RU2608642C1 - Method of measuring well flow rate - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to oil production, in particular, to measurement of well flow rate during its operation. Method involves measurement of difference in volumes of well liquid into space between tubing and casing pipes, measured in process of lowering polished pump rod. Difference in volumes of liquid in space between tubing and casing pipes is determined by volume of borehole fluid-displaced gas, located in casing pipe. Volume of displaced gas is measured by displacement of fluid from reservoir into a measuring cylinder, wherein maximum level of fluid in measuring cylinder is measured, said level being achieved when lowering polished pump rod from upper limit to lower limit positions.

EFFECT: technical result consists in simplifying and improving accuracy of determining flow rate.

1 cl, 1 dwg

Description

The invention relates to oil production, namely to measuring the flow rate of a well during its operation.

A known method of measuring the flow rate of productive intervals of wells, including sequential isolation of the intervals of perforation and determination of fluid flow from all uninsulated intervals, after which determine the integral and differential flow profiles [ed. testimonial. SU No. 983260, class ЕВВ 47/00].

The disadvantage of this method is its insufficiently high measurement accuracy, due to both insufficiently reliable isolation of the intervals of the reservoir, and large measurement errors of the total amount of fluid flow from uninsulated intervals.

A known method of determining the flow rate of a well, adopted as a prototype, includes measuring static and dynamic fluid levels in the space between the tubing and casing, measuring the level of fluid rise in the period until the next cycle of lifting the sucker rod pump and determining the flow rate by the difference in fluid levels in casing during the ascent and descent of the pump [US Pat. RU No. 2229593, cl. ЕВВ 47/00].

The disadvantage of this method is the complexity of its implementation, associated with the need for descent into the annulus of the level meter, as well as the low measurement accuracy due to the frequency of measurements.

The task is to simplify the method of determining the flow rate while improving accuracy.

The problem is solved in that in the method of measuring the flow rate of a well, including measuring the difference in the volume of well fluid in the space between the tubing and the casing, measured during the descent of the pump, in contrast to the prototype, the difference in the volume of fluid in the space between the tubing and the casing pipes are determined by the volume of gas displaced by the borehole fluid located in the casing, and the volume of gas displaced is measured by displacing the liquid from the reservoir into the measuring cylinder, this fixes the maximum liquid level in the graduated cylinder, achieved during the descent of the pump from the upper limit to the lower limit position.

Figure 1 shows a diagram of the implementation of the proposed method.

In the casing 1 there is a tubing 2 with a flow line 3. Inside the pipe 2, a polished rod 4 of the downhole pumping unit reciprocates. By pipe 5, the space between the casing 1 and tubing 2 is connected to the reservoir 6, which in turn is connected to the measuring cylinder 7. Using the float 8 and inductive ruler 9, the liquid level in the measuring cylinder 7 is transmitted to the information processing unit 10, to which are also connected the sensors of the upper limit position 11 and the lower limit position 12, controlling the process of movement of the polished rod 4.

The method of measuring well production is as follows.

When the polished rod 4 moves up, the pump lifts the well fluid, which is discharged from the tubing 2 through the flow line 3. In this case, the level of the well fluid in the space between the casing 1 and tubing 2 decreases due to suction by the pump. When in the upper limit position, the pump stops the absorption of fluid, which begins to flow into the annulus from the reservoir. In this case, the liquid level rises in the annulus, which leads to the displacement of gas from the annulus to the nozzle 5 and the reservoir 6. Under the influence of the incoming gas, the liquid from the reservoir 6 is forced into the graduated cylinder 7 provided with a float 8. The liquid level in the graduated cylinder 7 is measured by the interaction of the float 8 and the inductive ruler 9. Data on the value of the liquid level in the graduated cylinder 7 enters the information processing unit 10, and the reference is determined by the signal of the sensor 11, and the end tscheta - by the signal sensor 12. The flow rate corresponds to the well fluid volume in the graduated cylinder 7, measured for one pump descent. When lifting the pump, the level of the borehole fluid decreases, as a result of which a vacuum is created in the internal volume of the casing. This leads to the fact that the gas from the tank 6 is sucked into the cavity of the casing 1, the liquid from the measuring cylinder 7 is returned to the tank 6 and the measuring unit is restored to its original state. Thus, the application of the proposed method allows continuous monitoring of the flow rate of the well and the accumulation of a database of changes in the flow rate over a long period of operation of the well.

Compared with similar methods for measuring the flow rate of wells, the proposed technical solution has the following advantages:

- a simpler measurement technique that allows measurements in real time;

- a simpler design of the device implementing the proposed method;

- increased accuracy and reliability of measurements, due to the direct dependence of the volume of displaced gas from the flow rate of the well.

Claims (1)

A method for measuring well production, including measuring the difference in the volume of well fluid in the space between the tubing and the casing, measured during the descent and lifting of the polished pump rod, characterized in that the difference in the volume of fluid between the tubing and the casing is determined by volume displaced by the borehole fluid gas located in the casing, and the volume of displaced gas is measured by displacing the fluid from the reservoir into the measuring cylinder, while fixing t is the maximum liquid level in the measuring cylinder, achieved during the descent of the polished pump rod from the upper limit to the lower limit position.

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