CN115982537A - Positioning method and releasing method after pipe cleaner jamming - Google Patents
Positioning method and releasing method after pipe cleaner jamming Download PDFInfo
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- CN115982537A CN115982537A CN202211565975.XA CN202211565975A CN115982537A CN 115982537 A CN115982537 A CN 115982537A CN 202211565975 A CN202211565975 A CN 202211565975A CN 115982537 A CN115982537 A CN 115982537A
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Abstract
The invention discloses a positioning method of a pipe cleaner after blocking, which comprises the steps of calculating the density of oil, gas and water, the average pressure of a path of a submarine pipeline cleaned by the pipe cleaner, the average temperature in the submarine pipeline, the actual volume of the oil, gas and water in the submarine pipeline, the nominal flow of the pipe cleaner in a vertical pipe section and the flow rate of the pipe cleaner in a horizontal pipe section according to various physical parameters of the oil, gas and water conveyed in the submarine pipeline, and then calculating the position of the pipe cleaner in the submarine pipeline according to the time when the pipe cleaner enters the submarine pipeline and the movement speed of the pipe cleaner in the submarine pipeline. The invention also discloses a releasing method after the blockage of the pipe cleaner. The pipe cleaner can more accurately position the blocking position of the pipe cleaner in the submarine pipeline, can release the pipe cleaner after blocking when the pipe cleaner cleans insoluble salt deposited on the inner wall of the submarine pipeline, and has better releasing effect and lower cost.
Description
Technical Field
The invention relates to the technical field of submarine pipeline cleaning, in particular to a positioning method and a blockage releasing method after blockage of a pipe cleaner.
Background
The offshore platform conveys the mined material to an FPSO (floating production storage and drainage device) through a submarine pipeline, the inlet end of the submarine pipeline is connected with the offshore platform, and the outlet end of the submarine pipeline is connected with the FPSO. Most of submarine pipelines are oil-gas-water multiphase mixed transportation, three-phase fluid often contains media such as carbon dioxide, hydrogen sulfide, salts such as chloride, stratum-transported gravel and wax, and the submarine pipelines need to be cleaned regularly, such as every month, so that the pipeline transportation efficiency is improved. Sea waterThe dynamic balance of the production water scale in the bottom pipe is:
because the fluid in the submarine pipeline is influenced by factors such as internal friction, friction resistance along the pipeline wall, interaction between turbulent flow and laminar flow, heat exchange with seawater and the like, the pressure and the temperature of the submarine pipeline are continuously reduced from the inlet end to the outlet end, oil, gas and water are gradually layered, the partial pressure of carbon dioxide is reduced, the dissolution balance of the fluid is broken, and precipitates such as calcium carbonate, magnesium carbonate and barium sulfate are continuously separated out, so that the fluid in the submarine pipeline is continuously separated out along the flowing direction, a hard calcium carbonate scale layer is in fan-shaped distribution on the cross section of the submarine pipeline, the scale is more serious when the hard calcium carbonate layer is closer to the outlet end of the submarine pipeline, the mixed conveying efficiency of the submarine pipeline is continuously reduced, electrochemical corrosion and bacterial corrosion are aggravated, the wall thickness of the submarine pipeline is reduced, local corrosion perforation or corrosion failure is caused, and the internal corrosion condition of the submarine pipeline is directly influenced.
Therefore, the pipeline cleaner is required to be used for cleaning pipelines which are easy to scale in the submarine pipelines and the like, the pipeline cleaner in the conventional cleaning operation of the offshore device mainly comprises a scraper ball and a high/low-density foam ball, the interference design is adopted, so that scale blocks in the mixed-conveying submarine pipeline are continuously stripped and accumulated at the front end of the pipeline cleaner, along with the gradual increase of accumulated scale blocks, the resistance of the pipeline cleaner is increased, the crushing pressure of the scraper ball is far higher than the high set point of the shut-down pressure of the mixed-conveying submarine pipeline production operation, the phenomenon of pipe cleaner blocking is caused, the production of an upstream ocean platform is shut down, the produced oil gas cannot be conveyed, the production operation of a downstream floating production oil storage and drainage device can also be disturbed by the fluctuation of working conditions, the 'blocking ball' position point of the pipeline cleaner is quickly judged after blocking, and then an emergency blocking-releasing scheme can be effectively formulated in a targeted manner, so that the loss of the oil gas yield can be effectively reduced.
