RU2449115C2 - Method of gas-condensate accumulation development - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method includes accumulation drilling-out by wells, pumping of working substance into the accumulation - dry hydrocarbonic gas and formation fluid withdrawal. According to the invention oil well tubing working in the accumulation is equipped with variable magnetic field emitters and the wells are equipped with double completion with two opening intervals - upper and lower. Note that accumulation development is done in two stages. At the first stage variable magnetic field is created in the formation ensured by engagement of emitters on well tubing and formation fluids are withdrawn through both opening intervals of the wells with accumulation development in depletion drive. Note that dry hydrocarbonic gas is pumped to the upper opening intervals of the wells at the second stage of development after obtaining the pressure of maximum condensation. Formation fluid withdrawal that turned into liquid condensate is done from the lower opening intervals.

EFFECT: increase of condensate output and decrease of power consumption in the course of method implementation.

3 cl, 5 dwg

Description

The invention relates to the oil and gas industry, in particular to methods for developing gas condensate deposits.

A known method of developing a gas condensate reservoir, including its drilling by wells and the selection of reservoir fluids [1].

The disadvantage of this method is the significant loss of condensate that falls in the formation into the liquid phase when the pressure decreases during development in the mode of depletion of reservoir energy, and the method does not provide for measures to involve the condensate deposited in the formation into development.

There is a method of developing gas condensate deposits, including drilling wells with wells, pumping dry hydrocarbon gas into the reservoir and selecting formation fluids [2].

The disadvantage of this method is the low condensate recovery and significant costs for its implementation, since both the construction of compressor stations and the gas compression process itself require significant costs.

The aim of the invention is to increase the condensate recovery and reduce energy consumption for the implementation of the method, due to the impact on the reservoir by physical fields.

This goal is achieved by the fact that in the method of developing gas condensate deposits, including drilling the deposits with wells, pumping dry hydrocarbon gas into the reservoir and selecting formation fluids, the tubing of the producing wells are supplied with alternating magnetic field emitters, and the wells themselves are double-terminated with upper and lower opening intervals, while the development of the deposits is carried out in two stages, and at the first stage in the reservoir create an alternating magnetic field due to the drive of the emitter variable magnetic field installed on the tubing, and produce reservoir fluids through both opening intervals with the development of reservoirs in the mode of depletion of reservoir energy, and dry hydrocarbon gas is injected at the second development stage into the upper opening intervals after reaching the pressure in the reservoir maximum condensation with simultaneous selection of the condensate deposited in the liquid phase through the lower opening intervals, while in the process of displacing the condensed condensate with dry gas the pressure is maintained at the maximum condensation pressure level, and the maximum condensation pressure is determined by the condensation isotherms constructed from samples of reservoir fluids taken from a given reservoir.

The claimed technical solution is based on the well-known from the theory the thesis that the treatment of gas condensate systems with a magnetic field and especially with an alternating magnetic field can intensify the processes of gravitational separation of these systems into gas and liquid condensate [3].

The development of a reservoir in the mode of depletion of reservoir energy with a decrease in the reservoir pressure to a maximum condensation pressure in the first stage and the subsequent displacement of oil with dry gas at pressures equal to the maximum condensation pressure in the second stage prevents the evaporation of the condensate deposited in the formation and ensures an increase in the condensate yield of the formation. Based on these ideas, a method for the development of a hydrocarbon deposit is proposed, in which the increase in condensate recovery is provided due to the intensification of the yield and loss of condensate in the formation itself.

The technical solutions known on the topic (including the analogue and prototype) do not contain information about the possibility of increasing condensate recovery by treating the formation with a magnetic field and intensifying condensate deposition in a porous medium, on the contrary, the cycling process, which is implemented in the prototype, is aimed at preventing retrograde phenomena. In the claimed technical solution, in contrast to the prototype, it is proposed to intensify these retrograde phenomena in order to increase condensate recovery.

