NL2009165C2

NL2009165C2 - System and method for production of a primary fluid, such as oil, from an underground reservoir.

Info

Publication number: NL2009165C2
Application number: NL2009165A
Authority: NL
Inventors: Bert Fennechienes Alberts
Original assignee: Steenmaat Beheer B V
Priority date: 2012-07-10
Filing date: 2012-07-10
Publication date: 2014-01-13
Also published as: CA2891195A1; EP2877675B1; WO2014011043A2; EP2877675A2; CA2891195C; WO2014011043A3; US20150191984A1

Abstract

The invention relates to a system and a method for production of a fluid from an underground reservoir. The system comprises a casing (10) with an internal tubing (11); a set of plug-in devices that are each arranged to perform a specific function; means for wire line installation and retrievement of the plug-in devices; means for (un) locking and means for sealing the plug-in devices in the casing. Two secondary fluid lines (15) alongside the tubing are connectable to the plug-in devices via inlets/outlets (12, 13) for operating the devices. The plug-in device can be a blind plug, gas lift valve, downhole pump, packer, check valve etc.

Description

SYSTEM AND METHOD FOR PRODUCTION OF A PRIMARY FLUID, SUCH AS OIL, FROM AN UNDERGROUND RESERVOIR

The present invention relates to a system and a method for production of a 5 primary fluid, such as oil, from an underground reservoir, comprising: A casing to be put into the ground for defining an internal elongate hollow tubing running in the direction of the reservoir;

At least one plug-in device to be received in the tubing, which plug-in device is provided with means for sealing the plug-in device in the tubing; 10 Means for wireline installation and retrievement of the plug-in device in the tubing;

Means for locking and unlocking the plug-in device in the tubing, wherein the casing comprises at least two secondary fluid lines running in longitudinal direction substantially parallel to the tubing, which secondary fluid lines 15 are connectable to the plug-in device for operating the plug-in device A system according to the preamble is known in the art and is described in the Dutch patent application NL8602658. The known system relates to a pumping device for pumping a fluid, especially oil, out of a well to the ground surface.

In the known system the plug-in device comprises a pump and a hydraulic 2 0 drive for the pump, wherein the drive is arranged at a position below the pump seen in the direction towards the underground reservoir.

The known system has many advantages. The main advantage lies in the use of wireline techniques to pull the pump out of the tubing and change it or repair it and install it afterwards into the tubing, to overcome malfunctions.

2 5 The need for expensive work over towers is successfully avoided and loss of production time can be kept to a minimum. Further advantages follow from the noiseless functioning and the environmentally friendly character of the known system.

The invention has for its object to further improve the known system.

30 The system according to the invention is characterized in that the system comprises a set of two or more plug-in devices, each comprising at least one functional section extending between adjacent sealing means, wherein the first functional section of a first plug-in device comprises a drive for a pump, wherein the pump is connectable to the drive such that the pump lies closer to the reservoir than 35 the first functional section in the position of use.

2

According to the invention the system provides a set of plug-in devices that are each arranged to perform a specific function. All plug-in devices can be standardized with respect to the dimensions and can be interchanged quickly using the wireline techniques known in the art. The most important function relates to the 5 pumping function and necessitates a drive, preferably a hydraulic drive. According to a further aspect of the invention the position of the pump and the drive within the plug-in device are reversed. This brings about the important possibility of using a flexible pump. The pump capacity largely depends on the dimensions of the pump, which can be adapted to the specific well conditions when using the system 10 according to the invention.

According to the first preferred embodiment the functional section of a second one of the plug-in devices comprises an internal passage for unobstructed flow of the primary fluid. In this first preferred embodiment the plug-in device is arranged as a blind plug allowing testing of the proper functioning of the well.

15 Furthermore this first preferred embodiment allows for water injection or steam injection, which are different techniques used in the field of oil production. Water injection wells can be found both on- and offshore to increase oil recovery from an existing reservoir. It is well known in the art to produce wells in a cyclic steam manner for a few cycles (also known as the huff and puff method) before being put 2 0 on the steam flooding regime with other wells.

According to a second preferred embodiment an open cage is connected to the second one of the plug-in devices for accommodating measurement devices, such as temperature, pressure or flow measurement devices. In this second preferred embodiment the plug-in device is arranged to function as an observation 2 5 plug allowing determination of the prevailing well conditions.