The blockage relieving method for the pipe cleaner of the high-wax-content submarine mixed transportation pipeline comprises the following steps: s1, determining the blocking position of a pipe cleaner; s2, putting a continuous pipeline into the tail end of the sea pipe to a blocking section, and establishing a medium circulation channel; s3, driving out residual liquid in the section of the sea pipe; s4, injecting a cleaning reagent into the tail end of the sea pipe through a pressing device, and S5, standing and soaking for 5 hours after the cleaning reagent is added; s6, injecting gas lift liquid, detecting the saturation of the cleaning reagent, and judging the dissolved wax amount; s7, additionally arranging a burstable blind plate, and continuously discharging residual liquid in the marine pipe; and S8, pressurizing at the inlet end of the submarine pipeline to push out the pipe cleaner meeting the clamping.
However, in the above scheme, the error of the position of the pipe encountering card calculated by only considering the empirical formula of the operation time of the pipe cleaning ball, the flow rate of the pipeline and the volume of the pipeline is large, and the position of the pipe cleaning device encountering card is not accurate enough, so that the dosage of the injected cleaning agent and other reagents is not accurate enough. Meanwhile, the scheme only considers the blockage of the accumulated wax in the submarine mixed transportation pipeline to the submarine mixed transportation pipeline, and does not consider the blockage of the sediment of slightly soluble or insoluble salt such as calcium carbonate, magnesium carbonate, barium sulfate and the like to the submarine pipeline.
Disclosure of Invention
The invention aims to overcome the defects that the blocking position of a pipe cleaner is not accurately positioned and the blockage of a submarine pipeline caused by insoluble salt precipitation is not considered in the prior art, and provides a positioning method and a blockage releasing method after the pipe cleaner is blocked. The positioning method after the pipe cleaner is blocked can more accurately position the blocking position of the pipe cleaner in the submarine pipeline. According to the releasing method after blockage of the pipe cleaner, provided by the invention, when the pipe cleaner cleans insoluble salt deposited on the inner wall of the submarine pipeline, the pipe cleaner can be released after blockage, the releasing effect is better, and the cost is lower.
The purpose of the invention can be achieved by adopting the following technical scheme:
a positioning method for blocked pipe cleaner comprises the following steps:
s1.1: according to various physical parameters of oil, gas and water conveyed in a submarine pipeline in the production process, the density rho of the oil, gas and water is calculated, and the calculation formula is as follows:
G t ＝ρ o +ρ ng R p +ρ w V w
V t at pressure p and temperature T, with 1m per production 3 Total volume of oil-gas-water mixture of ground degassed crude oil, unit m 3 /m 3 ；
B o The volume factor of the crude oil in m 3 /m 3 ；
Z is gas compression factor, dimensionless;
p st absolute Standard pressure, 1.01325X 10 5 Pa；
T st -standard temperature, 293.15K;
R p production gas-to-oil ratio, m 3 /m 3 ；
R s Dissolved gas-oil ratio, m 3 /m 3 ；
V w -production water to oil ratio,%;
ρ o density of produced surface degassed crude oil, kg/m 3 ；
ρ ng Density of produced natural gas, kg/m 3 ；
ρ w Density of produced water, kg/m 3 ；
G t -with 1m per production 3 Total mass of oil, gas and water of ground degassed crude oil in kg/m 3 ；
Rho-average value of density of oil, gas and water mixture in a certain pressure range and temperature range, kg/m 3 ；
S1.2: by calculating the average pressure drop in the subsea conduit
Calculating the end pressure P of the path of the subsea pipeline cleaned by the pig 2 To calculate the cleaning of the pigMean pressure of the path of the passing subsea pipeline->
The specific process is as follows:
g-acceleration of gravity, 9.80665m/s 2 ；
Lambda is the drag coefficient of the oil-gas-water mixture in the vertical pipe section, and is dimensionless;
d-the inner diameter of the submarine pipeline, mm;
P 1 -the pressure at the starting point of the subsea pipeline cleaned by the pig, MPa;
P 2 -the end point pressure, MPa, of the subsea pipeline cleaned by the pig;
