RU2804653C2 - Method for gas production in a watered gas well by periodically removing formation water from the bottom hole into the underlying water-saturated formation - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: eliminate the problem of the water cone formation and, as a result, self-kill. Periodic removal of water accumulated at the bottom hole is carried out into the underlying water-saturated formation while maintaining bottom hole pressure, opening the underlying water-saturated part of the formation 10-15 meters below the level of gas-water contact (GWC). Running tubing, below which the assembly is suspended with an installed inverted electric screw pump, a mechanical packer below the water inlet module, an electric shut-off valve, a gas inlet filter, a water inlet module, a check valve to prevent the flow of liquid back into well, an automatic control system, an absolute pressure sensor under the electric shut-off valve, an absolute pressure sensor at the inlet to the inverted screw pump, an absolute pressure sensor at the outlet of the inverted screw pump. Activation of the mechanical packer by turning the tubing, completion of the well and putting the well into operation, waiting for the accumulation of a sufficient amount of water above the mechanical packer, automatic processing at the control station of the readings of the absolute pressure sensors installed under the electric shut-off valve and at the inlet to the inverted screw pump types, the difference between which is a parameter for regulating the operation of the pump and is equal to the volume of water accumulated above the mechanical packer, receive an output signal from absolute pressure sensors that measure the volume of water by pressure drop, and transmit the indicated signal to the controller, which analyzes the received data and makes a decision about turning on or off the inverted screw pump. Produce the pumping of the accumulated formation water from the bottom and its subsequent injection into the underlying aquifer.

EFFECT: shutdown of the inverted screw pump after pumping out and injection of the volume of water determined by the pressure drop between the absolute pressure sensors under the electric shut-off valve and at the inlet to the screw pump, which ensures the extension of the life cycle of the well by periodically removing the accumulated water at the bottom and pumping it into the underlying water-saturated formation while maintaining bottom hole pressure.

1 cl, 4 dwg

Description

The present invention relates to the oil and gas industry and is intended to eliminate the problem of the formation of a bottom water cone and, as a consequence, self-squeezing of gas wells.

The development of thin gas formations with active bottom water is complicated by the formation of a water cone in the early stages of operation, rapid breakthrough of formation water into the production well and self-squeezing of the well. The problem of self-damping of a well is solved by stopping operation (mothballing the well) or by blowing out the well.

There is a known method of waterless well operation [RF Patent No. 2333348, 2008, IPC E21B43/00 E21B43/32], which consists in creating a waterproofing screen in the formation during the operation of gas and gas condensate wells equipped with production and lift strings, using the injection of a water-repellent composition into the formation under pressure without killing the well.

Significant disadvantages of this method include additional financial costs for periodic descent of coiled tubing, the likelihood of loss of gas injected to maintain pressure in the annulus and annular spaces, and the influence of the time of year on the frequency of use.

There is a known method for lifting heterogeneous multiphase products from a well and a device for its implementation [Patent RU 2683463, 2019, IPC E21B 43/00 F04F 5/54 F04D 15/00], which consists in pumping products from the formation, partial separation of free gas from liquid, followed by the entry of a gas-liquid mixture into the pump and its injection into the nozzle of the jet apparatus, the pumping of the well product from the annulus and from the bottom into the tubing by the jet apparatus, and the lifting of the product to the surface.

Significant disadvantages of the method under consideration include large pressure losses of the gas-liquid mixture due to local resistances (constrictions in the check valve, jet apparatus and tubing string), increased operating costs for the disposal of water raised to the surface, and the appearance of additional energy costs for raising water to the wellhead.

There is a known method for extracting gas from a flooded gas formation, which consists of pumping the water accumulated at the bottom from the perforations of the gas-saturated part of the formation with an inverted electric centrifugal pump (ESP) and pumping the pumped water into the absorbing aquifer (below the gas formation) through the perforations of the aquifer interval. To isolate the gas-bearing and aquifer formations, a packer is used, equipped with a device for connecting a pump; a check valve is used to prevent water from entering the engine (Operation of flooded gas wells. Technological solutions for removing fluid from the well, James Lee, Henry Nickens, Michael Wells, Premium LLC Engineering", 2008, UDC 622.324 (035), BBK 33.361ya2).

A significant disadvantage of the method is its limited functionality, since the method is applicable in wells in which there is a low gas content and a significant depth of the absorption layer relative to the wellhead.

The closest technical solution adopted for the prototype is the method of gas production from the flooded formation [Patent RU 2729548, 2020, IPC E21B 43/00], which includes lowering a tubing string into the flooded well with the installation of two packers opposite the boundaries of the absorbing formation (between the mouth and gas-saturated part of the well) to isolate the annulus and a controlled valve for hydraulic communication of the tubing string with the annulus of the well opposite the absorption formation, lowering an inverted pumping unit on a load-carrying cable to the bottom of a flooded well, piping the wellhead with a gas line, closing the gas line, turning on the pumping unit , opening the controlled valve, lifting the formation water along the tubing string into the absorbing formation, closing the controlled valve, turning off and lifting the inverted pumping unit, opening the gas line and extracting gas from the gas formation freed from the formation water.

