CN116411862A - Stratum well cementation control system and method with narrow density window - Google Patents
Stratum well cementation control system and method with narrow density window Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 115
- 230000001105 regulatory effect Effects 0.000 claims abstract description 19
- 239000004568 cement Substances 0.000 claims description 56
- 238000005553 drilling Methods 0.000 claims description 44
- 239000012530 fluid Substances 0.000 claims description 41
- 239000002002 slurry Substances 0.000 claims description 38
- 230000015572 biosynthetic process Effects 0.000 claims description 36
- 241000220259 Raphanus Species 0.000 claims description 15
- 235000006140 Raphanus sativus var sativus Nutrition 0.000 claims description 15
- 238000010276 construction Methods 0.000 claims description 10
- 230000001502 supplementing effect Effects 0.000 claims description 9
- 230000001276 controlling effect Effects 0.000 claims description 7
- 238000002347 injection Methods 0.000 claims description 6
- 239000007924 injection Substances 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 238000001125 extrusion Methods 0.000 claims description 4
- 238000004886 process control Methods 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 2
- 230000005484 gravity Effects 0.000 claims description 2
- 239000007790 solid phase Substances 0.000 claims description 2
- 238000005755 formation reaction Methods 0.000 description 24
- 238000011010 flushing procedure Methods 0.000 description 9
- 238000006073 displacement reaction Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 6
- 239000007788 liquid Substances 0.000 description 6
- 230000004580 weight loss Effects 0.000 description 6
- 238000004590 computer program Methods 0.000 description 5
- 125000006850 spacer group Chemical group 0.000 description 5
- 238000002955 isolation Methods 0.000 description 4
- 238000005192 partition Methods 0.000 description 4
- 238000004080 punching Methods 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 230000002706 hydrostatic effect Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
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- 230000003068 static effect Effects 0.000 description 3
- 230000002147 killing effect Effects 0.000 description 2
- 230000000670 limiting effect Effects 0.000 description 2
- 239000003208 petroleum Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000003129 oil well Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/13—Methods or devices for cementing, for plugging holes, crevices or the like
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/06—Arrangements for treating drilling fluids outside the borehole
- E21B21/063—Arrangements for treating drilling fluids outside the borehole by separating components
- E21B21/065—Separating solids from drilling fluids
- E21B21/066—Separating solids from drilling fluids with further treatment of the solids, e.g. for disposal
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/04—Casing heads; Suspending casings or tubings in well heads
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/06—Blow-out preventers, i.e. apparatus closing around a drill pipe, e.g. annular blow-out preventers
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Abstract
The invention provides a narrow-density window stratum well cementation control system, which comprises: the automatic controller generates a pressure regulating instruction when overflow or leakage occurs in the cementing process of well cementation; the throttling manifold is connected with the automatic controller, executes a pressure regulation instruction and ensures that the bottom hole pressure in the well cementation and cementing process is within the stratum pressure range of the narrow density window; the pressure compensating pump is connected with the throttling manifold through a three-way connecting piece, and back pressure is applied according to a wellhead back pressure value in the waiting process, so that the bottom hole pressure in the waiting process is ensured to be in the stratum pressure range of the narrow density window. The invention applies the closed-loop idea to the whole well cementation process, and the well cementation cementing and waiting-setting process has the advantages of effectively ensuring the bottom hole pressure in the narrow-density window stratum pressure range, realizing the safe quality guarantee and well cementation of the narrow-density window stratum, along with simple operation and strong practicability, and is suitable for on-site popularization and application.
Description
Technical Field
The invention relates to the technical field of oil-gas field well cementation engineering, in particular to a narrow-density window stratum well cementation control system and method.
Background
With the rapid increase of national economy, the demand of China for petroleum is increasing, the exploitation of petroleum is gradually changed to deeper and more complex blocks, the geological condition of oil and gas reservoirs is also more and more complex, and the problem of narrow density window in the well drilling and completion process is still a worldwide problem. Because of the narrow pressure window of the drilled stratum and the uncertainty of the stratum, various complex conditions such as blowout, leakage, collapse, clamping and the like are easy to occur in the drilling process, and once the complex conditions are improperly treated, safety accidents such as blowout and the like are extremely easy to occur. The design and construction of well cementation are greatly influenced by the narrow density window encountered by well drilling, and the well cementation is a hidden project with short duration and high cost due to the long open hole section and the large pressure system in the well cementation process, and once the problem is solved, the well cementation fluid is difficult to remedy, so the design and control of the well cementation fluid in the formation of the narrow density window in the well cementation process are important.