Q o -daily oil production, m 3 /d；
S1.3: according to the temperature T of the inlet end of the submarine pipeline 1 And the temperature T of the outlet end 2 Calculating average temperature in subsea pipelines
T 1 -the temperature at the inlet end of the subsea pipeline in K;
T 2 -the temperature at the outlet end of the subsea pipeline in units K;
s1.4: according to the mean pressure in the submarine pipeline
And the mean temperature->
Calculating the actual volume of oil, gas and water in the submarine pipeline>
Thereby calculating the nominal flow Q in the vertical pipe section in the submarine pipeline Is perpendicular to ：
S1.5: using nominal flow Q of pig in vertical pipe section Is perpendicular to Calculating the flow velocity v of the pipe cleaner in the vertical pipe section Is perpendicular to ：
D Is perpendicular to -vertical sea pipe section outer diameter, mm;
Δθ is perpendicular to -vertical marine pipe section wall thickness, mm;
s1.6: according to the tip pressure P 2 And pressure P at the outlet end of the subsea pipeline O Calculating the mean pressure
As average pressure of horizontal pipe sections in a subsea pipeline:
P o -pressure at the outlet end of the subsea pipe conduit, MPa;
here take P O Can be read in a detection instrument in a floating production oil storage and drainage device by utilizing P o And P 2 The calculated average pressure value is taken as the average pressure in the horizontal pipe section.
S1.7: according to the average pressure of horizontal pipe sections in submarine pipelines
And average temperature in a subsea pipeline>
Calculating the actual volume of oil, gas and water in a horizontal pipe section in the submarine pipeline>
Thereby calculating the nominal flow Q in the horizontal section of the subsea pipeline Level of ：
S1.8: using nominal flow Q in horizontal sections in a subsea pipeline Is perpendicular to Calculating the flow velocity v of the pig in the horizontal section Level of ：
D Level of -outside diameter of the horizontal marine pipe section, mm;
Δθ level of -horizontal marine pipe section wall thickness, mm;
s1.9: calculating the position of the pig in the subsea pipeline based on the time the pig enters the subsea pipeline and the speed of movement of the pig in the subsea pipeline:
t card with a detachable cover -the time until the pig enters the sea pipe until seizure occurs;
t 1 the time from when the pig enters the sea pipe to when it leaves the vertical pipe section;
in the offshore platform mining operation, a submarine pipeline conveys a mined substance from an offshore platform to a floating production oil storage and drainage device, and at the moment, the substance conveyed in the submarine pipeline is generally an oil-gas-water mixture. When the pipe cleaner is used for cleaning the submarine pipeline, the pipe cleaner enters the submarine pipeline from the inlet end of the submarine pipeline, namely the end of the submarine pipeline connected with an ocean platform, the pipe cleaner needs to be pressurized from the inlet end of the submarine pipeline after entering the submarine pipeline so as to push the pipe cleaner to advance in the submarine pipeline, and the pressurization is usually realized through the oil-gas-water mixture conveyed in the submarine pipeline pumped in, so that the phenomenon that new substances are injected into the submarine pipeline can be avoided, the cleaning operation is completed but the residual substances in the submarine pipeline are difficult to discharge, meanwhile, the used oil-gas-water mixture can be obtained locally, and the original pump for conveying the oil-gas-water mixture and related devices are used, so that the operation is more convenient.
The oil, gas and water mixture is pumped from the inlet end of the submarine pipeline, and the oil, water and gas production of each oil well, the pressure and temperature data at the inlet end of the submarine pipeline on the ocean platform, the pressure and temperature at the outlet end of the submarine pipeline on the floating production oil storage and drainage device and the like can be used for carrying out relevant data acquisition in the process of mining operation. The positioning method comprehensively considers a plurality of factors, more accurately calculates the specific blocking position of the pipe cleaner in the submarine pipeline, and provides guidance for subsequent blockage removal operation.
