EA030391B1

EA030391B1 - Method for determining an oil reservoir hydroconductivity, and device for implementing the same

Info

Publication number: EA030391B1
Application number: EA201650082A
Authority: EA
Inventors: Тельман Аббас Оглы Алиев; Аббас Гейдар оглы Рзаев; Сакит Рауф оглы Расулов; Гудрат Исфендияр оглы Келбалиев
Original assignee: Институт Систем Управления Национальной Академии Наук Азербайджанской Республики
Priority date: 2016-07-15
Filing date: 2016-07-15
Publication date: 2018-07-31
Also published as: EA201650082A1

Abstract

The invention is related to oil industry, in particular, to hydrodynamic well surveying, and can be used to determine reservoir bed parameters. The essence of the method according to the invention consists in determining the bed permeability coefficient Kdepending on bottomhole pressure during the well operation, reservoir thickness and oil viscosity. Test sampling of oil fluid is performed, the sample is separated from accompanying water and gas, and intensities of incident infrared radiation and of infrared radiation that has passed through the separated oil layer are measured. Optical density of oil is calculated, exponential dependence of the permeability factor at the initial time moment Kon optical density D is determined, absolute permeability Kand dynamical viscosity μof oil are determined, characterizing optical density Dis found, and hydroconductivity of the reservoir is calculated by the respective formula. The essence of the invention consists also in a device for implementing the invented method. The technical effect of the claimed invention is that it allows measurement of an oil reservoir hydroconductivity without interrupting the well operation. Results of calculations performed show that the method according to the invention reflects really filtration processes in an oil reservoir.

Description

The invention relates to the oil industry, in particular to the hydrodynamic methods of well research, and can be used in determining the parameters of the reservoir. The essence of the proposed method consists in determining the value of the coefficient of permeability of the reservoir Kf depending on the bottomhole pressure during well operation, the thickness of the reservoir and the viscosity of the oil. Carry out a trial selection of petroleum liquid, subjected to its separation from the associated water and gas and measure the intensity of the incident infrared radiation passing through the layer of separated oil. Calculating the optical density of the oil, determined by the exponential dependence of the permeability at the initial time of ₀ K absorbance Ό, absolute permeability Kf is determined, and a dynamic viscosity p _H oil are characterizing absorbance Ό _χ and calculated by the formula transmissibility formation. The invention consists also in the device that implements the inventive method. The technical effect of the claimed invention is that it allows you to measure the hydraulic conductivity of the oil reservoir without stopping the operation of the well. The results of the obtained calculations show that the proposed method actually reflects the filtration processes in the oil reservoir.

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The invention relates to the oil industry, in particular to the hydrodynamic methods of well research, and can be used in determining the parameters of the reservoir.

There is a method of determining the hydroconductivity of an oil reservoir (1), which consists in using a non-linear filtration law during non-stationary redistribution of pressure in the reservoir and changes in the elastic reservoir and fluid reserves associated with starting or stopping the well, changing its operation modes. In this case, during unsteady filtration in the reservoir, the hydraulic conductivity coefficient changes with a change in the pressure gradient on the borehole wall and the reservoir depression. In this method, the problem of determining the hydraulic conductivity of the reservoir (HP) according to the recovery curve of bottomhole pressure to reservoir pressure (HPC) is solved while the fluid flow continues after it stops. The conditional size of perturbations of the reservoir area from a well stop is determined depending on the logarithm of the function of the influence of fluid inflow into the well on the propagation in the reservoir of the perturbation front, which has a polynomial form of the 6th degree. The disadvantage of this method is that it does not show how GP is determined by ARC.

There is a method for determining the reservoir hydraulic conductivity (2), which includes stopping the well at the lower position of the pumping unit plunger, tracking the bottomhole pressure recovery rate at regular intervals during unsteady filtering mode after the well shutdown, building the bottomhole pressure recovery curve to the reservoir in semi-logarithmic coordinates, which is described The following formula:

where P _to - pressure in the circuit of the reservoir;

with the subsequent calculation of hydroconductivity according to the known formula (1).

The method allows to determine the HP with high accuracy, but the main disadvantage of this method is that to determine the HP well stops for a certain period (10-15 days), which from an economic and technical point of view is impractical.