According to a third preferred embodiment the functional section of a third one of the plug-in devices is arranged for injection of a tertiary fluid into the reservoir through the secondary fluid lines, wherein the functional section comprises a number of flow out openings for the tertiary fluid. In this third preferred embodiment 3 0 the plug-in device allows for injection of gas for gas lifting of the oil out of the reservoir. This third preferred embodiment can also be used to inject chemical solvents to clean the well equipment underground thereby increasing production.

According to a further development of the third embodiment the flow out openings are provided with closure means that are pretensioned in the closed 35 position. The pretension force can be chosen carefully to provide a back pressure 3 and to make sure that there is no leakage of oil emulsion into the secondary fluid lines of the tubing.

According to a further preferred embodiment the drive is a hydraulic drive arranged to be driven by a hydraulic fluid to be fed through the secondary fluid lines.

5 Preferably the pump is a plunger or piston pump, a positive displacement pump or a centrifugal displacement pump.

The invention also relates to a plug-in device as described as part of the system according to the invention.

The invention further relates to a method of which the steps are described in 10 claim 9.

The invention will now further be described referring to the appending figures, in which:

Figure 1A shows a schematic view of a first embodiment of a system 15 according to the invention;

Figure 1B shows the system of figure 1A in cross section;

Figure 2 shows a first embodiment of a plug-in device as part of the system according to the invention;

Figure 3 shows a second embodiment of a plug-in device as part of the 2 0 system according to the invention;

Figure 4 shows a third embodiment of a plug-in device as part of the system according to the invention; and

Figure 5 shows a fourth embodiment of a plug-in device according to the invention.

25

In all figures equal reference numerals denote equal features.

Figure 1A shows a schematic view of a part of a system 1 for production of a primary fluid according to the present invention. Figure 1B shows system 1 in cross section.

30 System 1 is a Wireline Retrievable Oil Production (WROP) system. System 1 comprises a casing 10 that is to be put into the ground wherein an underground reservoir of primary fluid is present. Casing 10 normally has a tubular shape defining an internal elongate hollow tubing 11 that in the position of use runs in the direction of the reservoir (not shown).

35 Casing 10 comprises at least two lines 15 for secondary fluids that run in 4 longitudinal direction substantially parallel to the tubing 11. Each line has an inlet/outlet 12, 13.

In tubing 11a plug-in device 20 is received. Locking means lock the plug-in device 20 in place in tubing 11. Suitable locking means are available in the relevant 5 art and may comprise, for example, a landing nipple or a locking mandrel.

The plug-in device 20 is sealed in tubing 11 by suitable sealing means, such as packing 23. According to the invention system 1 comprises a set of two or more plug-in devices each providing a different technical function in relation to production of the primary fluid. In figures 2, 3, 4 and 5 four different embodiments are shown.

10 All of these embodiments are preferably at least in part standardized. In the preferred embodiments shown all plug-in devices comprise a part largely similar to the part shown in figure 2. Herein a functional section 24 is present that is arranged according to the function to be fulfilled by the plug-in device. In figure 2 a blind plug is shown. In figure 3 an observation blind plug is shown. In figure 4 a gas (or fluid) 15 injection plug is shown and in figure 5 a plug with hydraulic drive and pump is shown.

Each of the plug-in devices can be selected, installed and operated for an optimal production of the primary fluid, as will be described in more detail in the following.

2 0 Figure 2 shows a first embodiment of a plug-in device 20 according to the invention. Plug-in device 20 is a so-called blind plug that can be used to test a production well. Plug-in device 20 comprises a generally tubular body 21. Plug-in device 20 is provided with locking means formed by a locking mandrel 22. Suitable locking mandrels are available in the art. In the preferred embodiment shown four 2 5 seals 23 are present on the circumference of body 21. The functional section 24 extends between adjacent seals. In this embodiment body 21 comprises an internal passage for substantially unobstructed flow of the primary fluid. The blind plug 20 is useful for checking operational pressures in the secondary fluid lines 15.