The submarine pipeline from an ocean platform to the floating production oil storage and drainage device comprises two vertical pipe sections and a horizontal pipe section located between the two vertical pipe sections, wherein the two vertical pipe sections are respectively a first vertical pipe section and a second vertical pipe section, the submarine pipeline extends from the ocean platform to a seabed and is the first vertical pipe section, then horizontally extends to the lower part of the floating production oil storage and drainage device on the seabed and is the horizontal pipe section, finally extends to the floating production oil storage and drainage device from the seabed and is the second vertical pipe section, the first vertical pipe section and the second vertical pipe section both droop downwards, the vertical pipe section and the horizontal pipe section are connected through expansion bending, the vertical pipe section is not necessarily completely perpendicular to the horizontal plane under the influence of various factors such as sea waves in sea water, and the vertical pipe section is approximate to a vertical state for convenience of expression and understanding. After the pipe cleaner enters the inlet end of the submarine pipeline, the pipe cleaner is used as a boundary, the submarine pipeline through which the pipe cleaner passes is the submarine pipeline at the rear end of the pipe cleaner, and the submarine strand pipeline through which the pipe cleaner does not pass is the submarine pipeline at the front end of the pipe cleaner. Because the fluid in the submarine pipeline gradually has scale to separate out along the flow direction, the interference magnitude of different degrees exists in different positions of the submarine pipeline by the pipe cleaner, oil, gas, water and medium and the like at the rear end of the pipe cleaner are regarded as uniformly distributed and pushed, and the inner wall of the submarine pipe does not have residual scale after the pipe cleaner is transported and scraped, so that the moving speed of the pipe cleaner is calculated in sections.
The first vertical pipe section closer to the ocean platform is a vertical pipe section and is close to the pump, so that the fluid flow speed is high, the sediments are small, and the pipe cleaner can not be blocked at the section basically. And the second vertical pipe section is positioned at the downstream, and the sediment is basically and completely precipitated in the horizontal pipe section, so the sediment cannot be precipitated in the second vertical pipe section, and meanwhile, the sediment is difficult to be precipitated on the inner side wall of the second vertical pipe section due to the vertical placement of the second vertical pipe section. Thus, the pig will generally jam only in the horizontal section and only in extreme cases will there be some chance of jamming in the vertical section, but the likelihood is minimal and jamming in the vertical section is not generally a result of deposits. In summary, the calculation process provided in the present scheme mainly aims at the blockage of the pipe cleaner in the horizontal pipe section, and the vertical pipe section in steps S1.1 to S1.9 is the first vertical pipe section.
A method for releasing blockage of a pipe cleaner comprises the following steps:
s1: positioning a pig using the positioning method after pig jamming as claimed in claim 1;
s2: after the position of a pipe cleaner is determined, the coiled tubing is stretched into the submarine pipeline until an outlet of the coiled tubing reaches the position where a scale block is peeled off at the front end of the pipe cleaner, meanwhile, the required amount of the foaming agent is calculated according to the volume of liquid in the submarine pipeline at the front end of the pipe cleaner, and the required amount of the scale dissolving agent is calculated according to the volume of the submarine pipeline at the front end of the pipe cleaner;
s3: injecting a certain amount of foaming agent into the submarine pipeline through the coiled tubing for foaming, and pumping nitrogen into the submarine pipeline through the coiled tubing to empty the foam;
s4: preparing a scale dissolving agent solution according to the calculated scale dissolving agent dosage, injecting the prepared scale dissolving agent solution into the submarine pipeline through the continuous oil pipe, and reacting for a certain time;
s5: starting a pressurizing pump to pressurize the submarine pipeline at the rear end of the pipe cleaner, if the pressure is normal, releasing the blockage successfully, continuing to operate the pipe cleaner, if the pressure of the submarine pipeline at the front end of the pipe cleaner continues to rise to the highest point in the pressurizing process, releasing the blockage unsuccessfully, and repeating the steps S3 and S4;
s6: and (5) after the blockage is successfully released in the step (S5), the pipe cleaner continues to operate, if the pipe cleaner is blocked again, the steps (S1) to (S5) are repeated until the pipe cleaner reaches the tail end of the submarine pipeline to finish the pipe cleaning operation of all the positions of the submarine pipeline.