The closest is the well-known method (3) of determining the HP, which measures the change in bottomhole pressure after a well is stopped or started, determines the value of the reservoir permeability coefficient Kf depending on the bottomhole pressure during well operation, measures the thickness of the reservoir (I) and oil viscosity (μ _Η ), build the curve of recovery of bottomhole pressure (HPC) in semi-logarithmic coordinates and calculate the value of the hydraulic conductivity of the oil reservoir by the known formula

₌ JF

The disadvantage of this method is that in most cases, especially for marginal wells, due to the limited capacity of the mathematical apparatus used in the method for determining the hydrodynamic (filtration) characteristics of the reservoir by the ARC, this method leads to significant errors in determining the HP. And besides, the use of this method is also possible only when the well is stopped.

The objective of the invention is to develop a method for determining the SE in normal operation of the well and the creation of a device that implements the inventive method.

The essence of the proposed method of determining the hydraulic conductivity of the reservoir is that determine the value of the coefficient of permeability of the reservoir Kf depending on the bottomhole pressure during operation of the well, measure the thickness of the reservoir and the viscosity of the oil. Carry out a trial selection of petroleum liquid, subjected to its separation from the associated water and gas and measure the intensity of the incident infrared radiation passing through the layer of separated oil. Calculate the optical density of oil, determine the exponential dependence of the permeability coefficient on optical density I), determine the absolute permeability Kf and the dynamic viscosity μ _{Η of} oil, find the characteristic optical density 1) _x and calculate the value of the hydraulic conductivity of the oil reservoir by the formula

where ξ is the hydraulic conductivity of the formation, cP;

And - power (thickness) of the reservoir, m;

a, b, c are the conformity coefficients, which are determined experimentally;

K ₀ - the value of the permeability coefficient in the initial period of operation, determined by

core;

1) _x - characterizing the optical density, determined by the method of tangents to the curve of the exponential dependence (Kf) on I);

Dy P - pressure gradient, determined taking into account the depression of the reservoir and the distance from the supply circuit to the wellhead.

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In contrast to the known methods of determining the hydraulic conductivity of the reservoir, based on the study of wells with unsteady conditions along the pressure recovery curve, the claimed method uses a completely new method of hydrodynamic studies of the oil reservoir, according to which the permeability of the oil reservoir is determined by the effect of infrared radiation on oil and the dependence of the permeability coefficient is detected and oil viscosity from oil optical density.

The method is as follows.

Carry out a trial selection of petroleum liquid in the tank and subjected to its separation from the associated water and gas. The intensity of the incident infrared radiation 1 ₀ and radiation I transmitted through the vessel with oil is measured, the optical density (Ό) of the light-absorbing medium (oil) is calculated, and using the well-known formula Ό = 1β (Ι ₀ /), an exponential dependence curve is constructed (Fig. 1) the permeability coefficient at the initial time K ₀ from the optical density, according to which the tangential method is used to characterize the optical density Ό _χ , determine the absolute permeability Kf and the dynamic viscosity μ _{Η of} oil using the formulas

K _f = K „exp (- £) _;

Dn = apr (b);

And according to the well-known formula for determining the hydraulic conductivity of the formation

LKF

Day

taking into account the obtained values of the absolute permeability Kf and dynamic viscosity μ ,, oil, calculate the hydraulic conductivity of the reservoir by the formula

, _ ^s ' ^{L / s} ° ^exp I ^{zgL p}

ξ ~ PH ^_ aexp (b)

where ξ is the hydraulic conductivity of the formation, m ³ / Pa-s;

And - power (thickness) of the reservoir, m;

a, b, c is the coefficient of conformity, which is determined experimentally;

K0 - the value of permeability coefficient in the initial period of operation, determined by core, m ² ;

Ό _χ - characterizing the optical density, determined by the method of tangent to the curve of the exponential dependence (Кф) on;

9 ^gas ^ · ^p - pressure gradient, determined taking into account the depression of the reservoir and the distance from the supply circuit to the wellhead, Pa / m.

The introduction of 9 ^{hectares (} ^ ^p into the proposed algorithm for determining the hydraulic conductivity of the reservoir is explained by the fact that it directly affects the value of K. With increasing value of dB P, the curve of the exponential dependence K - Ό, without changing its form, shifts up, and with decreasing dB P) way down

dgy P =

ΔΡ

where ΔΡ is formation depression;

1 - distance of the well supply circuit to the bottom, m.