Aiming at a stratum with a narrow density window, the conventional well cementation mode in the prior art has the problem that both pressure stability and leakage prevention are difficult to consider in the well cementation process. Currently, a common method for drilling narrow density window formations is to perform controlled pressure drilling. The control pressure drilling adopts a closed loop system, and the bottom hole pressure is always in a safe density window by accurately controlling the annular pressure profile. Although the drilling process can be controlled, the narrow density window problem in the cementing process is not a good solution to the prior art.
Aiming at the problems in the prior art, the invention provides a narrow-density window stratum well cementation control system and a method.
Disclosure of Invention
In order to solve the difficult problem of cementing operation of a narrow-density window stratum in the prior art, the invention provides a narrow-density window stratum cementing control system, which is characterized by comprising the following components:
the automatic controller is used for generating a pressure regulating instruction when overflow or leakage occurs in the well cementation process;
the choke manifold is connected with the automatic controller and is used for executing the pressure regulating instruction so as to ensure that the bottom hole pressure is in the formation pressure range of the narrow density window in the well cementation and cementing process;
and the pressure supplementing pump is connected with the throttling manifold through a three-way connecting piece and is used for applying back pressure according to a wellhead back pressure value in the waiting process so as to ensure that the bottom hole pressure in the waiting process is in the formation pressure range of a narrow density window.
According to one embodiment of the invention, the system comprises:
a vibrating screen connected to the choke manifold for filtering the solid phase in the slurry;
the circulating tank is connected with the vibrating screen and used for storing drilling fluid so as to meet the circulating requirement;
the drilling pump is connected with the circulating tank and is used for providing necessary energy for the circulation of drilling fluid, and the drilling fluid is conveyed into the drilling tool at a certain pressure and flow rate to complete the whole circulation process;
the cement head is connected with the drilling pump and is used for injecting cement paste and releasing a special tool of a rubber plug, and is arranged at the top end of the sleeve when cementing well and cementing cement;
the well cementation pump is connected with the cement head and is used for providing power for well cementation construction operation;
a water tank connected to the well cementation pump;
the blowout preventer is connected with the cement head, belongs to a well control device, and is used for preventing blowout from happening and ensuring construction safety;
the casing head is connected with the blowout preventer through a four-way connecting piece and is used for supporting the gravity of the technical casing and the oil layer casing;
a casing is coupled to the casing head to provide a passageway for flow from the producing zone to the surface.
According to one embodiment of the invention, when the radish head is installed on the well cementation site, the annular space is sealed through the radish head, and three ends of the three-way connecting piece are respectively connected with the choke manifold, the pressure compensating pump and the casing head.
According to one embodiment of the invention, when the radish head is not installed at the cementing site, a rotary control head is installed above the blowout preventer, thereby sealing off the annulus.
According to one embodiment of the invention, the system comprises:
the first flat valve is connected between the pressure supplementing pump and the three-way connecting piece;
and a second flapper valve connected between the choke manifold and the three-way connection.
According to one embodiment of the invention, the system comprises:
and the cement slurry density determining device is used for determining the cement slurry density in the well cementation and cementing process according to the real drilling pressure window in the well drilling process.
According to one embodiment of the invention, the system comprises:
and the waiting and condensing process control device is used for calculating the wellhead back pressure value in the waiting and condensing process and generating a pressure compensating instruction according to the wellhead back pressure value so as to control the pressure compensating pump to apply back pressure.
According to another aspect of the present invention there is also provided a narrow density window formation cementing control method, performed by a system as defined in any one of the preceding claims, the method comprising:
when overflow occurs in the cementing process, generating a pressure regulating instruction through the automatic controller;
executing the pressure regulating instruction through the choke manifold to ensure that the bottom hole pressure is in the formation pressure range of a narrow density window in the well cementation and cementing process;
when leakage occurs in the cementing process of well cementation, generating a pressure regulating instruction through the automatic controller, reducing the discharge capacity or increasing the opening of the throttle valve, and gradually reducing the wellhead back pressure to 0; if the leakage is larger than the critical value, the wellhead back-extrusion cement operation is needed after the cement injection is finished;
and applying back pressure according to a wellhead back pressure value through the pressure compensating pump in the waiting process so as to ensure that the bottom hole pressure in the waiting process is in the formation pressure range of a narrow density window.
