RU2429341C1 - Well flushing method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: well flushing method involves flushing with water solution of mixture of neonols AF₉-12 and AF₉-6; ratio of neonols AF₉-12 and AF₉-6 in mixture is 1:(4.5-5.5) respectively; water solution of mixture of neonols of 4.5-5.5% concentration is used; samples of asphalt-resin-paraffin deposits are pre-removed from the well and samples with undisturbed structure are taken; samples are built up on metal plates, submerged into the above solution and swelling time of samples by spectrophotometry method to balanced condition and the formation time of particles with asphalt-resin-paraffin deposits of minimum sizes in the flow of the above solution is determined, and bath of the above solution is arranged before flushing in the well; minimum time of bath is accepted equal to swelling time of samples to balanced state, and maximum time - during the formation period of time of particles with minimum sizes of asphalt-resin-paraffin deposits in flow of the above solution.

EFFECT: increasing well flushing efficiency.

3 ex, 1 tbl, 1 dwg

Description

The invention relates to the oil industry and may find application in flushing a well.

Known detergent composition for metal and painted surfaces, containing (parts by weight) of ethoxylated isononylphenol with a degree of hydroxyethylation of 12-neonol AF ₉ -12 1, ethoxylated of isononylphenol with a degree of hydroxyethylation of 6-neonol AF ₉ -6 0.5-1, sodium tripolyphosphate 0.1-2, sodium sulfate 0.1-2, water 8.3-2500. The composition is used in the form of an aqueous solution. (RF patent No. 2041258, publ. 08/09/1995).

Known detergent for cleaning a metal surface contains, wt.%: Ethoxylated monononylphenols based on propylene trimer neonol AF ₉ -12 3-4; neonol AF ₉ -6 3-4; soda ash 29-45; trisodium phosphate 15-25; sodium tripolyphosphate up to 100. The detergent is used in the form of an aqueous solution. (RF patent No. 2041927, publ. 08/20/1995 - prototype).

A disadvantage of the known technical solutions is the insufficiently high efficiency of flushing the well.

The proposed method solves the problem of increasing the efficiency of flushing the well.

The problem is solved in that in the method of washing a well, comprising washing an aqueous solution of a mixture of neonols AF ₉ -12 and AF ₉ -6, according to the invention, in the mixture, the ratio of neonols AF ₉ -12 and AF ₉ -6 is set to 1: (4.5-5 , 5) respectively, an aqueous solution of a mixture of neonols is used at 4.5-5.5% concentration, samples of asphalt-resin-paraffin deposits are preliminarily extracted from the well and samples with undisturbed structure are isolated, samples are deposited onto metal plates, immersed in said solution and determined by spectrophotometry time nab sample shaking to an equilibrium state and the time of formation of particles in the stream of said solution with minimum sizes of asphalt-resin-paraffin deposits, and before washing in the well, a bath of said solution is organized, the duration of the bath is minimally equal to the time of swelling of the samples to equilibrium, and as much as possible during the formation time in the stream said solution of particles with minimal sizes of asphalt-resin-paraffin deposits.

SUMMARY OF THE INVENTION

When flushing a well that has been sedimented by an ARPD, there is a danger of either not getting enough deposits, or blocking pipes and valves at the wellhead with large particles of exfoliating sediments. Known technical solutions do not solve these issues, because oriented only to the dissolution of sediments. As a result, the flushing efficiency of the well is low. The proposed method solves the problem of increasing the efficiency of flushing the well. The problem is solved as follows.

The ratio of neonols and the concentration of the solution are chosen. Carried out a series of experiments in launder AFS at ratios neonols ₉ AF AF -6 to -12 ₉ from 1 to 10 and 10 to 1. As a basic recording efficiency of washing AFS method used spectrophotometry. The optical density of the washing solutions was measured on an SF-102 spectrophotometer at a wavelength of 540 nm. ASPO samples are extracted from the well and samples with an undisturbed structure are isolated. Samples are deposited on metal plates without destroying the structure, immersed in the said solution and the turbidity of the solution is determined by spectrophotometry. The degree of turbidity of the ARPD is directly related to the degree of turbidity of the solution. The results are tabulated.

Build a graph of the dependence of the light absorption coefficient of the solution on time (figure 1). The graph shows the dynamics of the transmittance (CSP), where line 1 corresponds to the change in CSP at a ratio of AF ₉ -6 to AF ₉ -12 5 to 1, line 2, 3, 4, 5, 6, 7, 8, 9, 10 - accordingly, the ratios of AF ₉ -6 to AF ₉ -12 are 4 to 1, 3 to 1, 2 to 1, 1 to 1, 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 7. As can be seen from the graph, the greatest washing effect was achieved when the ratio of AF ₉ -12 to AF ₉ -6 as 1 to 5. Since the technical result is achieved when the ratio of the components is within 1: (4.5-5.5), then this ratio is accepted as claimed.