Significant disadvantages of the prototype include material and time costs for hoisting operations when lowering and lifting an inverted pumping unit, and the lack of an automated control system.

The objective of the present invention is to develop a method for gas production in a flooding gas well, ensuring extension of the life cycle of the well by periodically removing water accumulated at the bottom and pumping it into the underlying water-saturated formation while maintaining reservoir pressure.

When implementing the invention, the problem is solved by achieving a technical result, which is to increase the efficiency of gas production by removing the formation water entering the well through the perforations by pumping it back into the formation using an inverted-type pump arrangement with an installed electric screw pump (EVP) ), which will avoid self-squeezing of the well (a drop in reservoir pressure with further shutdown of the well) and extend the life cycle of the well.

The technical result when using the invention will be the removal of formation water entering the well through the perforations by pumping it back into the formation through the use of an arrangement with an inverted type pump with an installed electric screw pump (ESP), which will avoid self-squeezing of the well (a drop in formation pressure with further shutdown wells) and extend the life cycle of the well.

The objective and technical result are achieved by the fact that the method of gas production in a water-saturated gas well by periodically removing formation water from the bottom into the underlying water-saturated formation includes drilling a gas production well, opening the gas-saturated part of the formation, opening the underlying water-saturated part of the formation 10-15 meters below the gas-water level contact (GWK), lowering the production string 10-15 meters below the GWK, perforation of the gas-saturated interval and perforation of the water-saturated interval, which is carried out below the GWK by 10-15 meters, lowering of tubing, below which an arrangement with an inverted type pump with an installed electric screw pump is suspended (EVN), waiting for the swelling of the packer, which is located 5-10 meters below the GWC, serving to accumulate water entering the well and pumping it back into the water-saturated part of the formation, waiting for the swelling of the packer, which is located above the GWC on the tubing, serving to prevent water from entering behind the tubing, development of the well through the perforation of the gas-saturated interval and bringing the well into operation mode, waiting for the accumulation of a certain amount of water above the packer, which is located 5-10 meters below the GWK (It has been empirically determined that at this distance the pump will not run idle), turning on the pump using an automated control system located at the mouth of a gas production well, pumping out accumulated formation water from the bottom and pumping it into the underlying aquifer, turning off the pump after pumping and pumping a certain volume of water (the pump is turned on and off periodically to increase the service life of the EWH) .

In the proposed method of extracting gas from flooded gas wells, it is priority to use an electric screw pump, since it is designed to work with a fairly high gas content of 80–90%, and is also resistant to mechanical impurities. Depending on the anisotropy of the formation permeability and the flow rate of produced formation water, according to the pressure characteristics of the pumping units, the optimal supply and the corresponding EHP are selected, which will pump water back into the water-saturated part.

The method is illustrated with illustrative materials, where:

in fig. Figure 1 schematically shows gas-saturated and water-saturated formations drilled by a well, where the numbers indicate: 1 – well; 2 – bit; 3 – gas-saturated formation; 4 – water-saturated formation; 5 – production string; 6 – cement mortar; 7 – perforation of gas-saturated formation; 8 – perforation of a water-saturated formation;

in fig. Figure 2 schematically shows the downhole equipment that is necessary to remove water from the bottom of the well, where the numbers indicate: 9 – tubing string; 10 – electrical power cable for the shut-off valve; 11 – shut-off valve; 12 – power cable for the electric motor; 13 – filter for gas production; 14 – upper hydraulic protection module of the electric motor; 15 – electric motor; 16 – lower hydraulic protection module of the electric motor; 17 – input module for water supply; 18 – inverted pump; 19 – mechanical packer; 20 – check valve;

in fig. Figure 3 schematically shows the process of pulling a cone of water towards the perforations and its accumulation in the space above the packer, where the numbers indicate: 7 – perforation of a gas-saturated formation; 21 – cone of bottom water; 4 – water-saturated formation; 8 – perforation of a water-saturated formation.

in fig. Figure 4 schematically shows the process of removing water from the bottom of a well and injecting it into a water-saturated formation, where the numbers indicate: 22 – absolute pressure sensor under the shut-off valve; 23 – absolute pressure sensor at the inlet to the inverted pump; 24 – absolute pressure sensor at the outlet of the inverted pump; 25 – control station, which performs the functions of ensuring the technological operating mode of the well, ensuring the technological operating conditions of the EWH, processing all information that comes from absolute pressure sensors 22 and 23.

The method is implemented as follows

In the process of drilling a gas production well 1 with a bit 2, the gas-saturated part 3 of the formation is opened, as well as the underlying water-saturated part 4 of the formation is opened 10 - 15 meters below the gas-water contact (GWC) (Fig. 1), since this provides the necessary volume of free space for accumulations of water, which is 0.17 cubic meters. It has been empirically deduced that at a given distance between the perforation for gas production and the perforation for water injection, a volume of water will accumulate at which the most effective water removal will be ensured.

The production string 5 is lowered over the entire interval of the gas-saturated 7 and water-saturated 8 parts of the formation.