According to one embodiment of the invention, the method comprises:
and calculating to obtain the wellhead back pressure value in the waiting and solidifying process, and generating a pressure compensating instruction according to the wellhead back pressure value so as to control the pressure compensating pump to apply back pressure.
According to another aspect of the invention there is also provided a storage medium containing a series of instructions for performing the method steps as described above.
Compared with conventional well cementation, the system and the method for controlling the well cementation of the narrow-density window stratum, provided by the invention, apply the closed-loop idea to the whole well cementation process, and design and accurate control of parameters such as density, displacement, back pressure and the like are purposefully carried out through the narrow-density window stratum, so that the bottom hole pressure in the well cementation and waiting and solidifying processes can be effectively ensured to be within the pressure range of the narrow-density window stratum, the safe quality-keeping well cementation of the narrow-density window stratum is realized, and the system and the method have the characteristics of simplicity in operation and strong practicability, and are suitable for on-site popularization and application.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention, without limitation to the invention. In the drawings:
FIG. 1 shows a block diagram of a narrow density window formation cementing control system in accordance with one embodiment of the present invention;
FIG. 2 shows a block diagram of a cementing site with a radish head according to one embodiment of the present invention; and
fig. 3 shows a block diagram of the construction of a cementing site without a radish head installed in accordance with one embodiment of the present invention.
The labels in the figures are as follows: 1. a water tank; 2. a well pump; 3. a drilling pump; 4. blowout preventer; 5. a four-way connecting piece; 6. a casing head; 7. a first flat valve; 8. a second flapper valve; 9. a pressure compensating pump; 10. a choke manifold; 11. an automatic controller; 12. a vibrating screen; 13. a circulation tank; 14. a cement head; 15. drill pipe (casing); 16. a formation; 17. an annulus; 18. rotating the control head; 19. and a three-way connecting piece.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following embodiments of the present invention will be described in further detail with reference to the accompanying drawings.
FIG. 1 shows a block diagram of a narrow density window formation cementing control system in accordance with one embodiment of the present invention.
As shown in fig. 1, a narrow density window formation cementing control system 100 comprises an automatic controller 11, a choke manifold 10, and a pressure make-up pump 9.
Specifically, the automatic controller 11 is used for generating a pressure regulating instruction when overflow or leakage occurs in the cementing process of well cementation; the throttle manifold 10 is connected with the automatic controller 11 and is used for executing a pressure regulation instruction so as to ensure that the bottom hole pressure is in the formation pressure range of a narrow density window in the well cementation and cementing process; the pressure supplementing pump 9 is connected with the choke manifold 10 through a three-way connecting piece 19 and is used for applying back pressure according to a wellhead back pressure value in the waiting process so as to ensure that the bottom hole pressure in the waiting process is in the formation pressure range of a narrow density window.
In one embodiment, a narrow density window formation cementing control system 100 includes a cement slurry density determination device for determining a cement slurry density during a cementing process from a real bit pressure window during drilling.
Specifically, the cement slurry density determination device needs to collect formation pore pressure p through geological logging data and adjacent well data p Collapse pressure p b Formation fracture pressure p f Respectively calculating the equivalent density of the corresponding stratum pore pressure, namely the equivalent density rho p Equivalent density of collapse pressure ρ b The equivalent density of the fracture pressure of the stratum is ρ f 。
The cement paste density determining device needs to calculate friction pressure drop p in the well cementation process L ：
Wherein ρ is Drilling machine For density of drilling fluid, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the f is friction coefficient; v is the annulus return speed, m/s; h is well depth, m; d is the annular outside diameterM; d is the inner diameter of the annulus and m;
the cement paste density determining device needs to determine the cement paste density according to a real drilling pressure window in the drilling process, specifically:
if p f -Max(p p ,p b )＞p L +Δp, cement slurry density is designed according to conventional well cementing designs.
