RU2797149C1 - Method for separate examination of two formations in their simultaneous and separate operation by one well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the production, research and regulation of production from two reservoirs in one well. The method for separate testing of two formations during their simultaneous and separate operation by one well includes separation of the formations by a packer, extraction of products from a more oil-bearing formation by a submersible pump along a column of lift pipes with pressure control at the pump inlet, and short-term periodic extraction of products from another formation as fluid accumulates. The reservoir products are extracted with separate control of their water cut. At the same time, wells are selected where the more oil-bearing formation is the lower one. After installing the packer and lowering the pump on the lift pipes, a pipe is lowered into the annulus of the lift pipes, followed by sealing the wellhead with wellhead fittings. The lower end of the pipe is placed between the upper formation and the packer. The products from the upper formation are taken by injection of air from the wellhead into the annulus of the lift pipes until the air exits the wellhead from the pipe. The measure of oil accumulation in the upper formation is restoration of the liquid level in the annulus of the lift pipes after extraction. The performance of the upper formation is determined by the liquid level recovery curve.

EFFECT: expansion of functionality and simplification of the method for implementing a separate examination of two formations during their simultaneous and separate operation by one well.

2 cl, 2 dwg

Description

The invention relates to the oil and gas industry, namely to the production, research and regulation of production from two reservoirs with one submersible pump.

A known method for separate measurement of production during simultaneous-separate operation of a well equipped with an electric centrifugal pump (patent RU No. 2567249, IPC E21V 47/10, E21V 43/12, publ. branch pipe passing through the packer separating the layers, its flow in a mixture with the production of the upper layer from the above-packer zone of the well to the pump intake, measurement of the total fluid flow rate and its water cut on the day surface, measurement of the intake pressure and pump operation parameters using the telemetric system module, installed under the submersible electric motor of the pump, measuring the pressure at the bottomhole of the lower formation using a downhole pressure gauge connected by a cable to the telemetric system module, shutting off the production of one of the formations using a hydraulic packer with pressure transmission through a small diameter tube to measure the parameters of another formation, determining flow rates of oil and water of the overlapped formation by subtracting from the total production rates of oil and water of the well the flow rates of the operating reservoir, and measurements of the overlap of the formation with a lower oil production rate are carried out by lowering the load into the lower part of the tubing string, which opens due to its own weight the access of high-pressure fluid from pipe strings through a small-diameter pipe into a hydraulic packer, and after shutting off the formation, the speed of the submersible motor is reduced by the frequency converter of the electric drive to maintain the pressure at the pump intake equal to the pressure before shutting off the formation, after which oil and water flow rates are measured on the day surface.

The disadvantages of this method are a narrow scope due to the possibility of working only with an electric pump unit with a variable frequency drive (VFD) and the complexity of implementation due to the need for lifting operations of the load to open the side hole, while there are large time non-production costs associated with the need to stop the extraction of products during measurements.

The closest in technical essence is the method of oil production from multilayer wells with an electric submersible pumping unit (patent RU No. 2686796, IPC E21V 43/14, E21V 43/12, publ. 04.30.2019 Bull. No. 13), including the alternation of short-term pumping and accumulation oil in the well with regulation of the performance of the electric pump in accordance with the flow rate of the well and pressure by changing the speed of the electric drive of the pump to an efficiency of at least 0.9 for a given speed, and short-term pumping of oil is carried out from one or more oil-bearing horizons simultaneously with its accumulation on others horizons of a multi-layer well, separated by packers, alternating oil-bearing horizons by periodically switching their opening to closing and vice versa by electric gates as oil accumulates in the well during continuous operation of a frequency-controlled electric drive pump with capacity control in accordance with the flow rate of oil-bearing horizons and pressure in the well, determined by sensors instrumentation, wherein the duration of accumulated oil pumping out from some horizons is integrated with the duration of oil accumulation in other oil-bearing horizons, which is no more than 0.95 of the duration of short-term pumping, up to a pressure that determines the volume of accumulated oil exceeding the minimum filling level of the tubing string.

The disadvantages of this method are the narrow scope due to the possibility of working only with an electric pump unit with a variable frequency drive (VFD) and the complexity of implementation due to switching to the opening of one layer and closing the rest with electric gates with regulation of the pumping unit's performance in accordance with the flow rate. oil-bearing horizons, while there are large time non-production costs associated with the need to stop production when switching between reservoirs, and a decrease in the resource of the pumping unit (with a 2-fold drop in productivity, which occurs very often between reservoirs, while maintaining the coefficient of performance (COP) pumping unit is not lower than 0.9, the overhaul period is reduced by more than 2 times).