Figure 1 marks the time when the light absorption coefficient practically ceases to change, which indicates the maximum swelling of the deposits. On the graph on curve 1 is 2 hours. This time is considered the minimum for technological exposure of the well in the bath mode. Next, the samples in turn at intervals of time are exposed to the flow of the solution and under the microscope determine the particle size of the sediments into which the sediment layer breaks up. It is noted that with increasing exposure time, the particle size increases, which is undesirable. Since they always strive to minimize the particle size of leachable deposits to the minimum, they select the optimal bath time when the deposits are swollen and can deteriorate and when the particles of deposits form a small size when flushing, when they are able to pass through pipes and shutoff valves of the wellhead without creating a plug there, clog pipes. If the swelling time coincides with the optimal time to minimize the particle size when flushing the well, then it is taken as the most optimal.

Thus, when washing the wells using 4.5-5.5% aqueous solution of a mixture neonol ₉ AF AF neonol -12 and -6 ₉ at a mixing ratio of ₉ -12 neonols AF and AF ₉ -6 1: (4 5-5.5), respectively. As preliminary studies have shown, such a solution with such a ratio of neonols and such a concentration is most effective when flushing a well.

During operations, the well is filled with a washing solution, i.e. 4.5-5.5% aqueous mixture neonol ₉ AF AF neonol -12 and -6 ₉ at a mixing ratio of ₉ -12 neonols AF and AF ₉ -6 1: (4.5-5.5), respectively , hold technological exposure to swell the paraffin and the possibility of being washed out by the flow of the solution and wash the well with the same solution until the well is completely free of paraffin.

As a result, it is possible to wash the well from paraffin.

Case Studies

Example 1. Flushing an oil well from a paraffin deposit. It is determined that the swelling time of the AFS samples to an equilibrium state in a 4.5% aqueous solution of a mixture of neonol AF ₉ -12 and neonol AF ₉ -6 with a ratio in the mixture of neonols AF ₉ -12 and AF ₉ -6 1: 4,5 respectively, 2.3 hours. It is determined that the time of formation of sediment particles with a minimum size of up to 0.5 mm when flushing a well with the same solution is also 2.3 hours, i.e. coincides with the swelling time. This time is taken as optimal for the duration of the bath. The well is filled with a 4.5% aqueous solution of a mixture of neonol AF ₉ -12 and neonol AF ₉ -6 with a ratio in the mixture of neonols AF ₉ -12 and AF ₉ -6 1: 4,5, respectively, the process is held in bath mode for paraffin swelling and the possibility of being washed out by the flow of the solution for 2, 3 hours and flush the well with the same solution until the well is completely free of paraffin.

Example 2. Flush the oil well from the paraffin. Determine that the time of swelling AFS specimens equilibrated in a 5% aqueous solution mixture neonol ₉ AF AF neonol -12 and -6 ₉ at a mixing ratio of ₉ -12 neonols AF and AF ₉ -6 1: 5, respectively is 1, 7 hours It is determined that the time of formation of sediment particles with a minimum size of up to 0.5 mm when washing a well with a stream of the same solution is 2 hours. A time of 2 hours is taken as optimal for the duration of the bath. The well is filled with a 5% aqueous solution of a mixture of neonol AF ₉ -12 and neonol AF ₉ -6 with a ratio in the mixture of neonols AF ₉ -12 and AF ₉ -6 1: 5, respectively, technological exposure is carried out in the bath mode for swelling of the ARPD and the ability to be washed out by the flow of the solution for 2 hours and flush the well with the same solution until the well is completely free of paraffin.

Example 3. Flush the oil well from the paraffin. Determine that the time of swelling AFS equilibrated samples in a mixture of 5.5% aqueous solution neonol ₉ AF AF neonol -12 and -6 ₉ at a mixing ratio of ₉ -12 neonols AF and AF ₉ -6 1: 5.5 respectively 1.8 hours. It is determined that the time of formation of sediment particles with a minimum size of up to 0.5 mm when washing a well with a stream of the same solution is 1.9 hours. A time of 1.8 hours is taken as optimal for the duration of the bath. The well is filled with a 5.5% aqueous solution of a mixture of neonol AF ₉ -12 and neonol AF ₉ -6 with a ratio in the mixture of neonols AF ₉ -12 and AF ₉ -6 1: 5.5, respectively, the process is held in the bath mode for paraffin swelling and the possibility of being washed out by the flow of the solution for 1.8 hours and the well is washed with the same solution until the well is completely free of paraffin.

As a result, according to examples 1-3, it is possible to completely wash the well from ASPO. The use of the composition of the prototype showed a low washing ability and the presence of ARPD residues in the well after washing.

The application of the proposed method will solve the problem of increasing the efficiency of flushing the well.

Claims (1)

Method washing wells comprising washing the aqueous mixture neonols ₉ AF AF ₉ -12 and -6, characterized in that the mixture ratio neonols ₉ AF AF ₉ -12 and -6 is set 1: (4.5-5.5), respectively , an aqueous solution of a mixture of neonols is used at a concentration of 4.5-5.5%, samples of asphalt-resin-paraffin deposits are preliminarily removed from the well and samples with an undisturbed structure are isolated, samples are deposited onto metal plates, immersed in the solution, and the time of swelling of the samples is determined by spectrophotometry to equal the state and time of formation of particles in the stream of said solution with minimum sizes of asphalt-resin-paraffin deposits, and before washing in the well, a bath of said solution is organized, the duration of the bath is minimally taken equal to the swelling time of the samples to an equilibrium state, and maximally during the time of formation of particles in the stream of said solution with minimal dimensions of asphalt-resin-paraffin deposits.

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