If p f -Max(p p ,p b )＜p L +Δp, a certain safety pressure coefficient Δp cannot be added according to the conventional design, Δp is calculated from the safety added value of drilling fluid density (0.05-0.1 g/cm3 of an oil well and 0.07-0.15 g/cm3 of a gas well), Δp= 0.00981gh, and various fluids exist in an annulus in the well cementation process: flushing fluid, spacer fluid, cement slurry, plug fluid and the like, and annular static equivalent density ρ in the well cementation process ESD Taking:
ρ ESD ＝Max(ρ p ,ρ b )
the cement paste density calculation meets the following requirements:
ρ ESD gh＝ρ drilling machine gh 1 +ρ Punching machine gh 2 +ρ Partition board gh 3 +ρ Collar collar gh 4 +ρ Tail of tail gh 5
Wherein ρ is Drilling machine For density of drilling fluid, g/cm 3 ；ρ Punching machine Density of rinse solution, g/cm 3 ；ρ Partition board To isolate the density of the liquid, g/cm 3 ；ρ Collar collar Is the density, g/cm of the collar slurry of the cement slurry 3 ；ρ Tail of tail G/cm, the density of the cement slurry tail stock 3 ；ρ ESD Is the static equivalent density of annular space in the well cementation process, g/cm 3 The method comprises the steps of carrying out a first treatment on the surface of the h is the well depth, m; h is a 1 The length of the annular drilling fluid after well cementation is m; h is a 2 The length of the annulus flushing fluid after well cementation is m; h is a 3 The length of the annulus spacer fluid after well cementation is m; h is a 4 The length m of the annular cement slurry collar after well cementation is finished; h is a 5 And m is the tail slurry length of the annular cement slurry after well cementation is finished.
Further, for the involved rinse and spacer fluid density and length requirements, the specification needs to be met:
(1) The density of the flushing liquid is generally 1.0-1.03g/cm 3 ；
(2) The isolation liquid density is generally smaller than the cement paste density by 0.06-0.12g/cm 3 ；
(3) The lengths of the flushing fluid and the isolation fluid in the annulus are not more than 250m when the flushing fluid or the isolation fluid is used alone; when the two-dimensional optical fiber is used together, the design dosage is carried out according to the length of 2:1, and the total length is not more than 300m; the well depth is more than 3000m, and the total consumption of the isolating liquid and the flushing liquid is increased by 0.2-0.3m when 300m is added 3 ；
Further, for the cement slurry collar and tail slurry density and length requirements involved, the specification requirements need to be met:
(1) Returning the slurry to the designed elevation;
(2) And returning the tail slurry to the main sealed well section for more than 50-150 m.
(3) The density of the collar slurry is 0.01-0.02g/cm lower than that of the tail slurry 3 。
According to the cement paste density calculated by the cement paste density determining device, circulating according to the system shown in the figure 1, the figure 2 or the figure 3, if leakage occurs in the cementing process, adopting a multi-time grouting method or performing wellhead reinjection, thereby reducing annulus pressure and reducing leakage amount; if overflow occurs in the cementing process, the pressure of the choke manifold 10 is regulated by the automatic controller 11, the regulation of the choke manifold 10 is required to meet the condition that the vertical pressure value is constant in a low pump speed test, and the back pressure value at the moment is the required back pressure value, so that the influence of overflow on the cementing quality is reduced.
In one embodiment, a narrow density window formation cementing control system 100 comprises a leakage control device for generating a pressure adjustment command through an automatic controller when leakage occurs in the cementing process, reducing the displacement or increasing the opening of a throttle valve, and gradually reducing the wellhead back pressure to 0, thereby reducing the annulus pressure and the leakage amount; if the leakage is larger than the critical value, the wellhead back-extrusion cement operation is needed after the cement injection is finished.
The overflow control device calculates the bottom hole pressure p in the cementing process according to the selected density of various fluids in the annulus d ：
p d ＝ρ Drilling machine gh 1i +ρ Punching machine gh 2i +ρ Partition board gh 3i +ρ Collar collar gh 4i +ρ Tail of tail gh 5i +∑p fi +p a
Wherein h is 1i The length m of the annular drilling fluid in the cementing process; h is a 2i The length m of annulus flushing fluid in the cementing process; h is a 3i The length m of the annular isolation liquid in the cementing process; h is a 4i The slurry collar length m of the annular cement slurry in the cement injection process; h is a 5i The length m of the annular cement slurry tail slurry in the cement injection process; p is p d Is the bottom hole pressure and Mpa in the cementing process; p is p fi Is the friction pressure drop of each slurry column in the cementing process, and Mpa; v is the annulus flow rate, m/s; d is the annular outer diameter, m; d is the inner diameter of the annulus and m; p is p a Is wellhead back pressure and MPa.