The literary source [3] contains information on increasing the condensate yield during the processing of gas condensate systems by alternating magnetic fields, but in no way on enhancing this process in reservoir conditions.

The above allows us to conclude that the claimed technical solution meets the criterion of "significant differences".

Figure 1 presents a diagram of the creation of a magnetic field in a gas condensate deposit, figure 2 shows the condensation isotherms from [3].

The method is implemented as follows. The gas condensate reservoir 1 is drilled with wells 2, into which tubing string 3 is lowered with alternating magnetic field emitters 4 at the bottom and packers 5. Well 2 is equipped with a double completion with an upper opening interval of 7 and a lower interval of 9.

The development of reservoir 1 is carried out in two stages. At the first stage of development, reservoir fluids are selected from the reservoir through both intervals of the opening of the well in the mode of depletion of reservoir energy. The reservoir pressure is reduced. The drainage of the reservoir is carried out until the pressure drops to the maximum condensation pressure (Fig.2-5). In this case, condensate 6 will fall into the liquid phase and accumulate 6. Simultaneously with the start-up of the wells, emitters 4 are initiated from the wellhead. In this case, an alternating magnetic field is formed in the reservoir, which intensifies the process of condensate accumulation 6.

With the achievement of the maximum condensation pressure, the selection of reservoir fluids with a decrease in reservoir pressure is stopped, since otherwise evaporation of the precipitated condensate will occur (Figs. 2-5).

Next, they go to the second stage, in which dry hydrocarbon gas is injected into the upper opening intervals of 7 wells, and condensate 6, which has previously precipitated in the reservoir, is pumped through the lower 9 intervals. The injected gas forms a gas cap 8, which later expands pushes the condensate to the opening intervals of 9 producing wells. The pressure in the process of gas condensate displacement is maintained at the maximum condensation pressure level. Otherwise, as can be seen from the condensation isotherms in FIGS. 2-5, the liquid phase can transition to the gaseous phase with direct evaporation - in the case of a decrease in pressure below the maximum condensation pressure or in retrograde evaporation if the pressure created by the pressure exceeds the maximum condensation. Therefore, the pressure in the process of displacing the condensate with dry gas is maintained at the pressure level of maximum condensation. After the full development of the condensate-saturated part, the deposit is developed as a purely gas one. To do this, through all the opening intervals of production wells, a selection of previously pumped gas is taken from the reservoir.

List of references

1. Mirzadzhanzade A.Kh. Theory and practice of gas condensate field development. M., Gostoptekhizdat, 1962, p.143.

2. Mirzadzhanzade A.Kh. Theory and practice of gas condensate field development. M., Gostoptekhizdat, 1962, p. 193-201.

3. Mirzadzhanzade A.Kh. Basics of gas production technology. M., Nedra, 2003.

Claims (3)

1. A method of developing a gas condensate reservoir, including drilling it with wells, pumping a dry hydrocarbon gas into the reservoir of the working agent, and selecting reservoir fluids, characterized in that the tubing operating the reservoir is provided with alternating magnetic field emitters, and the wells are provided with double completion with two opening intervals - upper and lower, while the development of the deposit is carried out in two stages, and at the first stage in the reservoir create an alternating magnetic field due to the drive of radiation It’s possible to select reservoir fluids through both wells opening intervals with reservoir development in the mode of reservoir energy depletion, while dry hydrocarbon gas is injected at the second stage of development, after reaching the maximum condensation pressure, in the upper opening intervals of the wells, and formation fluids are selected - the condensate deposited in the liquid phase is produced from the lower opening intervals. 2. The method of developing a gas condensate reservoir according to claim 1, characterized in that the maximum condensation pressure is determined by the condensation isotherms constructed from samples of reservoir fluids taken from this particular reservoir. 3. The method of developing a gas condensate reservoir according to claim 1, characterized in that the reservoir pressure is maintained at the maximum condensation pressure in the process of displacing the precipitated condensate with dry gas.

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