Method for determination of product water cut in oil producing well

FIELD: oil and gas industry.

SUBSTANCE: determination is carried out in a well equipped with a tubing string with an electric-centrifugal pump and a return valve at the end. In order to determine water cut the well is selected in the middle of an oil deposit with production modes close to the average values for the deposit. The well is operated not less than the time required to reach full operation. The well is stopped and process holding is made till gas separation from the well product and breakage into oil and water. Height of the liquid column is measured, volume of the water cut is determined against the boundary line of liquid and gas and water and oil.

EFFECT: improving accuracy of the water cut determination in the well.

 

The invention relates to the oil industry and can find application in the determination of water production oil wells

There is a method to determine the water content of the liquid products of oil wells, which consists in the fact that the representative fluid sample contained in a vertical cylindrical vessel, bring the sludge, treatment with chemicals and heat to the state of at least partial separation into oil and water. Measure the height of a column of liquid, the hydrostatic pressure, and then in the process of emptying of the vessel produces a continuous measurement of the hydrostatic pressure and the height of the liquid column. The density of water and oil in the composition of the liquid determined by dividing the difference between the maximum and the current differential hydrostatic pressure corresponding to the difference of height of the liquid column at the beginning and the end of discharge. Accumulate the data array. Build a graph of the density dependence of the drained liquid from the height of the liquid column or time of emptying. Choose within the upper and lower horizontal linear plots of the density, respectively, water and oil. For selected values of the densities of water and oil determine the mass cut production wells. The technical result is a simplification of the algorithm for determining the square is tastey water and oil in the composition of production wells, improving the accuracy of measuring high and low water production wells (RF patent No. 2396427, publ. 10.08.2010)

The closest to the proposed invention the technical essence is a method of measuring the rate of production of oil wells in sealed systems of collection, in which the measuring tank (S) calibrated volume after purging the well production (COP) fill partially separated PS during a pre-assigned with the maximum performance time at the open on the gas collector and closed drain liquid lines. Upon expiration of the appointed time of the arrival of the cops in THEIR stop. Partially separated PS contained in the tank level gauge S, treated with chemicals, heated and maintained to a state of separation into oil and water. Then measure the height of a column of liquid, the hydrostatic pressure (GSD) and temperature. Calculate the performance of the fluid. Then the relative positions of the dividing lines and the liquid - gas and water - oil judge volume is watering. The mass ratio of water - oil determined by applying values of water density, measured in tank sensor S, and the density of the oil. Thus take into account the amount of fluid that remains in the separator system And the after "purging" PS before beginning the procedure of measurement. Then simultaneously with the closing of the gas and the opening of the liquid lines to the collector resume receipt TS in S; determine the emptying rate S and the excess pressure, the calculation of productivity. The density of the water to determine the full withdrawal of water from the tank level gauge during emptying after resume receipt TS in S by dividing the difference between the SRS column of liquid in the tank level gauge before and after care part of the water column on the difference between the respective levels of the liquid column. And the density of oil is determined after the full withdrawal of water from the tank level gauge during emptying after resume receipt TS in S by dividing the value of HSD, remaining at the time of measurement of the liquid column at its height (patent RF №2299322, publ. 20.05.2007 - prototype).

A common disadvantage of the known technical solutions is the low accuracy of determination of the water content resulting from the movement of production wells in the measuring container.

In the proposed invention solves the problem of improving the accuracy of determination of water production wells.

The task is solved in that in the method for determining the water cut of the oil wells, including separation from the production wells gas, conducting the exposure to the state of separation into oil and water, from which irenie height of the liquid column, the relative positions of the dividing lines and the liquid - gas and water - oil determination of the volume values watering, according to the invention the determination is carried out in the wells, which supply the column tubing with electrical submersible pump and a check valve on the end, to determine the water content choose a well located near the middle of the oil fields, modes of production, close to the average reservoir, the well exploited least the time of the ramp, and before separation from the production well gas and exposure to state of separation into oil and water to stop the well and conduct technology exposure.

The invention

The accuracy of determination of water production (oil) wells is one of the most important tasks in the development control object, determining the profitability of wells, evaluation of the effectiveness of technologies to improve oil recovery.