The casing pressure in the cementing process is as 0 as possible, the operation without pressure is carried out, the bottom hole pressure meets the formation pressure range of a narrow density window, and the method comprises the following steps:
Max(p p ,p b )＜p d ＜p f
if the bottom hole pressure is not in the stratum pressure range with a narrow density window, the cement slurry density is increased or reduced or the displacement is regulated according to the actual situation until the requirement is met.
In the process of stopping the pump, the bottom hole pressure consists of hydrostatic column pressure and wellhead back pressure:
p' d ＝ρ drilling machine gh 1i +ρ Punching machine gh 2i +ρ Partition board gh 3i +ρ Collar collar gh 4i +ρ Tail of tail gh 5i +p a
Because friction disappears, a certain back pressure is needed to be added at the moment to keep the bottom hole pressure constant, and at the moment, p is a ＝∑p fi 。
In one embodiment, a narrow density window formation cementing control system 100 includes a waiting process control device for calculating a wellhead back pressure value in a waiting process and generating a back pressure command according to the wellhead back pressure value to control a back pressure applied by a back pressure pump.
In the waiting and solidifying process, because cement paste is hydrated, annulus pressure can be reduced, and well kick can possibly occur, wellhead back pressure needs to be applied in the waiting and solidifying process, and wellhead back pressure value p a Calculated from the following formula:
wherein τ is static gel strength, pa; z is the depth of the cement paste and m.
Specifically, the waiting process control device applies the back pressure by the pressure supplementing pump 9 in accordance with the calculated back pressure value based on the back pressure value calculated by the above formula.
The invention is based on the basic principle of pressure control well drilling, uses the closed-loop idea in the well cementation process, and achieves the aim of safely preserving the well cementation by designing the related parameters of the density, the displacement and the like of the well cementation fluid and matching with an automatic choke manifold to adjust the opening of a choke valve so as to control the bottom hole pressure in a stratum pore-fracture pressure window (a stratum pressure range with a narrow density window). The method is simple to operate, high in practicability and suitable for well cementation construction of stratums with narrow density windows.
Fig. 2 shows a block diagram of the construction of a cementing site with a radish head according to one embodiment of the present invention.
As shown in fig. 2, when the radish head is installed on the well cementation site, the annular space is sealed by the radish head, and three ends of the three-way connecting piece 19 are respectively connected with the choke manifold 10, the pressure compensating pump 9 and the casing head 6. The first flat valve 7 is connected between the pressure compensating pump 9 and the three-way connection 19, and the second flat valve 8 is connected between the choke manifold 10 and the three-way connection 19.
The system connection flow shown in fig. 2 is as follows: connecting a well fixing pump 2, a drilling pump 3 and a choke manifold 10; the choke manifold 10 is connected to the casing head 6 using a high pressure hose and the second flapper valve 8 is opened. The pressure supplementing pump 9 is connected to a throttle manifold 10; the pressure compensating pump 9 is connected to the throttle manifold 10 through a high-pressure rubber pipe, and the first flat valve 7 is closed. And determining the annular equivalent density ECD of the narrow-density window, and calculating the required density of the well cementing slurry. After the cementing is finished, the first flat valve 7 is opened, the second flat valve 8 is closed, and the choke manifold 10 can be cleaned or removed. Wherein, ECD, namely equivalent circulating density, refers to the density converted by the sum of hydrostatic column pressure and circulating friction in the circulating process, namely: the bottom hole pressure during the cycle is converted to density in terms of well depth, ecd=pd/(gh).
Before cementing, the connection with the well killing manifold of the well team is firstly disconnected, and a connection mode shown in figure 2 is established. If the radish head is installed on site, the radish head can seal the annular space to form a closed loop system, so the first circulation flow shown in fig. 2 is as follows: connecting the cementing pump 2 and the water tank 1 to the cementing head 14, and pumping cementing fluid (flushing fluid, spacer fluid, cement slurry, cementing fluid, etc.) into the drill pipe (sleeve) 15 through the cementing pump 2; the conventional drilling pump 3 is connected with the circulation tank 13 and then connected with the cement head 14, displacement fluid is pumped into a drill rod (sleeve) 15 by the drilling pump 3, fluid in an annulus 17 enters the choke manifold 10 through the sleeve head 6, and then returns to the circulation tank 13 through the vibrating screen 12. In order to reduce the influence of cement slurry weight loss during the waiting period, a replenishing pump 9 is additionally arranged in front of a throttle manifold 10 and is used for replenishing the annular space during the waiting period.
