книги / Организация закачки воды. Система поддержания пластового давления

7. WATER DISTRIBUTING POINTS

According to their technical outfitting, water distributing points (WDP) are similar to pressure pipe header blocks; additional elements comprise the WDP heating equipment and I&ACS. In contrast to the pressure pipe header block, the WDP is located at a considerable distance from the BGPS and closer to the zone of concentrated location of a group of injection wells. In this case, the greatest economy in length of high-pressure pipelines is obtained. But even at ordinary arrangement of injection wells, construction of the WDP provides for a reduction of metal consumption, especially at a large number of wells connected to one

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group pumping station. In other words, it is expedient to construct the WDP under condition of relatively low injectability of the injection wells.

Usually one WDP is connected with four to six injection wells. The WDP room (6x6 or 6x9 m) houses shut-off slide valves and diaphragms with differential pressure gauges for measuring the flow rate of process liquid pumped into each injection well.

The WDP room, which is referred to explosion-hazard class B-16, is equipped with exhaust ventilation for airing the room prior to entry of the attending personnel. Electric heaters provide in winter time the temperature inside the room not below 5 ºC.

Injection wells

The wellhead of an injection well is provided with a standard equipment designed for a maximum pressure expected at injecting the process liquids. The wellhead equipment shall provide for the well sealing, installation of oil-well tubing, and for performance of such processes as injectability restoration, measurement of pressure and well injectability. The most frequently employed is the equipment, type 1АНЛ-60-200 or АН1-65-210 with a flow area of the Christmas-tree of 60 to 65 mm at a working pressure of 20 MPa.

From the group pumping station, water is fed through a flow tee of the wellhead equipment into the oil-well tubing, and a neutral (buffer) liquid is fed through a pip of the flow cross into the annular space.

The parameters of oil-well tubing for injection wells shall be selected based on conditions of mechanical strength and permissible losses of head upon injecting the process liquid. The flow rate of process liquid being pumped into the injection well is regulated with a gate valve, such as type 1УР-50, with a nominal diameter of 50 mm designed for automatic regulation of flow rate within the limits from 50 to 1600 m3/day at a working pressure of up to 21 MPa.

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For measuring the flow rate, different types of flow meters may be used. So, the flow meter designed by Institute Giprotyumenneftegaz comprises a

РШ-4 ball-type transducer and a flow integrator, type ИТЖ-1 or ИРЖ-2.

Technical characteristics of the РШ-4 flow rate transducer mounted

Mass, kg ……………………………………………………… 47 Permissible content of mechanical admixture, g/l……………. 40 Permissible size of particles of mechanical admixtures, mm … 8

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