According to the positioning method after the pipe cleaner is blocked, the position of the pipe cleaner can be more accurately positioned, the actual using amount can be more accurate when the pipe cleaner is blocked, the problem that the using amount is insufficient and the reagent needs to be repeatedly used for multiple times can be avoided, the operation time and the cost are increased, and the waste and the damage to the inner wall of the submarine pipeline caused by excessive using amount can be avoided.
The unfreezing method comprises the steps of firstly, using a foaming agent to be matched with nitrogen to evacuate liquid in a submarine pipeline at the front end of a pipe cleaner; then, injecting a proper amount of scale dissolving agent solution into the liquid-emptied submarine pipeline and waiting for the scale dissolving agent solution to react for a period of time, so that the deposit blocked by the pipe cleaner at the front end of the pipe cleaner reacts with the scale dissolving agent solution to be dissolved; and starting a pressurizing pump on the ocean platform to pressurize towards the inlet end of the submarine pipeline, namely pressurizing towards the rear end of the pipe cleaner, if the pressure is not increased, indicating that the pipe cleaner can move forwards, releasing the blockage successfully, if the pressure is increased all the time and is increased to the highest point of the pressure which can be borne by the submarine pipeline, stopping pressurizing to avoid damaging the submarine pipeline, judging that the pipe cleaner is still blocked and fails to release the blockage, and repeating the steps of discharging liquid and dissolving the scales to release the blockage again.
The method for positioning the blocked pipe cleaner can calculate the blocked position of the pipe cleaner in the submarine pipeline more accurately, so that the dosage of reagents such as a foaming agent, a scale dissolving agent and the like required can be controlled more accurately, waste caused by excessive foaming agent and scale dissolving agent and corrosion of the inner wall of the submarine pipeline caused by excessive scale dissolving agent can be avoided, meanwhile, the phenomenon that the scale dissolving agent is diluted due to incomplete liquid discharge caused by insufficient dosage of the foaming agent can be avoided, and blockage release failure caused by insufficient dosage of the scale dissolving agent can be avoided.
The scale dissolver is required to be prepared into a scale dissolver solution with a certain concentration and then can be injected into the submarine pipeline through the coiled tubing. The amount of the foaming agent is determined according to the volume of liquid in the submarine pipeline at the front end of the pipe cleaner, when blockage occurs for the first time, the volume of the liquid in the submarine pipeline at the front end of the pipe cleaner is the volume from the front end of the pipe cleaner to the outlet end of the submarine pipeline in the submarine pipeline, if scale dissolving fails for the first time in step S5, the liquid in the submarine pipeline at the front end of the pipe cleaner is the volume of the scale dissolving agent solution injected at the moment, and the amount of the foaming agent used is calculated according to the volume of the scale dissolving agent solution at the moment.
Further, the following steps are also included between steps S3 and S4:
s31: calculating the using amount of a cleaning agent and preparing a cleaning agent solution according to the volume from the front end of a pipe cleaner in the submarine pipeline to the outlet end of the submarine pipeline, and injecting the prepared cleaning agent solution into the submarine pipeline through a coiled tubing for pre-cleaning;
s32: and (4) calculating a required foaming agent according to the using amount of the cleaning agent solution in the step S31, injecting the foaming agent into the submarine pipeline through the coiled tubing for foaming, pumping nitrogen into the submarine pipeline through the coiled tubing to empty the foam, and then performing the step S4.
