RU2242784C2 - System for distribution of inhibitor of hydro-forming among cluster wells - Google Patents

Abstract

FIELD: mechanical engineering.

SUBSTANCE: device has frame, supports, moveable and fixed stops with compacting elements, fixed stop is mounted on one of supports, moveable stop is mounted on another with possible displacement in direction of fixed stop and is provided with cylindrical frame for rotation covers, supported by prism, mounted on moveable support, one end of frame is made narrowing, other end is rigidly connected to moveable stop, while frame has dimensions, providing for free passing of it through tested pipe and through aperture of fixed stop with forming of enclosed hollow between frame and tested pipe with help from compacting elements, placed in moveable and fixed stops.

EFFECT: lesser laboriousness, simplified construction, higher effectiveness.

1 dwg

Description

The invention relates to techniques for control and regulation of technological processes and can be used in gas and gas condensate fields to prevent hydrate formation during gas production and prepare it for transportation due to the introduction of inhibitors.

In gas and gas condensate fields, the method of introducing hydrate formation inhibitors is widely used to prevent hydrate formation. Methyl alcohol, diethylene glycol, a solution of calcium chloride, etc. are used as inhibitors. The inhibitor is introduced into the gas stream to the place of possible hydrate formation (into the well, into the loop, separator, heat exchanger, etc.). In each case, the site of entry of the inhibitor is determined from the equilibrium hydrate formation conditions.

A well-known pumping system for the individual supply of an inhibitor of hydrate formation, when the inhibitor is supplied to each point by an individual dosing pump (Taranenko B.F., German V.T., Automatic control of gas production facilities. - M.: Nedra, 1976, p. 47-49).

An individual inhibitor pump circuit is cumbersome. The use of a large number of pumps requires significant operational costs. Operational experience shows that the reliability of pumps and valves is not high enough, stuffing box devices, safety valves, valves, etc. often fail.

There is also a system of centralized group supply and distribution of a hydrate inhibitor (Taranenko BF, German VT Automatic control of gas production facilities. - M .: Nedra, 1976, p. 49-50, 76-78). The hydrate inhibitor from the supply tank through the filter enters the pump. The pump feeds the inhibitor into a common reservoir. Then, using special automatic devices (flow regulators), the inhibitor is distributed at the input points. The system allows you to enter the inhibitor at various points of several technological installations of the field. When an inhibitor is introduced into plumes from gas well clusters, the inhibitor flow rate for each supply line is maintained in accordance with the gas flow in the corresponding loop from gas well clusters.

The disadvantage of the system is its low reliability, due to the fact that when a hydrate inhibitor is introduced at the mouth of gas wells in a well, the system does not provide control of the inhibitor flow rate for each well in the well depending on the gas flow for each well in the well.

The problem achieved by the invention is to create such a technical solution, using which would ensure the reliability of the system at the minimum required cost of an inhibitor for each well of the bush.

To achieve the technical result, the proposed hydrate inhibitor distribution system for the wells in the cluster contains a gas well cluster connected to a loop with a controllable control valve at the loop outlet, a centralized inhibitor inlet pump, an inhibitor flow regulator, and an inhibitor inlet line.

Distinctive features are that the system is additionally equipped with automatic dispensers and check valves installed sequentially along the inhibitor in the supply line at the mouth of each well of the bush, while at each well of the bush a safety valve is installed, connected through the throttle and check valve to the supply line of the inhibitor before automatic dispenser.

Automatic dispenser contains a plunger connected to the membrane, a thin washer (diaphragm), as well as an emphasis and springs located in the dispenser housing.

Thanks to the use of such essential features, it becomes possible to increase the reliability of the system when introducing the minimum required amount of inhibitor into each well in the bush, depending on the gas flow through this well in the bush during gas production and preparation for transportation

The present invention is shown in the drawing, which shows a diagram of the distribution system of a hydrate inhibitor in the wells of a cluster, consisting of two wells.