The technical objective of the proposed invention is to create a method for separate testing of two layers during their simultaneous-separate operation of a well by one well, which allows expanding functionality and simplifying implementation through the use of any submersible pumps without adjusting the performance and without shutting off production when testing the upper layer.

The technical problem is solved by the method of separate study of two reservoirs during their simultaneous-separate operation of the well by one well, including separation of the reservoirs by a packer, selection of production from a more oil-bearing formation by a submersible pump through a column of lift pipes with pressure control at the pump inlet and short-term periodic selection of production from another reservoir along to the extent of fluid accumulation, and the selection of reservoir products is carried out with separate control of the water cut of their products.

What is new is that wells are selected where a more oil-bearing formation is lower, after installing the packer and lowering the pump on the lift pipes into the annulus of the lift pipes, the pipe is lowered, followed by sealing the wellhead with wellhead fittings, the lower end of the pipe is placed between the upper formation and the packer, selection products from the upper layer are injected from the mouth of the air into the annulus of the lift pipes until the air exits at the wellhead from the pipe, and the measure of the accumulation of oil in the upper layer is the recovery of the liquid level in the annulus of the tubing after extraction, and the productivity of the upper layer is determined by the liquid level recovery curve .

It is also new that the pipe is connected to the wellhead with a removable connection.

In FIG. 1 shows a diagram of the bottomhole zone of a well with a tube.

In FIG. 2 shows a diagram of the bottomhole zone of the well with the tool.

Structural elements, seals, process connections, valves that do not affect the implementation of the method, in the drawings (Fig. 1 and 2) are not shown or are shown conditionally.

The method of separate study of two layers 1 (Fig. 1 and 2) and 2 during their simultaneous-separate operation of well 3 by one well with a submersible pump 4 (rod pump - SRP, electric centrifugal pump - ESP, gerotor pump - GRN or the like, that is, any pump with the required capacity), including the separation of layers 1 and 2 by packer 5, the selection of products from a more oil-bearing lower layer 1 by a submersible pump 4 along a string of tubing pipes 6 with pressure control by a sensor (not shown - the author does not claim to design and mount the sensor ) at the inlet of pump 4 and short-term periodic selection of products from another - upper layer 2 as liquid accumulates (oil, water). The production of formations 1 and 2 is sampled with separate control of the water cut of their production by sampling and analyzing the production of each of the formations 1 or 2. After installing the packer 5 and lowering the pump 4 on the lift pipes 6 into their annulus 7 (Fig. pipe 8 with subsequent sealing of the wellhead with wellhead fittings (not shown - its author does not claim contraction). The lower end 9 of the tube 8 is placed between the upper formation 2 and the packer. The selection of products from the upper layer 2 is carried out by pumping air from the mouth with a compressor (not shown) into the annulus 7 of the lift pipes 6 until the air exits at the wellhead 3 from the pipe 8. The measure of accumulation of oil from the upper layer 2 is the recovery (stopping growth) of the liquid level 10 in the annulus 7 lift pipes 6 after product selection by air injection. Liquid level control 10 can be carried out with the mouth echo sounder, laser rangefinder (not shown) or the like. - The author does not claim this. The productivity of the upper layer 2 is determined by the recovery curve of the level 10 of the liquid (formation production) - KVU. For a more detailed control over the condition of the equipment (pump 4, packer 5, etc.), the walls of the well 3 above the packer 5 and / or the content of the production of the upper layer 2, the pipe 8 is connected to the wellhead with a removable connection with the possibility of replacement with a downhole tool 11 ( Fig. 2) with appropriate sensors (not shown), lowered into well 3 on a geophysical cable 12, and to replace the tube 8 or device 11 (Fig. 2) with others, respectively, or during downtime for oil accumulation - with a sealed plug (not shown), blocking the communication with the annulus 7 of the well 3.

An example of a specific implementation.

