RU2368759C2 - Wellhead equipment - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention refers to oil production, and namely to wellhead equipment. It consists of a casing head with side taps, which rests upon the pipe hanger with side taps, and the device for relieving pressure from the tube space. The device meant for relieving pressure from the tube space is a jet pump installed in the tube hanger tap. The suction of the jet pump is connected with the nozzle to the casing head cavity and to the annular space between the production casing and the flow column. The assembly for separate throttling of water and gas and for warming the flow being pumped is installed on the nozzle before the jet pump suction.

EFFECT: providing gas extraction and pressure relief from the tube space; when the flow is warmed, reliability of the wellhead equipment is increased.

1 dwg, 2 cl

Description

The invention relates to oil production, in particular to equipment wellhead for oil and gas production. The main purpose of wellhead equipment is the suspension of pumping pipes, the direction of well production in the flow line and the provision of gas extraction from the annulus.

Wellhead valves are known, the device for discharging gas from the annulus of which is made in the form of a valve of complex design with moving sleeves and two locking elements.

Their disadvantages are unreliability of work and frequent cases of freezing in the winter. Closest to the claimed invention is No. 2242583, selected as a prototype, in which the device for relieving pressure from the annulus is made in the form of a venturi installed in the outlet of the pipe suspension and communicating with the reduced pressure zone with a column head.

Its disadvantages are the achievement of only a certain decrease in pressure in the annulus and the inefficiency of freezing in the winter.

The aim of the invention is to increase the reliability of wellhead reinforcement, a complete decrease in gas pressure in the annulus, prevention of conditions for hydrate formation, an increase in oil flow into the well, and elimination of the possibility of equipment freezing in winter.

In solving the technical problem, the effect of creating a vacuum by jet pumps (ejectors) and the effects of heat generation during the throttling of liquids through local hydraulic resistances and during the throttling of gases (throttle-Joule-Thomson effect) are used.

It is known that a jet pump with a freely falling stream of water is capable of creating a vacuum of up to 100 mm Hg. Therefore, the use of a jet pump in the design of wellhead valves allows you to eliminate the complications during the operation of wells by creating the necessary effects when pumping a gas-liquid stream. When throttling liquids creates a thermal effect, which is determined by the formula:

Where

коэффициент восстановления;

recovery factor;

- критерий Прандтля;

- Prandtl criterion;

µ - dynamic viscosity, Pa · sec;

ρ, ρ ₁₅ - density, kg / m ³ ;

C is the heat capacity of oil, J / kg ° C;

t is the working temperature of the oil before the throttling process;

ΔР - throttle pressure value, Pa.

λ _n = 0.14; µ = 0.01 ÷ 0.07; ρ = 1000; ρ ₁₅ = 700; C = 2000.

When throttling gases, the Joule-Thomson effect is observed, which consists in a change in the temperature of the gases as they expand. Experiments show that at sufficiently high pressures, all gases give a negative Joule-Thomson effect, i.e. heat up. Petroleum gas up to 90% consists of methane, and if certain conditions are met, it will have a negative effect.

Denote the pressure, volume and potential energy of the gas before throttling - P ₁ , V ₁ , U ₁ , after throttling - P ₂ , V ₂ , U ₂ . "Typically, when throttling a real gas P ₁ V _l -P ₂ V ₂ > 0 and U ₂ -U ₂ > 0, the work of pushing the gas leads to an increase in internal energy. Under conditions where the push work is greater than the increase in internal potential energy ΔU _nom , its excess goes to increase the internal kinetic energy ΔU _kin , the gas temperature rises (dT> 0) "(Thermotechnics, V.N. Lukanin., M.G. Shatrov and others. Textbook for universities. M: Higher school, 2005 p. 127).

The invention is illustrated in the drawing, which shows a diagram of a wellhead wellhead.

Wellhead fittings are installed on the production casing and comprise a flange pipe head 1 with a lateral outlet 2 and a flange pipe suspension with a lateral outlet 4. The pipe suspension 3 is supported by the pipe head 1 and is attached to it as a flange connection. In the outlet 4 of the pipe suspension 3, a jet pump 5 is installed, the intake of which is connected to the pipe 6, which is connected to the cavity of the column of the head 1, and therefore to the annular annular space 8 formed by the production string 9 and the tubing string 10. During operation oil enters the well through the tubing string 10, and through outlet 4 it enters from the bottom of the well to the surface in the oilfield prefabricated reservoir. The jet pump 5 installed in the outlet 4 of the pipe suspension 3 provides gas extraction and gas pressure reduction in the annular space 8, which reduces the back pressure on the reservoir and increases the flow of oil to the well, increasing its productivity.

On the pipe 6 additionally installed node 7, which is a structure of three devices. The first serves to swirl the flow, in which, under the action of centrifugal forces, moisture droplets are collected around the perimeter and are pumped through the throttle openings of the second device using the jet pump 5 through the throttle openings to the flow line. Dry gas is pumped out through a third device located in the center of unit 7. When throttling liquid and dry gas, a heat release effect occurs that contributes to reliable operation of wellhead valves in winter.

When working in the summer period or when there is no need to heat the oil flow in order to increase oil flow, wellhead fittings can be used without unit 7, which improves well productivity.

Claims (2)

1. Wellhead fittings containing a pipe head mounted on the production casing with bends, a pipe suspension with bends resting on it and a device for relieving pressure from the annulus, characterized in that the device for relieving pressure from the annulus is made in the form of a pipe suspension of the jet pump, the reception of which is connected to the cavity of the column suspension. 2. Wellhead wellbore according to claim 1, characterized in that it further provides a device for separate throttling of water and gas in order to obtain heat against freezing of equipment.

Images