SU789434A1 - Method of preventing inorganic salt deposit formation - Google Patents

Description

(54) METHOD FOR PREVENTING THE DEPOSITION OF INORGANIC SALET

The invention relates to methods for preventing the deposition of inorganic salts in wells and oilfield collection and transportation systems. Methods are known for preventing the deposition of inorganic salts during the production, gathering and transportation of flooded oil by treating it and bottom-hole with scale inhibitors. Such inhibitors include: polyphosphates, organic phosphates, phosphonates, sulfonic acid salts, alkyl and aryl sulfonates, l and 2. The disadvantages of the known methods are a significant consumption of a scale inhibitor, low protective effect, instability in the region of elevated temperatures, the formation of precipitation in the preparation of initial solutions with saline stratum waters. The closest to the proposed technical essence and the achieved result is a method of preventing the deposition of inorganic salts during the extraction, gathering and transportation of flooded oil by introducing organophosphorus compounds into the reservoir or into the bottomhole zone under pressure. According to this method, compounds of ethylenediamine-N, N, N, N -tetramethylphosphonic acid or N- (2-oxyethyl) ethylenediamino-, N, N, N-trimethylenephosphonic acid are used as a scale inhibitor, in an amount of 0.00030, -0005 weight .% of the water extracted with the oil W. J. The disadvantage of this method is the low efficiency of the method and the significant consumption of a scale inhibitor. The purpose of the invention is to reduce the intensity of deposition of inorganic salts and reduce the consumption of inhibitor. This goal is achieved by injecting organophosphorus compounds of 1,3-dig1minopropanal-2 derivatives of the following structure (H ,,) into the reservoir or into the bottomhole zone (H ,,) .- N-CH CH-CH, j-Nj-CH.jPOjH. j OH CH where

The method is carried out in the following manner.

Pre-prepared aqueous solution of the reagent with a concentration of 0.5-1 wt.% Using a dosing pump or using a dosing device is fed into the fluid flow at a rate of 0.0001-0,0003 wt.% Relative to water, calculated as net output. j agent. The reagent is fed to the production well and the waterflood system through injection wells to process the entire reservoir, as well as to the oil collection and transportation system. The place of supply of the reagent is chosen, depending on the technological and economic feasibility for the conditions of a particular field.

After the inhibitor has been injected, a stabilizing effect is determined, periodically 1 sampling is performed to determine the calcium sulfate concentration at a given time. Protective From the above data, it follows that the proposed method for preventing the salt deposition of inorganic salts significantly exceeds the known technical solution in terms of reducing the intensity of failures. When the concentration of the inhibitor is in a known way equal to 0.0003 wt.%, After 240 hours the protective effect is 64.1%, whereas at a given concentration in the proposed method, the protective effect is 85.4%, while to achieve a protective effect

the inhibition effect is determined by the formula

G - p .100 (%)

Co de E protective effect of inhibition. (%) With an initial calcium sulfate concentration (g / l):

C. calcium sulphate concentration at a given time without the addition of an inhibitor (g / l); C is the calcium sulfate concentration at a given time with the addition of an inhibitor.

The obtained comparative data on the evaluation of the effect of preventing the deposits supersaturated with calcium sulfate solution according to the known and proposed methods are given in the table. The concentration of calcium sulfate in all experiments was 7 g / l. equal to the effect in a known method, it is necessary to introduce 0.0002 weight,% inhibitor, into the solution. Thus, the use of the proposed method allows to increase the efficiency of the method and reduce the consumption of the inhibitor injected. The expected economic effect from the introduction of this invention only in the system of enterprises of the association Orenburgneft will be not less than 95-100 thousand rubles. S year.

Claims (3)

1. Method of preventing inorganic salt deposition during production, discharging and transportation of watered oil by introducing organophosphorus compounds into the reservoir or in the bottomhole zone under pressure, distinguishing I with the fact that, in order to reduce the intensity of salt deposition, as organophosphorus compounds use 1,3-diaminopropanol-2 derivatives of the following structure (H OjPCHj), - 9H-CH, j -N -CH2POjH.,, but HE One where. 2. A method according to claim 1, characterized in that the organophosphorus compound is introduced in an amount of 0.0001-0,0003 wt.%. Sources of information taken into account in the examination 1. Himatudinov Sh. N. Reference book on oil production. M., Nedra, o 1974, p. 613. 2. and Gas J. 1968, 15/1, V 66, No. 3, p. 88-89; 92-93. 3. USSR author's certificate five No. 541973, cl. E 21 B 43/12, published 01/05/07.