Well 7385 NGDU "Yamashneft" at the field of the Republic of Tatarstan (RT) opened two layers: the lower 1 (Fig. 1 and 2) - the Devonian horizon and the upper 2 - the Buregsky horizon. The productivity (flow rate) of the upper reservoir 2 was less than 1 m ³ /day, which made it unprofitable to use any submersible pumps for it due to their long downtime to accumulate the products (oil) of this reservoir 2 in well 3. pass-through packer 5, which separated layers 1 and 2. After that, a submersible pump 4 (plug-in SRP - VSHGN) was lowered into the well on a column of lift pipes 6 until it was fixed and tightly interacted with the packer 5. Lift pipes 6 were fixed on a plan-washer (not shown ) at the wellhead 3 and installed a wellhead with a side channel parallel to the main channel (not shown), with which the lift pipes 6 are connected (see patents RU No. 2608096, 2483211, PM 134575 or the like). A pipe 8 (Fig. 1) was lowered into the side channel of the wellhead, a continuous flexible pipe with ø 28 mm, the lower end 9 of which was placed below the bottom of formation 2 in order to be guaranteed to be below the formation pressure level 10 of the upper formation 2. Upper edge (not shown) tubes 8 were hermetically fixed (the author does not claim to be connected) in the side channel of the wellhead fitting and connected to the oil pipeline (not shown). The annulus 7 of well 3 was communicated through an air valve (not shown) with an air compressor. The rods (not shown) of the pump 4 through a polished rod (not shown) were connected to the wellhead drive, under the action of which the pump 4 began to take the products of the lower layer 1 through the lift pipes 6 and then through the wellhead fittings into the oil pipeline. Air was pumped into the annulus 7 by an air compressor, squeezing out the products of the upper layer 2 through the pipe 8 and wellhead fittings into the oil pipeline, lowering the liquid level 10 in the annulus 7 until air burst through the lower edge 9 into the pipe 8, which was recorded by gurgling and increased noise at the wellhead 3, after which the air injection was stopped. The level of liquid 10 was controlled using a wellhead echo sounder (see patent RU No. 2282718 or the like), while building a KVU. With the help of KVU, the flow rate of the upper layer 1 is determined (see, for example, https://poznayka.org/s89273t1.html ). subsequent control of the level 10 without stopping the operation of the submersible pump 4, which selects the products of the lower layer 1.

After a long operation (6 months or more), the upper edge of the tube 8 was disconnected from the oil pipeline and wellhead fittings, after which the tube was removed from the side channel. A downhole tool 11 was lowered into the side channel of the wellhead equipment on a geophysical cable 12 (Fig. 2) to the packer 5. Data (indications) from the sensors of the tool 11 were transmitted to the surface via a geophysical cable for recording, storage and analysis. For more detailed monitoring of the condition of the equipment (pump 4, packer 5, etc.), the walls of the well 3, magnetic inclinometers, ultrasonic transmitters and receivers, or the like can be used as sensors of the tool 11. (the author does not claim this). Density meters, samplers, or the like can be used as sensors of the device 11 to analyze the state of the products of the upper layer 1. (the author does not claim this). If it is necessary to replace, repair or maintain the downhole tool 11 or tube 8 (Fig. 1), after their extraction, the side channel of the wellhead fittings was temporarily blocked with a sealed blind plug of the appropriate diameter. Periodically, at the wellhead 3, samples are taken from the tubing 6 or from the pipe 8 to analyze the watered production of the corresponding formations 1 or 2.

When implementing the method, it was not required to use any downhole equipment that was difficult to manufacture and use.

The proposed method of separate testing of two layers during their simultaneous-separate operation of a well by one well allows expanding the functionality and simplifying implementation through the use of any submersible pumps without adjusting the performance and without shutting off production during the study of the upper layer.

Claims (2)

1. A method for separate testing of two reservoirs during their simultaneous-separate operation by one well, including separating the reservoirs with a packer, sampling products from a more oil-bearing reservoir with a submersible pump through a column of tubing with pressure control at the pump inlet and short-term periodic sampling of products from another reservoir as it accumulates liquids, and the selection of reservoir products is carried out with separate control of the water cut of their products, characterized in that wells are selected where the more oil-bearing reservoir is the lower one, after installing the packer and lowering the pump on the lift pipes into the annulus of the lift pipes, the pipe is lowered, followed by sealing the wellhead wellhead fittings, the lower end of the tube is placed between the upper reservoir and the packer, the selection of products from the upper reservoir is carried out by injection from the mouth of the air into the annulus of the tubing until the air exits at the wellhead from the tube, and the measure of accumulation of oil from the upper layer is the restoration of the liquid level in the annulus of the tubing after selection, and the productivity of the upper layer is determined by the curve of recovery of the liquid level. 2. The method of separate study of two layers during their simultaneous-separate operation by one well according to claim 1, characterized in that the tube is connected to the wellhead fittings with a removable connection.

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