Plug-in device 20 is a blind plug closing off the inlet/outlet 12, 13 of the 30 secondary fluid lines 15. Once the plug-in device 20 is locked in position by the locking means 22, the sealing means 23 and part of the body 21 seal off the inlet 12 and the outlet 13 of the secondary fluid lines 15 of the tubing 11 (see figure 1B). Blind plug 20 is also very useful for water injection, which is commonly used in oil production to increase pressure and thereby stimulate production. The oil is literally 35 swept or displaced from the reservoir and pushed towards the well bore.

5

As an alternative to water steam may be injected using the blind plug 20. Suitable materials and seals need than to be chosen that can withstand the higher temperatures.

Figure 3 shows a second embodiment of a plug-in device according to the 5 invention. Plug-in device 30 according to figure 3 has the part 20 shown in figure 2. Plug-in device 30 is shown in the position of use wherein an open cage 31 is connected to the body 21 for accommodating measurement devices, such as temperature, pressure or flow measurement devices (not shown). The cage construction 31 will protect the measurement devices during installation respectively 10 retrievement of the plug-in device in respectively out of the tubing. The blind plug 20 will protect the secondary fluid lines 15. Plug-in device 30 is very suitable to observe the flow, temperature and pressure in the well.

Figure 4 shows third embodiment of a plug-in device 40 according to the invention. Plug-in device 40 is a so-called gas lift plug. In the field of oil production 15 gas lift is commonly used when an oil well has insufficient reservoir pressure to produce oil. Injected gas aerates the fluid to reduce its density. The formation pressure is then to lift the oil column and force the fluid out of the well bore. The plug-in device 40 is arranged for injection of a suitable gas or fluid, called tertiary gas or fluid, through the secondary fluid lines 15. . Arrows G indicate the direction of 2 0 gas flow, while arrows O indicate the direction of flow of oil (emulsion) from the well.

Once the plug-in device 40 is locked in position by the locking means 22, the sealing means 23 surround the inlets 12 and 13 of the secondary fluid lines 15 of the tubing 11 (see figure 1B). Suitable openings (not shown) in plug-in device 40 allow for a gas flow G to enter the plug-in device 40 through the inlets.

2 5 The functional section 44 comprises a number of flow out openings 45 for the tertiary gas or fluid to mix with the oil emulsion. Preferably flow out openings 45 are closed off with valves 46 that are pretensioned in the closed position by means of springs 47

It is noted that plug-in device 40 can also be used to inject chemical solvents 3 0 to remove unwanted deposit from for example paraffin present in the tubing, lines and other underground production equipment. The parts of plug-in device 40 that come into contact with the chemicals to be injected need to be carefully chosen, but suitable materials are available in the relevant art.

Figure 5 shows a fourth embodiment of the plug-in device according to the 35 invention. Plug-in device 50 is shown schematically (left) and in cross section (right).

6

Plug-in device 50 comprises a first functional section 54 that is arranged as a drive 55 for a pump 57 that is present in a second functional section 56 connected to the first functional section. Plug-in device 50 is shown in the position of use. It is apparent that in the position of use the second functional section comprising the 5 pump lies closer to the reservoir than the first functional section 54.

Once the plug-in device 50 is locked in position by the locking means 22, the sealing means 23 surround the inlet 12 and the outlet 13 of the secondary fluid lines 15 of the tubing 11 (see figure 1B). Openings 24 in plug-in device 50 allow for a flow F of hydraulic fluid via the inlet 12 and the outlet 13 to cause rotation R of the drive 10 55.

In the inserts two types of suitable hydraulic drives are shown. Turbine motor 55-1 or positive displacement motor 55-2 are both available on the market and can be coupled to a suitable pump 57. The drive 55 is arranged to allow for upward passage of the primary fluid that is pumped out of the reservoir. In drives 55-1 and 15 55-2 a hollow central rod allows for passage of oil.

Examples of suitable pumps are a plunger or piston pump, a positive displacement pump or a centrifugal displacement pump. Preferably a piston pump is used in applications at lower pressure, for instance lower than 70 bars. In higher pressure applications ranging up to 2000 bar, plunger pumps are used. Both types 2 0 of pumps use a cylindrical mechanism to create a reciprocating motion along an axis thereby building up pressure inside to force fluid through the pump. The overall capacity of the piston pumps and plunger pumps can be calculated using the area of the piston or plunger, the stroke length, the number of pistons or plungers and the speed of the drive. The position of the pump below the hydraulic drive as seen in the 2 5 direction of the oil reservoir allows the dimensions of the pump to be flexibly adapted to the circumstances of the well.

