RU2354677C1 - Method of preparing flushing solutions on oil base for pumping into well - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: in method of preparing flushing solutions on oil base for pumping into well including introduction of liquid hydrocarbon slurry oil into oil products as hydrocarbon slurry oil there is used oil paraffin dissolvent at amount of 5-20 volume % with addition of synthetic rubber SCD-N at amount of 0.01-0.05 wt %.

EFFECT: increased efficiency of pumping flush solutions on oil base through flow string at repair operations at well and at transporting oil of high viscosity via pipeline by means of reducing hydraulic resistance due to simultaneous reduction of fluid viscosity and turbulence.

1 ex, 2 tbl

Description

The invention relates to methods for preparing a hydrocarbon-based process fluid for pumping through a pipe string during repair work at a well and can be used for transporting high-viscosity oil through a pipeline.

A known method of preparing a fluid that helps to reduce the hydraulic resistance that occurs when it is pumped, carried out by dissolving in this fluid small amounts of high molecular weight polymers [Artyushkov L.S. Dynamics of non-Newtonian fluids. - L .: LKI, 1979]. The disadvantage of this method is that the reduction in hydraulic resistance is achieved only by reducing turbulence when pumping fluid, at the same time, the viscosity of the latter does not decrease, and in the laminar regime of fluid motion, hydraulic resistance will not decrease.

The closest solution is a method of preparing highly viscous oil for transportation through a pipeline, which consists in introducing low-viscosity hydrocarbon diluents into oil, for example, adding liquid products of associated petroleum gas processing into oil [RF patent No. 2089778, IPC 6 F17D 1/16, publ. 09/10/97, Bull. No. 25].

A significant disadvantage of the method of preparing high-viscosity and paraffin oil for pipeline transportation, which consists in introducing low-viscosity hydrocarbon diluents into oil, is that when they are used, the hydraulic resistance of the oil flow is not reduced.

The technical task of the proposal is to increase the efficiency of pumping oil-based washing solutions through a pipe string during repair work on a well and during transportation of highly viscous oil through a pipeline due to a simultaneous decrease in fluid viscosity and a decrease in hydraulic resistance in a turbulent flow regime.

The problem is solved by the method of preparation of oil-based washing solutions for injection into the well, which includes the introduction of a liquid hydrocarbon diluent into oil products.

New is that as a hydrocarbon diluent use a solvent of petroleum paraffins in an amount of 5-20 vol.% With the addition of synthetic rubber SKD-N in an amount of 0.01-0.05 wt.%.

The petroleum paraffin solvent (RPN) is produced according to TU 0251-062-00151638-2006, is a yellow to black liquid, is produced by the workshop unit during the oil preparation process and is the gasoline fraction released by the rectification or separation of oil, followed by the addition of stable oil to amount up to 5% by volume. It is used as a paraffin solvent for flushing oil wells.

SKD-N corresponds to TU 2294-100-05766801-2003 and is a synthetic cis-butadiene (SKD) neodymium rubber (N), which is the product of the polymerization of butadiene or butadiene with isoprene in an aliphatic hydrocarbon medium in the presence of a catalytic system based on neodymium compounds. Designed for use in the tire and rubber industry and other sectors of the economy for the manufacture of industrial products. Its use as an anti-turbulent additive from literature available to authors is unknown.

Improving the transport properties of viscous oils can be achieved by mixing them with low-viscosity oils, liquefied gases or hydrocarbon diluents. These measures reduce the effective viscosity of the oil.

Laboratory tests to determine the conditional viscosity of oil containing on-load tap-changer and SKD-N were carried out using a VBR-1 funnel. Table 1 shows the results of studies of the viscosity of two oil samples containing 5-20 vol.% RPN and 0.01-0.05 wt.% SKD-N. Based on the data in the table, we can conclude that the addition of 5-20% RPN and 0.01-0.05 wt.% SKD-N in oil reduces its viscosity: from 9.6-28.8% low viscosity to 18.5- 60.7% for high viscosity oil.

The decrease in hydraulic resistance during the flow of hydrocarbon fluids through pipes in a turbulent mode can be achieved by additional dissolution of even small amounts of high molecular weight polymers. As a rule, it is enough to add 0.0001-0.01% polyisobutylene, polymethylmethacrylate, aluminum soaps of organic acids (for example, naphthenic) and other high molecular weight oil-soluble polymers and surfactants to the oil.

The practical importance of this effect for the oil industry lies in the possibility of multiple reductions in power costs in the turbulent mode of fluid movement through pipes, but there is no consensus in the literature about its nature. The most plausible point of view is the suppression of thickened wall layers of turbulent pulsations of a liquid. This is facilitated by the linear arrangement of long polymer chains along the wall, which also prevents the formation of random wall eddies, i.e. coagulation of fluid layers [Hoyt J.V. The effect of additives on the friction resistance in a liquid. // Theoretical foundations of engineering calculations. 1972, vol. 94, ser. D, No. 2, pp. 1-31].

