RU2346150C1 - Oil deposit development method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil industry, and can be used when developing an oil deposit. In this case there is a working agent injected through pressure wells, oil is withdrawn through production wells, and impact on the deposit in compliance with solar and lunar floods and ebbs. Periods of solar and lunar floods and ebbs are defined according to low frequency tide waves. During solar and lunar floods there intensified is oil production in production wells; during solar and lunar ebbs there intensified is injection of working agent through pressure wells. Formation pressure is maintained not less then hydrostatic one. During solar and lunar ebbs there carried out is repair work, repair-and-insulating work, and work on well injection.

EFFECT: improving oil deposit production rate.

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Description

The invention relates to the oil industry and may find application in the development of oil deposits.

A known method of increasing oil production, according to which excite elastic vibrations in the reservoir by means of vibration. Pre-measured in the reservoir energy of acoustic noise in different phases of the earth's tides. Set the phase of the Earth's tides, corresponding to the maximum energy of acoustic noise. The impact on the formation is carried out in the established phase of the tides until the maximum increment of the total energy of acoustic noise and stabilization of the filtration properties of the formation from the beginning of the impact (RF Patent No. 2046936, published. 1995.10.27).

The known method does not take into account that during vibration exposure there is an increase in compression of the earth's crust (compression of cracks), and after vibration exposure there is an expansion of the earth's crust, and expansion and compression of cracks from vibration are not synchronized with similar stretchings and compressions from lunar-solar tides, as a result of which the effect of vibration is either reduced or completely disappears depending on the degree of phase mismatch.

Closest to the technical nature of the present invention is a method of increasing oil recovery and oil production, according to which external physical effects of vibration or fluid injection are produced in the formation bed periodically depending on tidal movements in the earth's crust, and they are carried out during compression of the earth's crust ( RF patent №2217581, published. 2003.11.27 - prototype).

The disadvantage of this method is that the tensile energy of the earth's crust is not used, and the compression energy is used without taking into account the presence of low-frequency and high-frequency tidal waves. All this reduces the oil recovery of the reservoir.

The proposed invention solves the problem of increasing oil recovery deposits.

The problem is solved in that in the method of developing an oil deposit, including pumping a working agent through injection wells, taking oil through production wells and influencing the reservoir in accordance with solar-lunar tides, according to the invention, the periods of solar-lunar tides are set at low frequency tidal waves, during the period of solar-lunar tides intensify oil production in producing wells, during the period of solar-lunar ebbs intensify the injection of the working agent through the discharge nye wells, the formation pressure is not maintained below hydrostatic, wherein during the solar-lunar tides performed repair work, repair and insulation work, work completions.

SUMMARY OF THE INVENTION

Known methods of developing oil fields, taking into account the influence of solar-lunar tides on the state of the oil deposit, are ineffective due to the far from full use of the additional formation energy that arises from this. As a result, the oil recovery of the reservoir remains at a low level. The proposed invention solves the problem of increasing oil recovery deposits. The problem is solved as follows.

When developing an oil deposit, the working agent is injected through injection wells, oil is extracted through production wells and the effect on the reservoir is in accordance with solar-lunar tides. The periods of the solar-lunar tides are established by low-frequency tidal waves. During the tidal period intensify oil production in producing wells, during the tidal period intensify the injection of the working agent through injection wells. In this case, the reservoir pressure is maintained no lower than hydrostatic. During the period of the solar-lunar ebb, repair work is carried out, repair and insulation work, well completion work.

Solar-lunar tides occur for the following reasons.

Under the influence of the mutual attraction of particles, the body tends to take the shape of a ball. If these bodies rotate, then they are deformed, compressed along the axis of rotation. In addition, a change in their shape also occurs under the influence of mutual attraction, which causes phenomena called tides. Long known on Earth, they received an explanation only on the basis of the law of gravity.

Consider the acceleration created by the attraction of the moon at various points on the globe (figure 1). Since points A, B, and O are at different distances from the moon, the accelerations created by its attraction will be different.

The difference in the accelerations caused by the attraction of another body at a given point and in the center of the planet is called tidal acceleration. Tidal accelerations at points A and B are directed from the center of the Earth. As a result, the Earth, and first of all its water shell, stretches in both directions along the line connecting the centers of the Earth and the Moon. At points A and B, an ebb is observed, and along the circle, the plane of which is perpendicular to this line, the ebb tides on Earth. The gravitation of the Sun also causes hot flashes. Tides are observed not only in the hydrosphere, but also in the atmosphere and in the lithosphere of the Earth and other planets.

