SU855335A1 - Method of transporting high-viscous water-oil emulsion - Google Patents

Description

(54) METHOD OF TRANSPORTATION OF HIGH-VISIBLE WATER-OIL EMULSION

one

The invention relates to the oil industry, in particular to the transportation of highly viscous coal-bearing oils from the upper horizons, containing their water.

Oil emulsions of the upper horizons have increased viscosities of up to 30-50 pz, and the phase inversion point, upon reaching which a further increase in water cut leads to a decrease in the viscosity of the mixture, is shifted up to 80% watering. Therefore, in flow lines from Wellheads to group metering units, as well as in prefabricated reservoirs, there is a high level of hydraulic losses.

There is a known method of transporting high viscosity oils containing water by adding additional water and imparting rotational motion to the flow. The rotation of the flow is provided by pipes on the inner surface of which there is a screw thread 1.

However, this method of transportation has the disadvantage of making screw cuts on the inner surface of an oil country tubular pipe.

There is also known a method of transporting highly viscous water-oil emulsions through intrafield pipelines, according to which the oil and gas supply to the mixture enters the booster gas pumping station, where it is degassed, and the water and oil that separates into the boulete are pumped out through a single pipeline to the oil treatment plant 2.

When water and oil are jointly transported from the DNS boils to the oil treatment plant, intensive movement of water and oil occurs, resulting in a stable emulsion that does not collapse during further pumping and is dehydrated only at increased costs of the emulsifier and heat. And the water content in the oil increases the effective viscosity of the emulsion. High emulsion viscosity leads to increased hydraulic losses

20 in the pipeline and, consequently, to the need to increase the pumping pressure, resulting in an increase in energy and material costs, as well as

increased metal consumption due to the need to increase the thickness of the walls of the pipeline.

The purpose of the invention is to reduce the level of hydraulic losses during transportation of highly viscous oil-water emulsions by preventing the formation of a water-in-oil emulsion.

This goal is achieved in that the partially dewatered oil and the separating water are taken from the separation apparatus alternately, and pumped through the pipeline successively in separate phases.

In this case, partial dehydration of the oil before transportation to the preparation unit reduces the concentration of water dispersed in it, and, consequently, effective viscosity, which leads to a decrease in the hydraulic resistance coefficient. Filling the pipeline with separate phases reduces the pressure drop between the starting and ending points of the pipeline, since friction losses along the length of the pipeline decrease in proportion to the total length of water plugs, which reduce the contact area of high viscosity oil with the inner surface of the pipeline. In addition, the cork flow structure allows the main part of the reservoir water to be separated at the preliminary discharge stage without overloading the oil preparation unit with highly watered emulsion.

The drawing shows a schematic diagram of the proposed method.

The method is carried out as follows.

The oil and gas outlet for the mixture from the group metering units 1 enters the bulit 2 bottom, where gas separation and partial separation of water and oil are carried out. From the bulite 2 separated water and partially dehydrated oil by pump 3 through, switching device 4 is alternately taken and pumped through pipeline 5 successively in separate phases to the oil treatment installation 6.

An example. An oil and gas mixture in the amount of 3841 m per day with a water content of up to 52%, dynamic viscosity at 6 ° C fi 12 pz, processed with a deaerator emulsifier at the rate of 25 g per ton of liquid, is collected in two bulits 2 DNS of 200 nd each. The gas-oil mixture is separated on the DNS.

Analysis of laboratory studies of oil samples taken over the cross section of the bulites, with

the steady state of their operation shows that 35% of the total volume of water is in a free state. Partially dehydrated oil with a viscosity of 3.8 pz and separated water is taken by pump 3 alternately for 50 and 10 minutes, respectively, and simultaneously pumped through one pipeline 5 to the oil treatment plant 6. The capacity of the pumping units is 165 m. Alternate phase selection during a set time is provided automatically by means of a diaphragm switching valve. At the same time, the pumping pressure decreases to 13.5 ati against 20.2 ati when pumping a water-oil emulsion with ordinary

in a way.

The sequential selection of phases separated in the bottom of the bulits and their successive transportation through a single pipeline to the oil treatment installations makes it possible, by reducing the viscosity of the emulsion, to reduce the hydraulic resistance in the pipelines. The oil transfer pressure decreases on average by B-8 MPa, which reduces the energy and material costs associated with transportation

of oil.

Claims (2)

1. Tugunov, p. I. and Novoselov, V.F. Transportation of oil and petroleum products through pipelines. M, “Nedra, 1973, p. 8-11. 2. Abstract scientific and technical collection “Oilfield business, Moscow, VNIIOENG, № 3, 1976, p. 14. vm mt