hydroxyethylidene diphosphonic acid 0.5-1.5

The proposed composition is well soluble in water; possesses a syergic action and is almost 8 times cheaper than pure HEDP. In addition, in a dissolved state at room temperature, this composition for a long time practically does not lose its activity, while the 2% HMFN solution, when already, after 1 h, loses its effectiveness, by 27%.

It is advisable to use this composition in the amount of 1-10 mg / l of the treated water using known technological methods and equipment,. ,

Example 1 inhibition of scaling at 75-C compositions

from HEDP and GMPH in water of the following ionic composition, mg / l:

Sa “

525

& -r. 266

md

Sat / -108080

K-C1 15975

NSOd 280

A series of 250 ml flasks is placed in 100 ml of produced water and the inhibitor is added in such a quantity that its concentration in terms of 1 liter is respectively I, 5,10f20 ,, 100 MG-. Then the solutions are thermostatted at the temperature of the reservoir. The thermostatic control determines the content of calcium and magnesium ions in solution by the trilonometric method.

Comparative results to determine the effectiveness of the composition (HEDP and HMFN) and the known inhibitor are shown in Table 1.

Table 1

0.5 OEDf- + 9.5 GKFN

1, OEDS |) +9, O GMFF

1.5 HEDP +8.5 GMFN

2 HEDP + 8 GMFN

From the table it can be seen that the composition contains 0.5 vee. HEDP and 9.5 v.h., HIFN is the most valuable, as it has low cost and high efficiency at low dosages,

Pr m ime 2. Inhibition of scaling proposed composition

(from HEDP and HMPA) and the known composition of ionic composition on water, mg / l: Ca3 1233.2

.380

H-MA- -7500

SG14282.1

HCO378

The results are shown in table 2.

Claims (1)

Claim Composition for preventing carbonate deposits in oilfield equipment based on sodium hexametaphosphate, which is based on the fact that, in order to increase inhibition of scaling, it additionally contains hydroxyethylidene diphosphonic acid, in the following ratio, wt.h. Sodium hexametaphosphate 8.5-9.5 zq Oxyethylidene diphosphonic acid 0.5-1.5.