RU2753721C1 - Method for removing liquid from wells and bhz by hydropneumatic swabbing - Google Patents

Abstract

FIELD: oil and gas mining.

SUBSTANCE: invention relates to the development of oil, gas and gas condensate fields, namely, to a method for removing liquid accumulated during operation in the bottom-hole zone of the formation. To implement a method for removing the accumulated or injected liquid from the bottom-hole zone of the formation (BHZ) and the borehole, the accumulated or injected liquid present in the pump and compressor pipe (the tubing) is cut off with a piston. The specified liquid is displaced to the surface by a piston and the technological sludge of the well is carried out in order to restore the level in the borehole due to the inflow of liquid from the BHZ. As a piston, a column of a gas-liquid mixture, GLM, is used, formed in the tubing by feeding GLM from the surface through the inter-tube space and the tubing shoe. The GLM column is displaced to the surface together with the cut-off liquid by compressed gas supplied to the inter-tube space.

EFFECT: providing the possibility of displacing the borehole fluid with a piston, which is a column of GLM, forced by compressed gas.

1 cl, 6 dwg

Description

The invention relates to the development of oil, gas and gas condensate fields, namely to a method for removing fluid accumulated during operation in the bottomhole formation zone - bottomhole formation zone and wellbore, or fluid injected in the technological process, for example, well killing fluid, hydrochloric acid treatment reaction products etc.

Closest to the proposed method of oil production according to RF patent No. 2268354 (op. 20.01.2006), including periodic pumping of oil, characterized in that pumping oil is performed by swabbing with oil pouring into a mobile container, swabbing is carried out with gas bypass from the space above the swab to the annular space of the well, while the rate of decrease in the liquid level in the well is maintained no more than the rate at which a pressure is created at the bottomhole, which is less than the oil degassing pressure.

The prototype method is not efficient enough, reliable and environmentally friendly. In particular, the prototype method cannot be applied to wells where the inner surface of the tubing - tubing has technological contractions (pressure seats, salt and ARPD deposits, etc.); in wells with a deviated or horizontal wellbore; in deep wells more than 3,000 meters due to the significant time of lifting the swab; not applicable for gas and gas condensate wells due to the specifics of their operation. Efficiency - the efficiency of the prototype method is low due to significant leaks of the lifted fluid between the swab-piston and the inner surface of the tubing, which entails a long-term swabbing process.

Insufficient reliability of the prototype method is associated with the likelihood of accidents due to jamming of the swab-piston and cable breakage. Also, the prototype method is not environmentally friendly due to the possibility of leaks through the cable gland device.

The problem to be solved and the expected technical result consists in the development of a highly efficient, reliable, trouble-free and environmentally friendly method of lifting fluid from the bottomhole to the surface at any wells: oil, gas, gas-condensate; possibly having inclined or horizontal sections of wells, including deep wells more than 3,000 meters, by ensuring the lifting and removal of fluid accumulated during operation in the bottomhole formation zone and the wellbore, or fluid injected in the technological process, without the use of any downhole equipment and with 100% efficiency due to the absence of leaks in the lifted and removed liquid. The technical result consists in ensuring the operating conditions in the proposed set of operations of the gas-liquid mixture - GZhM - as a piston displacing to the surface the liquid accumulated during operation in the bottomhole formation zone and the wellbore, or the liquid injected in the technological process, for example, killing fluid.

The problem is solved by the fact that the proposed method for removing accumulated or injected fluid from the bottomhole formation zone - bottomhole formation zone and wellbore in order to restore the level in the wellbore due to the inflow of fluid from the bottomhole formation zone, it differs in that a column of a gas-liquid mixture is used as a piston - a gas-liquid mixture formed in the tubing by feeding a gas-liquid mixture from the surface through the annular space and a tubing shoe, after which the column of gas-liquid mixture is displaced to the surface together with the cut-off liquid by the compressed gas supplied to the annular space.

A finely dispersed structured GZhM is used, preferably obtained by the method according to the patent of the Russian Federation No. 2553105.

The proposed method for removing fluid from wells and bottomhole formation zone by hydropneumatic swabbing is illustrated by Figures 1-6 and is carried out by the following sequence of operations.