An example of a specific application. Preparation of an oil-based wash solution and flushing a well using coiled tubing (flexible pipe). They collected 0.3 m ^{3 on-} load tap-changer (10 vol.%) Into the tanker, then 2.7 m ^{3 of} commercial oil was added to the same tanker and mixed. They brought the mixture to the well. Before launching the flexible pipe, the sensors (transducers) of the Panametrics PT 878 flowmeter were installed on the discharge line of the pump unit.

During the descent process, 3 m ^{3 of} commercial oil was pumped into the flexible pipe, while the following parameters were controlled: Panametrics PT 878 flowmeter - commercial oil flow rate, SIN-35 unit pressure gauge — injection pressure. During the descent of the flexible pipe after injection of marketable oil, the prepared mixture of oil and on-load tap-changer was pumped in a volume of 3 m ³ . After pumping the mixture in an amount equal to the volume of the “flexible pipe”, we started to control the washing parameters. Compared the injection parameters of commercial oil and commercial oil with 10 vol.% Solvent paraffins. When washing a well through a flexible pipe with commercial oil from 10 vol.% Solvent of paraffins, the oil flow rate increased by 24%, while the pressure on the unit decreased by 29% (table 2, p. 4).

A mixture of oil and 10 vol.% On-load tap-changer containing SKD-N synthetic rubber was pumped through a “flexible pipe” in order to simultaneously reduce the viscosity of the oil and reduce the hydraulic resistance of the liquid in the turbulent flow regime. In 2.7 ³ m oil, 0.3 m ^{3 on-} load tap-changer containing 100 g of synthetic rubber SKD-N (0.04 wt.% SKD-N in on-load tap-changer) was added. The results of measurements on the Panametrics PT 878 flow meter and SIN-35 unit pressure gauges, shown in Table 2, Clause 5, showed that the flow rate of the pumped solution increased by 30%, while the pressure on the unit decreased by 39%.

The results of flushing through a “flexible pipe” with oil with the addition of on-load tap-changer and synthetic rubber SKD-N are presented in table 2.

Thus, in this proposal, the result is achieved - the efficiency of transportation of highly viscous petroleum products and repair work is improved by simultaneously reducing the viscosity of oil and lowering the hydraulic resistance of the fluid in a turbulent flow regime.

The effectiveness of the method is achieved by adding a solvent of petroleum paraffins and SKD-N rubber to oil and petroleum products, which increases their passing ability when pumping through a pipeline or through a “flexible pipe”, while the paraffin solvent plays the role of a diluent and reduces the viscosity of oil and petroleum products, and SKD-N rubber additive helps to reduce hydraulic friction of oil in turbulent mode.

Table 1
Conventional viscosity of oil containing on-load tap-changer and SKD-N at 20 ° С The volume of oil,% Volume of on-load tap-changer,% Conventional viscosity of the original oil and oil with the addition of on-load tap-changer and SKD-N, s The decrease in viscosity of the composition relative to the initial viscosity of the oil,% Sample 1 one hundred 0 26 - 0 one hundred fifteen - 95 5 23.5 9.6 90 10 21,2 18.5 80 twenty 18.5 28.8 Sample 2 one hundred 0 105 - 0 one hundred fifteen - 95 5 79 24.8 90 10 56 46.7 80 twenty 45 57.1

table 2
The results of the use of solvent petroleum paraffins (RPN) and rubber SKD-N No. Type of process fluid with added additives Flushing Parameters Engine RPM Unit pressure, MPa Fluid flow rate, l / s one Commodity oil 700 22 0.8 1000 35 0.99 2 Commodity oil with 5 vol.% RPN 700 eighteen 0.9 1000 29th 1.05 3 Commodity oil with 5 vol.% On-load tap-changer and 0.05 wt.% SKD-N in on-load tap-changer 700 16 0.95 1000 27 1,1 four Commodity oil with 10 vol.% RPN 700 fifteen 1,08 1000 26 1.12 5 Commodity oil with 10 vol.% On-load tap-changer and 0.04 wt.% SKD-N in on-load tap-changer 700 13 1.15 1000 22 1.16 6 Commodity oil with 20 vol.% RPN 700 fourteen 1.13 1000 23 1.25 7 Commodity oil with 20% on-load tap-changer and 0.01 wt.% Solution of SKD-N in on-load tap-changer 700 fifteen 1.24 1000 25 1.43

Claims (1)

A method of preparing oil-based washing solutions for injection into a well, comprising introducing a liquid hydrocarbon diluent into oil products, characterized in that the hydrocarbon diluent is a solvent of petroleum paraffins in an amount of 5-20 vol.% With the addition of SKD-N synthetic rubber in an amount of 0 , 01-0.05 wt.%.