The moon moves under the influence of gravity, mainly of two celestial bodies - the Earth and the Sun, while solar gravity is greater than Earth. The moon is at an average distance of 384,400 km. At the peak, this distance increases to 405,500 km, and at the perigee it decreases to 363,300 km. The Moon completes a complete revolution around the Earth in 29.5 days, if the Sun is taken as the reference point. During this period, called the synodic month, it goes through all phases from the new moon to the first quarter, the full moon, the last quarter and again returns to the new moon phase. The period of revolution of the moon around the earth, when it occupies a consistently identical position among the stars when observed from the earth, is called the sidereal month. It is 27.3 days.

Figure 2 presents a graph showing the distance from the moon to the earth for 2007. From the graph it can be seen that the distance varies both during the day, so there are monthly changes.

In accordance with the movement of the Moon and the Sun, tides occur in the area of the oil field. To implement the proposed method in the field of research. The characteristics of the tidal waves are determined. For this purpose, instruments recording pressure over time are installed in the wells at the marks of the productive horizon. Their location is chosen in such a way as to cover the entire area of the field with uniform observations and with the exception of the influence of technogenic factors on a productive development object.

Figure 3 shows the recorded dynamics of reservoir pressure in these conditions. From figure 3 it follows that in the field there are daily, weekly, monthly and annual changes in reservoir pressure, correlated with the position of the moon. The daily periods of the solar-lunar tides are attributed to high-frequency, the monthly to low-frequency, with a longer period - infra-frequency. During the period of low-frequency tidal waves of solar-lunar tides, oil production in production wells is intensified in proportion to the amplitude values, i.e. increase well production. Water injection during this period is carried out in the same volumes or limited. During the period of solar-lunar ebbs, the injection pressure and flow rate increase, i.e. intensify the injection of the working agent through injection wells. In this case, the reservoir pressure is maintained no lower than hydrostatic. Since during the low tide the reservoir pressure decreases and, consequently, the resistance of the formation to the impact, during this period of solar-lunar low tides, repair work is carried out, associated with the necessity of killing the wells, repair and insulation work to isolate the absorption zones or zones of water inflows, as well as completion work wells associated with perforation and well development.

When compressing oil-filled cracks and pumping fluid into injection wells, oil is displaced through cracks and other channels to production wells.

Liquid injection into injection wells enhances oil displacement from fractures and accelerates their delivery to production wells, and the gradual replacement by oil of oil in the pore space prevents residual deformation and subsidence of the earth's crust on the earth's surface, which is important for buildings and structures.

The proposed method is suitable for oil, as well as for gas fields of any structure of the field and reservoir, as well as rock composition.

Concrete example

An oil reservoir with the following characteristics is being developed: depth 1200 m, initial reservoir pressure 12 MPa, reservoir temperature 24 ° C, reservoir thickness 15 m, average porosity 19.0%, permeability 0.7 μm ² , oil saturation 0.74 unit ., oil viscosity 40 MPa · s, oil density 0.84 g / cm ³ . The deposit is developed by 2 injection wells and 10 production wells. The characteristics of the tidal waves are determined. To do this, in observation wells at the level of the productive horizon, instruments are installed that record the pressure in time. The resulting dependence is presented in figure 3. In accordance with the change in reservoir pressure with its increase, the production rates of production wells are increased by lowering the bottomhole pressure by the amount of increase in reservoir pressure and the injection pressure is reduced by the same amount of increase in reservoir pressure. With a decrease in reservoir pressure, they return to the initial production rates of production wells and increase the injection pressure of the working agent by the amount of decrease in reservoir pressure.

Repair wells conduct repair and insulation work during the period of lowering the reservoir pressure.

As a result, oil recovery increased by 0.8%, while the prototype oil recovery increases by only 0.2%.

The application of the proposed method will improve oil recovery deposits.

Claims (1)

A method of developing an oil deposit, including injecting a working agent through injection wells, extracting oil through producing wells and influencing the reservoir in accordance with solar-lunar tides, characterized in that the periods of solar-lunar tides are set on low-frequency tidal waves, during the tidal period intensify oil production in production wells, during the tidal period intensify the injection of the working agent through injection wells, reservoir phenomenon is not maintained below hydrostatic, wherein during the solar-lunar tides performed repair work, repair and insulation work, work completions.

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