As shown in fig. 2, after the casing head 6 is connected with the four-way connecting piece 5, the casing head is connected with an automatic controller 11, and the back pressure is regulated by regulating the opening degree of a choke manifold 10, so that the bottom hole pressure is controlled within the formation pressure range of a narrow density window; the three-way connecting piece 19 is connected between the choke manifold 10 and the casing head 6, and the replenishing pump 9 is connected with the three-way connecting piece 19 and is used for replenishing pressure loss caused by cement slurry weight loss in the well cementation and setting process.
Fig. 3 shows a block diagram of the construction of a cementing site without a radish head installed in accordance with one embodiment of the present invention.
As shown in fig. 3, when the wellhead is not installed at the cementing site, a rotary control head 18 is installed above the blowout preventer 14, thereby sealing off the annulus. The first flat valve 7 is connected between the pressure compensating pump 9 and the three-way connection 19, and the second flat valve 8 is connected between the choke manifold 10 and the three-way connection 19.
The system connection flow shown in fig. 3 is as follows: connecting a well fixing pump 2, a drilling pump 3 and a choke manifold 10; the choke manifold 10 is connected to the rotary control head 18 using a high pressure hose, opening the second flapper valve 8. The pressure supplementing pump 9 is connected to a throttle manifold 10; the pressure compensating pump 9 is connected to the throttle manifold 10 through a high-pressure rubber pipe, and the first flat valve 7 is closed. And determining the annular equivalent density ECD of the narrow-density window, and calculating the required density of the well cementing slurry. After the cementing is finished, the first flat valve 7 is opened, the second flat valve 8 is closed, and the choke manifold 10 can be cleaned or removed. Wherein, ECD, namely equivalent circulating density, refers to the density converted by the sum of hydrostatic column pressure and circulating friction in the circulating process, namely: the bottom hole pressure during the cycle is converted to density in terms of well depth, ecd=pd/(gh).
Before cementing, the connection with the well killing manifold of the well team is firstly disconnected, and a connection mode shown in figure 3 is established. If there is no radish head in the field, a rotary control head (RCD) 18 may be installed above blowout preventer 4 so that the excluder ring void forms a closed loop system, and so the second cycle flow (FIG. 3) is: connecting the cementing pump 2 and the water tank 1 to the cementing head 14, and pumping cementing fluid (flushing fluid, spacer fluid, cement slurry, cementing fluid, etc.) into the drill pipe (sleeve) 15 through the cementing pump 2; the conventional drilling pump 3 is connected with the circulation tank 13 and then connected with the cement head 14, displacement fluid is pumped into a drill rod (sleeve) 15 by the drilling pump 3, fluid in an annulus 17 enters the choke manifold 10 through a rotary control head (RCD) 18, and then returns to the circulation tank 13 through the vibrating screen 12. In order to reduce the influence of cement slurry weight loss during the waiting period, a replenishing pump 9 is additionally arranged in front of a throttle manifold 10 and is used for replenishing the annular space during the waiting period.
As shown in fig. 3, a rotary control head (RCD) 18 is mounted above the wellhead blowout preventer stack 14 for closing the annulus to form a closed loop system; the choke manifold 10 is connected with a rotary control head (RCD) 18 and then connected with an automatic controller 11, and back pressure is regulated by regulating the opening degree of the choke manifold 10, so that the bottom hole pressure is controlled within the formation pressure range of a narrow density window; a three-way connecting piece 19 is connected between the choke manifold 10 and a rotary control head (RCD) 18, and the replenishing pump 9 is connected with the three-way connecting piece 19 and is used for replenishing pressure loss caused by cement slurry weight loss in the well cementation process.