The system contains gas wells 1 of the bush, connected to the loop 2 with a controlled control valve 3 at the loop outlet, sequentially connected pump 4 and inhibitor 5 flow regulator installed in the supply line of the inhibitor 6 to the wells of the bush, as well as automatic dispensers 7 and check valves 8, established sequentially along the flow of the inhibitor to the mouth of each well of the bush. At each well in the bush, a safety valve 9 is installed, connected through an orifice 10 and a check valve 11 with an inhibitor line in front of the automatic dispenser. The automatic dispenser comprises a plunger 12 connected to the membrane 13, a thin washer 14 (diaphragm), a stop 15 and springs 16 located in the housing 17. The safety valve includes a plunger 18, a stop 19 and a spring 20 located in the housing 21.

The system operates as follows.

The inhibitor pump 4 is fed to the flow regulator of the inhibitor 5 and then through the supply line of the inhibitor 6 with a flow rate that prevents hydrate formation in the loop 2 with the corresponding gas flow rate, through automatic dispensers 7 and check valves 8 at the mouth of each gas well 1 of the bush. Moreover, each automatic dispenser 7 focusing 15 and the springs 16 is adjusted to the flow rate, providing a non-hydrate mode of operation of this well with the corresponding gas flow from this well of the bush.

With an increase in gas flow through the control valve 3 from the wells 1 of the bush and, accordingly, the flow of the hydrate inhibitor through the regulator 5, the gas pressure in the loop 2 and in the wells 1 of the bush will decrease, and the pressure drop across the membranes 13 of the automatic dispensers 7 will increase. Moreover, the regulating plungers 12, moving up, reduce the resistance of the washers 14, i.e. increase the flow rate of the hydrate inhibitor in accordance with the flow rate of gas from the corresponding wells 1 of the bush. The positions of the plungers 12 are determined by the efforts of the springs 16 and the pressure drops on the respective membranes 13.

With a decrease in gas flow through the control valve 3 from the wells 1 of the bush and, accordingly, the flow of the hydrate inhibitor through the regulator 5, the gas pressure in the loop 2 and in the wells 1 of the bush will increase, and the pressure drop across the membranes 13 of the automatic dispensers 7 will decrease. At the same time, the regulating plungers 12, moving downward, increase the resistance of the washers 14, i.e. reduce the flow rate of the hydrate inhibitor in accordance with the flow rate of gas from the corresponding wells 1 of the bush.

The limits of regulation of gas flow through a cluster of gas wells, as a rule (according to geological characteristics) are ± 20% of the nominal flow, i.e. Q _min ≈ 0.8Q _nom , Q _max ≈ 1.2Q _nom . Thus, the gas pressure at the wellhead 1 corresponding to Q _min is a well-defined value P _max , above which, in the non-hydrated mode of operation, the gas pressure in the loop 2 cannot rise. If the gas pressure in the loop 2 from the wellbore 1 increases independently of the gas flow rate, then this indicates that hydrates formed in the loop 2.

When the gas pressure in the loop 2 and in the wells 1 of the bush increases above P _{max, the} plungers 18 of the safety valves 9 under the action of gas pressure in the wells 1, overcoming the spring force 20 corresponding to P _max , move upward, opening the passage to the hydration inhibitor from the inhibitor supply line 6 to loop 2 with maximum flow.

After the hydrates are eliminated, the pressure in the loop 2 will decrease and the plungers 18 of the valves 9 under the action of the force of the springs 20, overcoming the gas pressure in the wells 1 of the bush, will move down and block the passage to the hydrate inhibitor from the supply line of the inhibitor 6 to the loop 2.

Claims (1)

A distribution system for a hydrate inhibitor in wells of a well containing a well of gas wells connected to a loop with a controllable control valve at the loop outlet, a centralized inhibitor inlet pump, an inhibitor flow regulator and inhibitor inlet line, automatic dispensers and check valves installed sequentially along the inhibitor in line supply at the mouth of each well of the bush, characterized in that on each well of the bush a safety valve is installed, connected through a throttle and ny valve supply line inhibitor prior automatic dispenser, and the automatic dispenser comprises a plunger connected to the diaphragm, a thin washer (diaphragm), and the abutment and the spring housed in the dispenser housing.