Method for flushing borehole pump filter

Abstract

FIELD: oil production industry.SUBSTANCE: invention relates in particular to technologies for restoring the functionality of borehole pumps. The method includes lowering an insert rod pump, equipped with a filter, into a well, stopping the well after the filter becomes clogged, raising the rod string to a height sufficient to disengage the pump from the lower support and raise the upper support relative to it with the formation of a concentric channel between the pump and the tubing for the flow of formation fluid from the tubing column into the well, installing the pump in the lower support and returning the well to operating mode. After shutting in the well, a cleaning agent is injected into the annulus in a volume of between 0 and 5 m3, the well operation is started for a period of time sufficient to fill the pump and filter with the cleaning agent (15 min), and shut down the well for a period of time sufficient to allow the cleaning agent to act on the solid mechanical particles on the filter and pump (30 min). After raising the rod string to a height sufficient to disengage the pump from the lower support and raise the upper support relative to it by 5 m, a cleaning agent is injected through the tubing in a volume equal to 2 well tubing volumes, then the pump is installed in the lower support, and returned to operating mode. The efficiency of cleaning the borehole pump filter is increased due to the uniform distribution of the cleaning agent, a waiting time sufficient for the cleaning agent to act on solid mechanical particles, and hydrodynamic treatment.EFFECT: increased efficiency of cleaning.1 cl, 2 dwg

Description

[0001] The invention relates to the oil production industry, in particular to technologies for restoring the operability of borehole pumping units when the filter is clogged with mechanical impurities and well deposits.

[0002] A method for underground repair of a production well and a plug-in pump for its implementation are known (patent RU No. 2190756 C1, IPC E21B 37 / 00, IPC F04B 47 / 02, published 10.10.2002, Bulletin No. 28), in which for underground repair of a production well caused by the failure of a plug-in pump, it is lifted on rods from the tubing left in the well, then another plug-in pump is lowered into the well on rods, the tightness of the seat of the detachable lock support is checked with washing fluid, filling the tubing with it to the wellhead, if necessary, the detachable lock support is lapped, then the plug-in pump is lifted until the detachable lock support opens, the dirt is washed out, accumulated in the shank, by flowing into the bottomhole of the drilling fluid poured into the tubing to check for leaks, while the insert pump contains a housing secured to the rods with its bottom part, the plunger is connected to the anchor mandrel of the detachable lock support, the anchor shoe of which is secured to the tubing,the suction valve is installed on the second end of the plunger, the discharge valve is located in the bottom part of the housing, the cam elements are made on the end surfaces of the housing and the anchor mandrel facing each other.

[0003] The disadvantage of this method is the low efficiency of flushing, as well as the long downtime of the well associated with the removal and diagnostics of the tubing at the pipe base, which entails a shortage of oil.

[0004] A method for cleaning a well equipped with an insert pump is known (patent RU No. 2707605 C1, IPC E21B 37 / 00, published on November 28, 2019, Bull.No. 34), which includes lowering into the well a column of tubing pipes with a liner and a locking support of an insert pump installed above the liner, lowering into the column of tubing pipes on pump rods with an anchor mandrel made with the possibility of hermetically sealed interaction with the locking support, raising the insert pump until the locking support opens and subsequent flushing of the liner and the well, wherein the bottom of the liner is located in the well at a level that ensures the most effective cleaning of the formation interval during flushing, also the column of tubing pipes before lowering above the locking support is equipped with an extension with an internal diameter that ensures a sufficient cross-sectional area with a pump located inside for flushing the well, and before flushing the insert pump is raised until it is located in the extension of the column of tubing pipes.

[0005] The disadvantage of this method is the frequent failure of the anchor mandrel, which does not allow flushing to be carried out in accordance with the approved method.

[0006] The closest in technical essence is the method of washing the filter installed at the intake of a borehole pump (patent RU 2531702 C1, IPC E21B 37 / 08, published 09 / 17 / 2013, Bulletin No. 30), which includes lowering a rod pump of an insert type into a sand-producing well, equipped with a filter at the intake, stopping the well after the filter is clogged with sand, partially raising the rod string by an amount sufficient to break the pump casing from the lock support and form a concentric flow channel between the pump casing and the tubing for the flow of liquid from the tubing string into the well, while the rod string is held in a raised position until the dynamic liquid level in the annulus of the well reaches a static position, after which the rod string is lowered to the initial position and The pump is started up.

