The method of regulating the flow of water into an oil well of multilayer deposits
The invention relates to the field of the oil industry and can be used for watering operation of oil wells with multi-layer heterogeneous structure of the productive interval. The technical result of the invention is the provision of an optimum mode of operation of wells due to selective throttling of the flow of products from each formation, carried out on differentiated criteria for their watering. For this purpose, the method includes the control of water production wells and the change in the value of liquid extraction depending on the values of its water content. The control of water production wells is carried out by simultaneously measuring the current values of water production from each of the productive formation. In the process control record layers with a water content that does not comply with the maximum allowable values for each layer is determined from the condition of minimizing the unit cost of produced from each of the above-mentioned formation of irrigated production. The magnitude of the selection of these layers change throttling flow to exclude the error current value is m measuring its electrical conductivity AC. 1 C.p. f-crystals, 1 Il.
The invention relates to the field of the oil industry and can be used for manual watering oil wells multilayer deposits.
The known method of operation of the wells of a multi-reservoir oil fields, including simultaneous selection of products from oil and water reservoirs and the production of oil-water reservoir to an acceptable oil water cut or reduce its flow rate and then disable the specified layer (see patent RU NO. 2100580, E 21 IN 43/14, 1996).
This method solves the problem of regulating the flow of water into the well from the oil and one oil-water reservoir by isolating the latter, i.e. in discrete mode, in compliance with the conditions of equal pressure in each reservoir, and may not be used for the case of the n-th number of heterogeneous reservoirs with different cuts and ensuring cost-effective operation of wells.
Known methods closest to the proposed to the technical essence and the achieved result is a method for controlling irrigation wells, based on the measurement of the optical characteristics of oil-water the water the water content in oil-water flow, the definition they misalignment of the sign and magnitude of flooding oil and changing it for throttling flow to reduce the error of these parameters to valid values (see Michaell, Chichester, Iohon Witey and soon. Petroleum Well Construction, 1997, p. 612).
The main disadvantages of this method include:
assessment is actually integral characteristic values of water production and regulate it accordingly throttling flow of goods directly at the wellhead, which does not allow to take into account hydrodynamic and geological properties of the individual layers;
- define valid values for the water content of crude oil on the basis of traditional criteria based on the use of information about critical values of water production and optimizing the actual cost of oil dehydration and do not take into account the mutual influence of aquifer parameters in the process of their generation.
Noted deficiencies cause the methodological error of the method, and the use of the optical characteristics to estimate the water content leads to more instrumental errors and the limitations of this method. The latter, in particular, is associated with the need is generated simultaneously productive areas, and with the influence of the fluid composition on the optical characteristics of the transmitter and receiver, which are random in nature.
The present of the invention is to provide a method of regulating the flow of water into an oil well of multilayer deposits, ensuring optimal operation mode watering oil wells due to selective throttling of the flow of products from each formation, carried out on differentiated criteria for their watering.
This object is achieved in that in the method of regulating the flow of water into an oil well from a stacked field in the course of its operation, including control of water production wells and the change in the value of liquid extraction depending on the values of its water content, according to the invention the control of water production wells is carried out by simultaneously measuring the current values of water production from each of the reservoir, in the process control record layers with a water content that does not comply with the maximum allowable values for each layer is determined from the condition of minimization Tbore of these layers throttling flow to exclude the error of the current values of the water content with valid values.
It is advisable to control the water content of the product be done by measuring its electrical conductivity AC.
The method consists in the following.
When regulating the flow of water into the well is proposed as a criterion for the limit values of the water content of oil to use unit cost of oil production
With regard to the conditions of multilayer deposits regulation of water inflow into the borehole, it is advisable to carry out not on the basis of information on allowable values of water content for the entire production wells (wickede), and differentiation for each layer.
This recommendation below illustrates the dependence of the specific costs (Z %) the degree of water taken from the well fluid (q, %).