1. Injection line 1 is connected to the annulus of the well with accumulated or previously injected fluid (for example, killing fluid), and flow line 2 is connected to the tubing outlet for disposal of the accumulated or previously injected fluid being removed - FIG. 1; here and in all other figures (except Fig. 5), the position of the accumulated or previously injected fluid in the tubing and the annular space of the well is shown in light gray.

2. The calculated volume of a finely dispersed structured GZHM (approximately equal to the volume of the tubing) is injected into the injection line - Fig. 2, where the direction of injection of the wellbore is shown with a dark gray arrow. FIG. 2 and all other figures (except for Fig. 1 and Fig. 6), the position of the HGM in the tubing and the annular space of the well is shown in dark gray.

3. The volume of liquid-liquid mixture pumped into the annular space is forced through the tubing shoe into the inner cavity of the tubing with compressed gas, for example, nitrogen, thereby forming a column of liquid-liquid mixture in the tubing, cutting off the volume of the lifted liquid in the tubing, located above the formed column of liquid-liquid mixture - Fig. 3, where the direction of injection of compressed gas is shown by a white arrow. FIG. 3 and subsequent FIGS. 4-6 the position of the compressed gas in the tubing and the annular space of the well is shown in white.

4. The compressed gas continues to be pumped into the annular space, which leads to the displacement of the well fluid to be removed from the tubing to the surface by means of the GJM column formed in the tubing (acting as a piston) - FIG. 4, where the direction of injection of the compressed gas is shown with a white arrow (the position of the compressed gas in the annulus and tubing is shown in the same color), and the direction of the withdrawal of the accumulated or previously injected liquid to be removed is shown with a light gray arrow (the position of the removed liquid in Fig. 4 and other figures).

5. Further injection of compressed gas into the annular space ultimately leads to the displacement from the tubing to the surface - following the removed borehole fluid - a column of gas-liquid mixture (acting as a piston) - Fig. 5, where the direction of injection of compressed gas into the annulus is shown by a white arrow (the position of the compressed gas is also shown in white in Figs. Fig. 2-5).

6. The injection of compressed gas into the annular space is stopped and the well is opened to release the pressure and then set the level in the borehole (annular space and tubing) due to the inflow of fluid from the bottomhole formation zone - FIG. 6, where the directions of depressurization (discharge of previously injected compressed gas from the annulus and from the tubing are shown with white arrows (the position of the compressed gas is also shown in white in Figs. 3-6).

The described operations 1-6 are repeated until the accumulated liquid or unwanted fluid is completely removed from the bottomhole formation zone and the wellbore.

EXAMPLE OF A SPECIFIC IMPLEMENTATION OF THE METHOD

The oil well was shut down after major overhaul.

Geological and technical characteristics:

- artificial bottom hole 2791.6 m;

- production casing 168 mm;

- wall thickness of the e / column 12.06 mm;

- perforation interval 2677-2681.6 m;

- reservoir pressure 8.42 MPa;

- lift: tubing 73 mm with equipment for gas lift;

- elevator descent depth 2694.3 m;

- static level 1740 m.

Equipment for the technological process

- pumping unit АЦ-32;

- nitrogen compressor SDA-20/251;

- plug-in wellhead equipment for path generation of gas-liquid mixture (GZhM);

- topping up container with an aqueous solution of surfactant 0.3%;

- waste liquid receiving tank.

Technological process

- mounted and pressurized the injection line with plug-in wellhead equipment and knocked it out to the annular space;

- the flow line from the tubing was mounted and tied to the receiving tank;

- opened the central and annular valves located on the wellhead;

- with the compressor and pumping unit running with a flow rate of 2.5 l / s, 8 m ^{3 of the} working gas mixture was pumped;

injection pressure parameters (initial, operating and final, respectively) were:

P _start = 7.0 MPa, P _slave = 4.0 MPa, P _end = 2.5 MPa;

- the pumping unit was stopped;

- pushed through with compressed nitrogen a pack pumped into the annulus through the "shoe" in the tubing, thereby forming a GJM column in the tubing, cutting off the volume of the well fluid being lifted in the tubing, located above the formed GJM column;

- the specified punching with compressed nitrogen was carried out until the exit of the well fluid from the flow line and the termination of the removal of the liquid phase of the well fluid;

- the selected sample was a light translucent liquid. Preliminary: killing fluid.