The invention discloses a narrow-density window stratum well cementation control system. The system comprises a soft part and a hard part, and the bottom hole pressure is controlled within the formation pressure range of a narrow density window through the combination of the soft part and the hard part. Optimizing design of related parameters such as the density, the discharge capacity, the back pressure and the like of the well cementation fluid with a narrow density window, ensuring that the back pressure is not applied as much as possible in the grouting process, and reducing the possibility of leakage; applying back pressure according to a design value in the process of stopping the pump, and maintaining the bottom hole pressure constant; in the waiting and setting process, back pressure is applied according to the pressure change rule in the cement slurry weight loss process, so that the pressure loss in the weight loss process is compensated; when burst leakage occurs, adopting a multiple grouting method or performing wellhead reinjection; when the overflow is sudden, the back pressure is applied through the automatic choke manifold, so that the influence of the overflow on the well cementation quality is reduced.
The invention combines the advantages of a hardware system (automatic throttle manifold) for adjusting back pressure according to the needs by the detailed soft design of the density, the displacement, the back pressure and the like of the well cementation fluid, controls the bottom hole pressure in the well cementation process such as cementing, waiting and the like within a safe density window, has the characteristics of simple operation, strong practicability and easy popularization, and is suitable for the formation well cementation construction of a narrow density window.
The invention also provides a control method for the well cementation of the stratum with a narrow density window, which is implemented by a system shown in fig. 1 or fig. 2 or fig. 3, in particular:
s1, when overflow occurs in the cementing process, generating a pressure adjusting instruction through an automatic controller.
And S2, executing a pressure regulation instruction through a choke manifold to ensure that the bottom hole pressure in the well cementation and cementing process is within the stratum pressure range of the narrow density window.
S3, when leakage occurs in the cementing process of well cementation, generating a pressure regulating instruction through the automatic controller, reducing the discharge capacity or increasing the opening of the throttle valve, and gradually reducing the wellhead back pressure to 0; if the leakage is larger than the critical value, the wellhead back-extrusion cement operation is needed after the cement injection is finished.
And S4, applying back pressure according to a wellhead back pressure value through a pressure supplementing pump in the waiting process so as to ensure that the bottom hole pressure in the waiting process is in the formation pressure range of the narrow density window.
In one embodiment, a wellhead back pressure value in the waiting and solidifying process is calculated, and a pressure compensating instruction is generated according to the wellhead back pressure value so as to control the pressure compensating pump to apply back pressure.
The system and the method for controlling the well cementation of the stratum with the narrow-density window can be matched with a computer-readable storage medium, the storage medium is stored with a computer program, and the computer program is executed to operate the method for controlling the well cementation of the stratum with the narrow-density window. The computer program is capable of executing computer instructions, which include computer program code, which may be in source code form, object code form, executable file or some intermediate form, etc.
The computer readable storage medium may include: any entity or device capable of carrying computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer Memory, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth.
It should be noted that the content of the computer readable storage medium may be appropriately increased or decreased according to the requirements of the jurisdiction's legislation and the patent practice, for example, in some jurisdictions, the computer readable storage medium does not include an electrical carrier signal and a telecommunication signal according to the legislation and the patent practice.
In conclusion, compared with conventional well cementation, the system and the method for controlling the well cementation of the stratum with the narrow density window, provided by the invention, apply the closed-loop idea to the whole well cementation process, and design and accurate control of parameters such as density, discharge capacity, back pressure and the like are purposefully carried out through the stratum with the narrow density window, so that the bottom hole pressure in the well cementation and waiting and solidifying processes can be effectively ensured to be within the pressure range of the stratum with the narrow density window, the safe quality preservation well cementation of the stratum with the narrow density window is realized, and the system and the method have the characteristics of simplicity in operation and strong practicability and are suitable for field popularization and application.
It is to be understood that the disclosed embodiments are not limited to the specific structures, process steps, or materials disclosed herein, but are intended to extend to equivalents of these features as would be understood by one of ordinary skill in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.
In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front," "rear," "head," "tail," and the like are used as an orientation or positional relationship based on that shown in the drawings, merely to facilitate description of the invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "connected," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.
The embodiments of the invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
Although the embodiments of the present invention are disclosed above, the embodiments are only used for the convenience of understanding the present invention, and are not intended to limit the present invention. Any person skilled in the art can make any modification and variation in form and detail without departing from the spirit and scope of the present disclosure, but the scope of the present disclosure is still subject to the scope of the appended claims.