Upon reaching values of water content in the 98-99% often decide to stop wells (translated in an inactive or not operational Fund) or the transition to the overlying horizons. However, the existing technology to determine the water content is sampling at the mouth of the wells in a volume of the first hundred milliliters, do not give full HC the arrangement in its accuracy. Errors of 2-3% in prolific, highly watered the Fund may change the assessment of the profitability of the well operation.

To improve the reliability of determination of water content of produced fluids determination is carried out in the wells, where the deep well pumping equipment use electrical submersible pump lowered in the tubing pipe, equipped with a check valve. The technology involves determining the water content directly into the well without removing deep-pumping equipment and to lift the fluid to the surface.

The determination is carried out in the wells, which supply the column tubing with electrical submersible pump and a check valve on the end. To determine the water content choose a well located near the middle of the oil fields, modes of production, close to the average reservoir (differing by no more than 15%). Well not operate less time out on the operating mode. The well is stopped by closing the valve cut from the pipeline, while the check valve prevents flow of fluid from the column tubing in the well. The result is severed vessel - the internal cavity of the column tubing equal to the volume of 2-3 m3that several thousand R is C exceeds the amount of the standard sample. This cut off the vessel has significantly stretched almost in the vertical direction form, which increases the efficiency of gravity separation of gas-liquid mixture.

After stopping the well was incubated for the time required for gravity separation of the phases (gas-oil-water). In this period the selected gas release through the lubricator valve. The time is determined empirically with respect to temperature of the produced products, the water content in the initial stage of this work clarifies the sampling in the oil cap with the use of deep samplers. To improve the phase separation process through the lubricator valve, you can add oil soluble demulsifier. Further, through the lubricator valve descending into the column tubing resistivity meter, moisture meter or other similar device, record the level of the liquid and oil-water partition. Calculate the height of the oil cap and its relation to the total height of the liquid column in the tubing pipes determine the volume fraction of oil and, accordingly, calculate the production watercut:

W volume = 1-h oil/h of liquid (%)

The use of a manometer in conjunction with the hygrometer also allows to calculate the density of oil "caps" and, respectively, p is tverdal complete phase separation.

Specific example

Well No. 1387 Aktashskoe square Novo-elkhovskoye field is located in the middle of the oil fields, modes of production, close to the average for deposits: the rate of 80 m3/day, bottom-hole pressure of 11.7 MPa. Well exploit the 30 days, i.e. at least the time of the ramp. The well produces oil with kievskogo and pashian horizons using the following deep-pumping equipment - centrifugal pump ACNM-60-1200 lowered to a depth of 1400 m on the column tubing with a diameter of 73 mm Above the centrifugal pump check valve. Before stopping the well through the sampler selects a control sample, which showed a water content of 100%. Well stop, conduct technology exposure during the day and produced a study on the water content. We obtained the following results: the level of the liquid - 264,5 m, oil-water section - 288 m i.e. oil "cap" is 23.5 m when the liquid column in the tubing pipe 1135,5 m (1400-264,5 m). Thus, the cut makes 97.9%. The separation efficiency was confirmed as the samples deep sampler with two points in the oil "cap" (the water content of 0.75% and 0.3%), and the pressure gauge (pressure at the oil-water section was 0.2 MPa, th is corresponds to the density of 23.5 m oil cap 0,85 g/cm 3i.e. oil).

Thus, the proposed method allows to determine the water content more accurately than known.

The application of the proposed method will allow to solve the problem of improving the accuracy of determination of water production wells.

The method for determining the water cut of the oil wells, including separation from the production wells gas, conducting the exposure to the state of separation into oil and water, the measurement of the height of the liquid column, the relative positions of the dividing lines and the liquid - gas and water - oil determination of the volume values of water content, wherein the determination is carried out in the wells, which supply the column tubing with electrical submersible pump and a check valve on the end, to determine the water content choose a well located near the middle of the oil fields, modes of production, close to the average reservoir, well not operate in less time output in work mode, and before separation from the production well gas and exposure to state of separation into oil and water to stop the well and conduct technology exposure.



 

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