The drawing shows the analytical dependence characterizing the cost per unit of extracted oil (unit costs) from wells from its water content (curve 1) and separated by layers (curves 2). The family of curves 2 differ in the value of oil production rate (Q1>Q2>Q3>Q4). Thus, the higher the flow rate, the lower the unit costs. The area under the curve 1 is essentially the area of the minimum costs for operation of the well watered the each layer.
The proposed method of regulating the flow of water into an oil well of multilayer deposits implemented as follows.
In a well operating multilayer deposits, down the column tubing with pump, packers, measuring the water content in the form of conductivity sensors, actuators throttle type in the number equal to the number of layers, and lines for transmission to the surface information on the amount of water production and to power the actuators.
At the wellhead place the source of electrical power, the controller and switching equipment.
Force, by means of actuators (full throttle), overlapping group of formations, open sequentially, alternately one layer and determine the flow rate and the water content of each layer.
For each of the layers determine the maximum water content at which, proceeding from the condition of minimization of unit costs, appropriate to their operation.
Using the controller for each of the layers set videopreteen the value of the water content of oil, compare it with the current value for each layer perform re is e, for example, can be made in the form of adjustable valves.
The following is an example implementation of the method using as the parameter that determines the degree of water contamination of the oil conductivity.
The use of conductivity is due to the fact that oil has a low electrical conductivity, and formation water based, due to the presence of dissolved salts, is a good conductor of electric current.
Pre-make sampling of oil and water layers and carry out laboratory studies of electrical conductivity of the mixture by any of the existing techniques for different ratios of water and oil.
According to the data obtained experimental build (reference) dependence of the conductivity (relative resistivity) to the amount of water in the oil, which is approximated by the equation
where,0- the resistivity of formation water and oil, respectively [Om];
q is the relative amount of water in the liquid;
And the empirical coefficients.
During operation of the wells through conductivity sensors constantly flows of electricas the dependence of the current between the electrodes from the water content of the oil may be represented as
where- constant electrode of the sensor cell conductivity;
U is the potential difference at the electrodes of the conductivity sensor [On];
S and l is the surface area of the electrodes and the distance [mm2];
- specific resistance of the liquid flowing through the electrode sensors conductivity [W];
q - value of the water content of the oil;
And the empirical coefficients.
Because each of the layers have been previously determined values of the empirical constants and coefficients of equation (2), the controller sets the current value between the electrodes and the corresponding threshold (valid) oil water cut for each of the layers individually.
Thus, during operation compares the current value of the current flowing through the liquid in each of the productive layers with the specified value on reference dependence. They misalignment determine the amount of oil watering and implement throttling flow to eliminate this error.
In the proposed method by ranking the reservoir water saturation and pump down on the Tami and valid values watering.
1. The method of regulating the flow of water into an oil well from a stacked field in the course of its operation, including control of water production wells and the change in the value of liquid extraction depending on the values of its water content, characterized in that the control of water production wells is carried out by simultaneously measuring the current values of water production from each of the reservoir, process control, recording layers with a water content that does not comply with the maximum allowable values for each layer is determined from the condition of minimizing the unit cost of produced from each of the above-mentioned reservoir flooded products and change the value of the selection of these layers throttling flow to avoid misalignment of the current values of the water content with a valid value.
2. The method according to p. 1, characterized in that the control of water production is carried out by measuring its electrical conductivity AC.
FIELD: oil and gas extractive industry.
SUBSTANCE: device has operation columns of upper and lower well zones, placed eccentrically one inside the other in upper zone of well, double airlift column, mounted in upper well zone, and double airlift column, connected to operation well of lower well zone, separation column, mounted coaxially to operation column of upper well zone, and cementation pipe. According to invention, in a well with significant power of non-productive zone it is equipped with additional separating column with cleaning channels for lowering drilling tool therein and drilling well to lower well zone with removal of drilling slurry by double airlift column of upper zone through cleaning channels. Additional separating column is combined coaxially with operation column of lower well zone and is rigidly fixed to separation column.
EFFECT: higher efficiency.
1 dwg, 3 cl