It is noted that openings 24 are suitable for use in the plug-in device 40 to allow for a gas flow G to enter the plug-in device 40 via the inlets.

According to the invention a method is provided for production of a primary 30 fluid, such as oil, from an underground reservoir, using the system according to the invention. The method according to the invention comprises the following steps: a) Putting the casing into the ground for defining an internal elongate hollow tubing running in the direction of the reservoir; b) Selecting one of the plug-in devices to be received in the tubing; 35 c) Installing the plug-in device in the tubing using the wireline installation 7 means; d) Locking the plug-in device in the tubing; e) Operating the plug-in device by feeding secondary or tertiary fluid in the plug-in device; 5 f) Unlocking the plug-in device from the tubing; g) Retrieving the plug-in device out of the tubing using the wireline retrievement means; and h) Optionally repeating steps b) through g) for another one of the plug-in devices.

10

In the relevant technical field by wireline a cabling technology is meant used by operators of oil and gas wells to lower equipment into the well. In the context of the present invention a flexible cable is used to let the plug-in devices sink into the tubing and/or to pull it up out of the tubing. Several types of flexible cables known in 15 the art are suitable in the context of the present invention, including wireline, such as described in NL8602658, coiled tubing or flexible rod.

The invention is of course not limited to the described and shown preferred embodiments. All possible combinations of the embodiments are hereby disclosed and included expressly. The invention relates generally to any embodiment falling 2 0 within the scope of protection as defined in the claims and as seen in the light of the foregoing description and accompanying drawings.

Claims

A system for producing a primary fluid, such as oil, from an underground reservoir, comprising:

A system for producing a first fluid according to claim 1, wherein the functional section of a second insertion device comprises an internal passage 2. for unhindered flow of the primary fluid.

A system for producing a primary fluid according to claim 2, wherein an open cage is connected to the second insertion device for accommodating measuring devices, such as temperature, pressure or flow measuring devices.

4. System for producing a primary fluid according to claim 1, 2 or 3, wherein the functional section of a third insertion device is arranged for injection of a tertiary fluid into the reservoir through the secondary fluid lines, wherein the functional section has a number of outflow openings for the tertiary fluid.

A system for producing a primary fluid according to claim 4, wherein the outflow openings are provided with closing means which are prestressed in the closed position.

An enclosure to be provided in the ground for defining an internal elongated hollow tube that extends toward the reservoir; At least one plug-in device to be received in the tube and provided with means for sealing the plug-in device in the tube; Means for wireline installation and uninstallation of the insertion device in the tube; Means for locking and unlocking the insertion device in the tube, wherein the enclosure comprises at least two secondary fluid lines, which extend longitudinally substantially parallel to the tube, which secondary fluid lines can be connected to the insertion device for operating the insertion device, characterized in that the system comprises a set of two or more insertion devices, each comprising at least one functional section extending between adjacent sealing means, wherein the first functional section of a first insertion device comprises a drive for a pump wherein the pump is connectable to the drive such that the pump is closer to the reservoir than the first functional section in the position of use.

A system for producing a primary fluid according to one or more of the preceding claims, wherein the drive is a hydraulic drive adapted to be driven by a hydraulic fluid to be supplied through the secondary fluid lines.

A system for producing a primary fluid according to one or more of the preceding claims, wherein the pump is a plunger or piston pump, a positive displacement pump or a centrifugal displacement pump.

8. Plug-in device as described as part of the system according to one or more of the preceding claims.

Method for producing a primary fluid, such as oil, from an underground reservoir, using a system according to one or more of the preceding claims 1-7, comprising the steps of: 2. a) Applying the enclosure to the soil for defining an internal elongated hollow tube that extends in the direction of the reservoir; b) Selecting one of the insertion devices to be received in the tube; c) Installing the plug-in device into the tube using 2. the wireline installation means; d) Locking the insertion device in the tube; e) Operating the insertion device by supplying secondary or tertiary fluid to the insertion device; f) Unlocking the tube insertion device; G) Uninstalling the insertion device from the tube using the wireline uninstallation means; and h) Optionally repeating steps b) to g) for another insertion device. 35