Next, the above operations were repeated:

- with the compressor and pumping unit running with a flow rate of 2.5 l / s, 8 m ^{3 of} gas mixture was pumped in;

injection pressure parameters were:

R _start = 3.0 MPa, R _slave = 3.0 MPa, R _end = 3.5 MPa;

- the pumping unit was stopped;

- pushed through the pack of gas mixtures with compressed nitrogen until it exits the flow line into the receiving container.

The exit of the well fluid through the tubing space into the receiving tank during the operation of the compressor unit lasted for two hours; for the first 40 minutes, the borehole fluid came out impulsively, then steadily, into a full pipe.

- the taken sample was a turbid translucent liquid with a 5 mm black film on the surface and a characteristic smell of oil gas. Preliminary: oil and well killing fluid with formation water;

- the injection of compressed nitrogen was stopped for 4 hours to accumulate the inflow of process and formation fluid from the bottomhole formation zone in the wellbore, for which the injection and flow lines were opened into the atmosphere with the central and annular valves open, providing pressure relief and subsequent leveling in the wellbore (annular space) and tubing due to the inflow of fluid from the bottomhole formation zone.

Then the third repetition of the above operations was performed:

- with open annular and central valves, with the compressor and pumping unit running, with a flow rate of 2.5 l / s, 8 m ^{3 of} gas mixture was pumped in;

parameters of injection pressure of gas-liquid mixture:

P _start = 2.3 MPa, P _slave = 5.0 MPa, P _end = 3.5 MPa;

- the pumping unit was stopped;

- pushed a pack of gas-liquid mixtures with compressed nitrogen until it exited the flow line into the receiving tank together with the removed borehole fluid. Extraction of well fluid through the tubing into the receiving tank with compressed nitrogen with open annular and central valves continued continuously for 6 hours. The nature of the well fluid production remained stable, which indicates the normal operation of the well in the gas-lift mode.

объема состояли из жидкости темного цвета со светлым отстоем на дне и характерным запахом нефтяного газа. Предварительно: нефть и пластовая вода.Several samples of liquid removed from the well were taken. All samples for

volumes consisted of a dark liquid with a light sediment at the bottom and a characteristic smell of oil gas. Preliminary: oil and formation water.

The volume of fluid extracted from the well for the entire technological process was 54 m ³ .

After dismantling the plug-in wellhead equipment and piping the wellheads with injection and receiving lines, the well was put into operation using the gas-lift method.

Thus, the effectiveness of the method is ensured by the fact that in the proposed set of operations, the wellbore fluid functions as a piston displacing to the surface the fluid accumulated during operation in the bottomhole formation zone and the wellbore, or the fluid injected in the technological process, for example, killing fluid.

The proposed method is highly efficient, reliable and environmentally friendly, as it is not prone to accidents. Suitable for lifting fluid from the bottomhole to the surface on any wells: oil, gas, gas-condensate; possibly having inclined or horizontal sections of wells, including deep wells more than 3,000 meters, by ensuring the lifting and removal of fluid accumulated during operation in the bottomhole formation zone and the wellbore, or fluid injected in the technological process, without the use of any downhole equipment and with 100% efficiency due to the absence of leaks in the lifted and removed liquid.

Claims (2)

1. A method for removing accumulated or injected fluid from the bottomhole formation zone - bottomhole formation zone and wellbore, including cutting off the accumulated or injected fluid present in the tubing - tubing with a piston, displacing said fluid to the surface by a piston and process sludge of the well in order to restore the level in the wellbore wells due to the inflow of liquid from the bottomhole formation zone, characterized in that a column of gas-liquid mixture is used as a piston - a gas-liquid mixture, formed in the tubing by feeding a gas-liquid mixture from the surface through the annular space and a tubing shoe, after which the column of gas-liquid mixture is displaced to the surface together with the cut-off liquid by compressed gas, supplied to the annular space. 2. The method according to claim 1, characterized in that a finely dispersed structured GGM is used.

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