The cement solution 6 is pumped into the production string 5.

The gas-saturated 7 and water-saturated 8 parts of the formation are perforated (Fig. 1).

On the tubing string 9, an assembly is lowered to the bottom of the well through the production string, which contains the following assembly elements located sequentially from top to bottom , an electric shut-off valve 11, which is used to shut off the internal space of the tubing and shut down the well; absolute pressure sensor under the electric shut-off valve 22; filter for gas production 13 without bringing rock to the surface; upper hydraulic protection module 14 of the electric motor; electric motor 15; lower hydraulic protection module 16; input module 17 for water supply, which is a filter to prevent the ingress of large amounts of mechanical impurities; absolute pressure sensor 23 at the inlet of the inverted pump; inverted screw pump 18, which can be used as an electric screw pump; mechanical packer 19, which is installed below the GWK at 5-10 meters and is activated by axial rotation of the tubing string 9; an absolute pressure sensor 24 at the outlet of the inverted pump and a check valve 20, which is necessary to prevent the reverse flow of injected water into the water-saturated formation (Fig. 2).

The operation of the well begins and the subsequent pull-up of the cone of water 21 to the perforations of the gas-saturated part 7 of the formation (Fig. 3).

After a sufficient amount of water has accumulated above the mechanical packer 19, which serves to accumulate water (the volumes of this water are recorded using the pressure difference between two absolute pressure sensors, one 22 is located under the electric shut-off valve, the other 23 at the inlet of the inverted screw pump type, measuring pressure at the appropriate points), the automatic control system turns on the electric motor 15 and the inverted screw pump 18, all the accumulated water begins to flow into the input module 17, which is pumped back into the water-saturated part of the formation 4, which is located below the GWC, by the inverted screw pump 18 at 10-15 meters. In addition, gas enters filter 13, thereby gas production does not stop (Fig. 3). The automatic control system is built on the following operating principle - absolute pressure sensors 22 and 23 continuously measure pressure values and convert the resulting value into a unified DC output signal, then the signal is transmitted to the control station 25, and then to the controller, where the difference in the readings of the two absolute sensors is calculated pressures 22 and 23. Next, the controller analyzes the data and makes a decision to turn on/off the EWH. The EWH is turned on/off periodically. If the EWH is operated constantly, there will be moments of idle operation without water. Because of this, the EWH may burn out. And the absolute pressure sensor 24 measures the pressure in the space under the packer, where water is injected into the water-saturated formation.

Next, the electric motor 15 is turned off, since all the water is removed back into the water-saturated part of the formation 4 and gas production continues until a certain amount of water accumulates above the mechanical packer 19 again (Fig. 4).

Thus, the claimed method for removing water from the bottom of a gas well, through the use of an arrangement with an inverted screw pump and periodic switching on/off of an electric motor, makes it possible to effectively remove water from the bottom of a well by injecting it into a water-saturated formation.

Claims (1)

A method of gas production in a flooded gas well by periodically removing formation water from the bottom into the underlying water-saturated formation, characterized in that the periodic removal of water accumulated at the bottom is carried out into the underlying water-saturated formation while maintaining formation pressure and includes opening the underlying water-saturated part of the formation by 10 -15 meters below the level of the gas-water contact (GWC), lowering the production casing over the entire interval of the gas-saturated and water-saturated parts of the formation, perforation of the water-saturated part of the formation, lowering tubing pipes, below which an assembly with an installed inverted electric screw pump, a mechanical packer below the inlet, is suspended module for water, an electric shut-off valve designed to shut off the internal space of the tubing and stop the well, a filter for gas inlet, an inlet module for water inlet, a check valve to prevent the flow of liquid back into the well, an automatic control system, an absolute pressure sensor under an electric shut-off valve, an absolute pressure sensor at the inlet of an inverted screw pump, an absolute pressure sensor at the outlet of an inverted screw pump, activation of a mechanical packer by turning the tubing, which is located 5-10 meters below the GWK, which serves for accumulation water entering the well and pumping it back into the water-saturated part of the formation, development of the well through perforations of the gas-saturated interval and bringing the well into operation mode, waiting for the accumulation of a sufficient amount of water above the mechanical packer, automatic processing at a control station installed on the surface to regulate the operation of the well, readings from absolute pressure sensors installed under the electric shut-off valve and at the inlet to the inverted screw pump, the difference between which is a parameter for regulating the operation of the inverted screw pump and is equal to the volume of water accumulated above the mechanical packer, the output signal is received from the absolute pressure sensors, measuring the volume of water by pressure difference, and transmit the specified signal to the controller, which analyzes the received data and makes a decision to turn on or off the inverted screw pump, pump out the accumulated formation water from the bottom and its subsequent injection into the underlying aquifer, turn off the inverted screw pump type after pumping out and pumping a volume of water determined by the pressure difference between the absolute pressure sensors under the electric shut-off valve and at the inlet of the inverted screw pump, turning the inverted screw pump on and off occurs periodically to increase the service life of the inverted screw pump.