Claims (10)
1. A narrow density window formation cementing control system, the system comprising:
the automatic controller is used for generating a pressure regulating instruction when overflow or leakage occurs in the well cementation process;
the choke manifold is connected with the automatic controller and is used for executing the pressure regulating instruction so as to ensure that the bottom hole pressure is in the formation pressure range of the narrow density window in the well cementation and cementing process;
and the pressure supplementing pump is connected with the throttling manifold through a three-way connecting piece and is used for applying back pressure according to a wellhead back pressure value in the waiting process so as to ensure that the bottom hole pressure in the waiting process is in the formation pressure range of a narrow density window.
2. A narrow density window formation cementing control system according to claim 1, wherein said system comprises:
a vibrating screen connected to the choke manifold for filtering the solid phase in the slurry;
the circulating tank is connected with the vibrating screen and used for storing drilling fluid so as to meet the circulating requirement;
the drilling pump is connected with the circulating tank and is used for providing necessary energy for the circulation of drilling fluid, and the drilling fluid is conveyed into the drilling tool at a certain pressure and flow rate to complete the whole circulation process;
the cement head is connected with the drilling pump and is used for injecting cement paste and releasing a special tool of a rubber plug, and is arranged at the top end of the sleeve when cementing well and cementing cement;
the well cementation pump is connected with the cement head and is used for providing power for well cementation construction operation;
a water tank connected to the well cementation pump;
the blowout preventer is connected with the cement head, belongs to a well control device, and is used for preventing blowout from happening and ensuring construction safety;
the casing head is connected with the blowout preventer through a four-way connecting piece and is used for supporting the gravity of the technical casing and the oil layer casing;
a casing is coupled to the casing head to provide a passageway for flow from the producing zone to the surface.
3. The narrow-density window stratum well cementation control system of claim 2, wherein when a radish head is installed on a well cementation site, annular space is sealed through the radish head, and three ends of the three-way connecting piece are respectively connected with the choke manifold, the pressure compensating pump and the casing head.
4. The narrow density window formation cementing control system of claim 2, wherein a rotary control head is installed above said blowout preventer to seal the annulus when no radish head is installed at the cementing site.
5. A narrow density window formation cementing control system according to claim 1, wherein said system comprises:
the first flat valve is connected between the pressure supplementing pump and the three-way connecting piece;
and a second flapper valve connected between the choke manifold and the three-way connection.
6. A narrow density window formation cementing control system according to claim 1, wherein said system comprises:
and the cement slurry density determining device is used for determining the cement slurry density in the well cementation and cementing process according to the real drilling pressure window in the well drilling process.
7. A narrow density window formation cementing control system according to claim 1, wherein said system comprises:
and the waiting and condensing process control device is used for calculating the wellhead back pressure value in the waiting and condensing process and generating a pressure compensating instruction according to the wellhead back pressure value so as to control the pressure compensating pump to apply back pressure.
8. A method of controlling narrow density window formation cementing performed by the system of any one of claims 1-7, the method comprising:
when overflow occurs in the cementing process, generating a pressure regulating instruction through the automatic controller;
executing the pressure regulating instruction through the choke manifold to ensure that the bottom hole pressure is in the formation pressure range of a narrow density window in the well cementation and cementing process;
when leakage occurs in the cementing process of well cementation, generating a pressure regulating instruction through the automatic controller, reducing the discharge capacity or increasing the opening of the throttle valve, and gradually reducing the wellhead back pressure to 0; if the leakage is larger than the critical value, the wellhead back-extrusion cement operation is needed after the cement injection is finished;
and applying back pressure according to a wellhead back pressure value through the pressure compensating pump in the waiting process so as to ensure that the bottom hole pressure in the waiting process is in the formation pressure range of a narrow density window.
9. A method of controlling the cementing of a narrow density window formation according to claim 8, comprising:
and calculating to obtain the wellhead back pressure value in the waiting and solidifying process, and generating a pressure compensating instruction according to the wellhead back pressure value so as to control the pressure compensating pump to apply back pressure.
10. A storage medium containing a series of instructions for performing the method steps of any one of claims 8-9.
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| CN202111639744.4A CN116411862A (en) | 2021-12-29 | 2021-12-29 | Stratum well cementation control system and method with narrow density window |
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| CN202111639744.4A CN116411862A (en) | 2021-12-29 | 2021-12-29 | Stratum well cementation control system and method with narrow density window |
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