[0007] The disadvantage of this method is the low efficiency of filter cleaning with dense colmatating deposits due to the lack of preliminary chemical action on the structure of the deposits, which reduces the effectiveness of mechanical cleaning.

[0008] The technical challenge is to increase the efficiency of washing the filter of a borehole pump through the action of a cleaning agent, partial well start-up and staged hydrodynamic treatment.

[0009] The technical problem is solved by a method of flushing a borehole pump filter, which includes lowering a rod pump of the insert type into the borehole, equipped with a filter at the intake, stopping the borehole after the filter is clogged with mechanical impurities and borehole deposits, raising the column of pump rods to a height sufficient to disengage the pump from the lower support and raise the upper support relative to it with the formation of a concentric channel between the pump and the tubing for the flow of formation fluid from the tubing column into the borehole, the pump is installed in the lower support and the borehole is returned to operating mode.

[0010] What is new is that the well is stopped for a time sufficient for the cleaning agent to act on the solid mechanical particles on the filter and pump, which is 30 minutes, and after lifting the column of pump rods, the cleaning agent is pumped through the tubing in a volume equal to 2 volumes of the well tubing, the pump is installed in the lower support and the well is returned to operating mode, while the height sufficient for disengaging the pump from the lower support is 5 m.

[0011] Fig. 1 shows a diagram of the implementation of the method before the disconnection of the insert pump from the lower support.

[0012] Fig. 2 shows a diagram of the implementation of the method after disengaging the insert pump from the lower support.

[0013] A tubing string 2 with a lower support 3 and a filter 4 at the lower end is lowered into well 1. A rod string 5 with an extended polished rod is used to lower a sucker rod pump 6 into tubing 2. The pump is equipped with a plunger 7, a suction valve 8, and a discharge valve 9. The housing of the rod pump is equipped with an upper support 10, which, together with the lower support 3, forms a locking support for the rod pump.

[0014] The method is carried out in the following sequence.

[0015] In the operating position (Fig. 1), the insert-type sucker rod pump 6 rests with its upper support 10 on the lower support 3 and transfers the weight of the sucker rod string 5 and the fluid to the tubing string 2. Formation fluid enters the well 1 through the filter 4, located at the intake of the insert-type sucker rod pump 6, being cleaned of mechanical impurities and wellbore deposits. Under the influence of the reciprocating movement of the plunger 7, the insert-type sucker rod pump 6 pumps the cleaned formation fluid to the wellhead 1 through the tubing string 2. During operation, the filter 4 is gradually clogged with mechanical impurities and wellbore deposits, which reduces its throughput.

[0016] The condition of filter 4 is monitored remotely at the wellhead of well 1 and is determined by any known method (e.g., by the shape of the dynamometer card, by a decrease in the productivity of the downhole pump, etc.). The authors do not claim this. If clogging is detected and a decision is made to carry out resuscitation work, well 1 is stopped and a cleaning agent (e.g., formation water + ML81b, formation water + MS20MPS, formation water + NEFTENOL-VKS) is injected through the annulus in a volume of 5 m 3, which promotes the destruction of adhesive, electrostatic, and chemical bonds between solid suspended particles on the surface of filter 4. Then, well 1 is put into operation, and filter 4 and insert-type pump 6 are filled with a cleaning agent. Well 1 is stopped for a period of time sufficient for the cleaning agent to act on the solid mechanical particles on filter 4 and insert-type pump 6, respectively, 30 minutes. During this time, the cleaning agent is evenly distributed inside and outside filter 4, actively breaking down deposits of solid suspended particles, which are subsequently easily removed by the flow of cleaning agent pumped through the tubing. Similar processes occur in the internal cavity of insert-type pump 6. Then, sucker rod column 5 is raised to a height sufficient to disengage insert-type sucker rod pump 6 from lower support 3, respectively, 5 m.In this case, the upper support 10 rises relative to the lower support 3, forming a concentric channel between the tubing string 2 and the insert-type sucker rod pump 6. The formation fluid located in the tubing string 2, under the influence of a high pressure drop, flows through the formed concentric channel and filter 4 back into the well 1 (Fig. 2), washing away the remains of mechanical impurities and well deposits and cleaning it. Next, to completely remove the remaining mechanical impurities and well deposits from the filter 4 and the insert-type pump 6, flushing is performed by pumping a cleaning agent (e.g., formation water + ML81b, formation water + MS20MPS, formation water + NEFTENOL-VKS) in a volume equal to 2 volumes of the well tubing 2, into the tubing string 2. Upon completion of flushing, the insert-type well pump 6 is installed in the lower support 3 and the well 1 is returned to operating mode.