Example: a = 11.09; B = 1.4208; E = 1; K ₀ = 1 -10 ^-12 μm ² ; Ό _χ = 0.5; And = 10 m; 9 ™ ^ρ = 1,2; c = 5.18.

wherein Ό * = 10 ^-12 m ² - Darcy; SP - centipoise, Pas - Pascal - second.

Due to the fact that the inventive method is based on a completely new approach to the hydrodynamic study of an oil reservoir, which uses the revealed dependence of the permeability coefficient and viscosity of oil on optical density under the influence of infrared radiation on oil, the invention also consists in the device that implements the inventive method and unparalleled. The device contains a sampler located on the flow line of the well, and a separator sequentially connected with it for separating oil from associated water and gas and a tank for separated oil. On both sides of the tank with oil are the source and receiver of infrared radiation associated with the transducer signals of infrared radiation, the outputs of which are connected to the control unit and display.

Therefore, the inventive method and device meets the criteria of "novelty" and "technical level".

A schematic block diagram of the inventive device is presented in FIG. 2

The device contains: 1 - sampler; 2 - separator; 3 and 4 - respectively the source and the reception - 2 030391

infrared nickname; 5 - capacity for oil; 6 and 6'- converters; 7 - control and display unit. The device uses standard and well-known devices, such as:

source of infrared radiation - TZL6100; infrared receiver - T30R1738; signal amplification unit - 7787;

microprocessor -LTMEOL or R1C 16R877; indicator - AL304;

cable - flat ribbon cable РКС 1-09-31; bracelet - plastic.

The frequency of the TZL6100 source is up to 300 kHz.

The frequency of the receiver T30R1738 - 38 kHz (carrier frequency).

The device works as follows.

Oil fluid (oil - water) with gas from the discharge line 8 of the production well 9 through the sampler 1 enters the separator 2, where water and gas are separated and removed along lines 10 and 11, and the separated oil from the separator is fed into the container 5 to measure its optical density. Infrared radiation from an IR source (3) passes through a tank of oil. Part of the radiation is absorbed by the oil, and the transmitted radiation is captured by the IR receiver (4). The output of IR (4) receive signals associated with changes in the intensity of the absorbed radiation. The measured values and I through the transducers 6 and 6 'enter the control and display unit 7. In the control unit, the hydroconductivity of the reservoir is determined by the measured and calculated parameters and displayed on the indicator.

The technical effect of the claimed invention is that it allows you to measure the hydraulic conductivity of the oil reservoir without stopping the operation of the well. The results of the obtained calculations show that the proposed method actually reflects the filtration processes in the oil reservoir.

Literature

1. RF patent №2301886, 08.17.2006, "Method for determining the hydraulic conductivity of the formation".

2. Eurasian application No. 201400794, 10.2015, "Method for determining the hydraulic conductivity of the formation."

3. Robert Erlager "Hydrodynamic methods for well testing". Moscow-Izhevsk, 2006, 512 p. (prototype).

Claims

CLAIM

1. The method of determining the hydraulic conductivity of an oil reservoir, at which the value of the coefficient of permeability of the reservoir Cf is determined depending on the bottomhole pressure during well operation, measures the thickness of the reservoir and the viscosity of the oil, characterized in that they carry out a test selection of the oil liquid, subject it to separation from associated water gas and the measured intensity of the incident ₀ 1 I and transmitted through the layer of separated oil infrared radiation, is calculated optical density of oil build-dependent exponential curve of coefficient of permeability of the optical density Ό, absolute permeability Kf is determined, and a dynamic viscosity p _H oil are characterizing absorbance Ό _χ and calculated by the formula transmissibility reservoir

where ξ is the reservoir hydraulic conductivity, m ³ / Pa-s; d - thickness (thickness) of the reservoir, m;

a, b, c is the coefficient of conformity, which is determined experimentally;

K ₀ - the value of permeability in the initial period of operation, determined by core, m ² ;

Ό _χ - characterizing the optical density, determined by the method of a tangent to the curve of the exponential dependence (Кф) on;

9 ^{Γαά p} - pressure gradient, determined taking into account the depression of the reservoir and the distance from the supply circuit to the wellhead, Pa / m.

2. A device for implementing the method according to claim 1 contains a sampler located on the flow line of the well, a separator sequentially associated with it for separating oil from associated water and gas and a container for separated oil, on both sides of which the source and receiver of infrared radiation are located with infrared signal converters, the outputs of which are connected to the control and display unit.

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