[0017] Examples of the method implementation

[0018] Example 1

[0019] To carry out resuscitation work, the well was stopped and formation water + ML81B was injected through the annulus in a volume of 5 m 3 The well was started for 30 minutes. The well was shut down for 30 minutes. Then, the sucker rod string was raised to a height of 5 m, necessary to disengage the Type 6 insert-type sucker rod pump from the lower support. The upper support rose relative to the lower support, creating a concentric channel between the tubing string and the insert-type borehole pump. The formation fluid in the tubing string, under the influence of a high pressure differential, flowed through the formed channel and filter back into the well, washing away residual mechanical impurities and wellbore sediments and cleaning the well. Next, flushing was performed by pumping 40 m of formation water and ML81B into the tubing string. 3 .

[0020] After completing the direct flushing procedure, the insert-type well pump was reinstalled in the lower support, and the well was returned to operating mode.

[0021] Example 2

[0022] To carry out resuscitation work, the well was stopped and formation water + MS20MPS in a volume of 5 m3 was injected through the annulus. 3The well was started for 30 minutes. The well was shut down for 30 minutes. Then, the sucker rod string was raised to a height of 5 m, necessary to disengage the Type 6 insert-type sucker rod pump from the lower support. The upper support rose relative to the lower support, creating a concentric channel between the tubing string and the insert-type borehole pump. The formation fluid in the tubing string, under the influence of a high pressure differential, flowed through the formed channel and filter back into the well, washing away residual mechanical impurities and wellbore sediments and cleaning the well. Next, flushing was performed by pumping formation water and MS20MPS into the tubing string in a volume of 34 m3. 3 .

[0023] After completing the direct flushing procedure, the insert-type well pump was reinstalled into the lower support, and the well was returned to operating mode.

[0024] The method for washing the filter of a borehole pump will improve the efficiency of washing the filter of a borehole pump by uniformly distributing the cleaning agent inside and outside the filter, inside the pump, and allowing a waiting time sufficient for the cleaning agent to act on solid mechanical particles and hydrodynamic treatment.

Claims

A method for flushing a borehole pump filter, which includes lowering a rod pump of the insert type into the borehole, equipped with a filter at the intake, stopping the borehole after the filter becomes clogged with mechanical impurities and borehole deposits, raising the column of pump rods to a height sufficient to disengage the pump from the lower support and raise the upper support relative to it with the formation of a concentric channel between the pump and the tubing for the flow of formation fluid from the pipe column into the borehole, installing the pump in the lower support and returning the borehole to the operating mode, characterized in that after stopping the borehole after the filter becomes clogged, a cleaning agent is pumped into the annular space in a volume of more than 0 and up to 5 m 3, start the well for a time sufficient to fill the pump and filter with a cleaning agent and amounting to 15 minutes, stop the well for a time sufficient for the cleaning agent to act on solid mechanical particles on the filter and pump, amounting to 30 minutes, after raising the column of pump rods to a height sufficient to disengage the pump from the lower support and raise the upper support relative to it, equal to 5 m, pump the cleaning agent through the tubing in a volume equal to 2 volumes of the well tubing, install the pump in the lower support and return the well to the operating mode.

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