The steps S31 and S32 are cleaning operations, in order to allow the scale dissolving agent to react with the sediment sufficiently, the sediment and the oil stains attached to the surface of the submarine pipeline are cleaned with the cleaning agent before the scale dissolving agent is used after the liquid in the submarine pipeline at the front end of the pipe cleaner is emptied, and the cleaning agent solution after use is emptied with the foaming agent and nitrogen gas so as to perform subsequent scale dissolving operations. When the pipe cleaner is blocked for the first time, the scale dissolving agent is used for thoroughly cleaning oil stains on the submarine pipeline at the front end of the pipe cleaner, so that after blockage is released, the pipe cleaner can not be cleaned any more if being blocked again. If the submarine pipeline at the front end of the pipe cleaner is not completely cleaned in the first cleaning operation, only the deposits falling off from the front end of the pipe cleaner are cleaned, and the pipe cleaner needs to be cleaned again when blocked again.
Further, in the step S2, the submarine pipeline includes a first vertical pipe section with a top end inlet connected to the ocean platform, a first vertical pipe section with a top end outlet connected to the floating production oil storage and drainage device, and a horizontal pipe section arranged between the first vertical pipe section and the second vertical pipe section;
if the pipe cleaner is blocked in the horizontal pipe section, the volume of the prepared scale dissolving agent solution is the volume from the front end of the pipe cleaner in the horizontal pipe section to the joint between the horizontal pipe section and the second vertical pipe section; and if the pipe cleaner is blocked in the second vertical pipe section, the volume of the prepared scale dissolving agent solution is not more than the volume from the front end of the pipe cleaner in the second vertical pipe section to the outlet at the top end of the second vertical pipe section.
The method mainly aims at the blockage of the pipeline cleaner caused by the sediment, generally, the sediment scraped by the pipeline cleaner is accumulated in front of the pipeline cleaner to block the movement of the pipeline cleaner, and the sediment on the inner side wall of the submarine pipeline is more possibly to cause difficult scraping. When the pipe cleaner blocks in the horizontal pipe section, the deposit of the blocking pipe cleaner at the front end of the pipe cleaner can be fully immersed in the scale dissolving agent only by filling the scale dissolving agent in the horizontal pipe section at the front end of the pipe cleaner and enabling the liquid level of the scale dissolving agent in the vertical pipe section of the second to be higher than that of the pipe cleaner, the vertical pipe section of the second does not need to be fully immersed in the scale dissolving agent, the scale dissolving agent is saved, and the corrosion of the scale dissolving agent to a submarine pipeline is reduced. When the pig blocks in the second vertical pipe section, the dosage of the scale dissolver only needs to submerge the fallen deposits.
Further, in the step S3, an outlet at the top end of the second vertical pipe section is communicated with a sump oil chamber in the floating production, storage and drainage device, and foams in the submarine pipeline at the front end of the pipe cleaner are discharged into the sump oil chamber after being filled with nitrogen.
After the foaming agent is injected, the liquid at the front end of the pipe cleaner in the submarine pipeline is foamed, the foam is discharged out of the submarine pipeline after the nitrogen is injected, and the discharged foam is collected by utilizing a sump oil tank originally arranged in the floating production, storage and drainage device.
Further, in the step S3, a sampling position is arranged on a connecting pipeline between the outlet at the top end of the second vertical pipe section and the sump oil tank, and it can be determined that the foam is discharged when no foam is continuously sampled in the sampling position.
Further, in the step S3, a sampling position is arranged on a connecting pipeline between the outlet at the top end of the second vertical pipe section and the sump oil tank, and it can be determined that the foam is discharged when no foam is continuously sampled in the sampling position.
The sampling position can be provided with a ball valve, the ball valve is opened periodically, and the situation that the foam is emptied is judged after no continuous foam is observed.
Further, the foaming agent includes cocoyl propyl hydroxysulfobetaine 15% -25% (mass fraction), dodecyl imidazoline 5% -10% (mass fraction), alkyl polyether ammonium oxide 3% -15% (mass fraction), organic solution 1% -3% (mass fraction), inorganic salt solution 0.5% to 1% (mass fraction), and the rest is water; the amount of foaming agent is 100-500mg/L, depending on the volume of liquid in the subsea pipeline at the front end of the pig.
The organic solution is one or more of ethanol, isopropanol, ethylene glycol or triethanolamine. The inorganic salt solution is one or more of sodium formate, sodium silicate, sodium sulfate, sodium metasilicate pentahydrate or disodium phosphate.
Further, the scale dissolver solution comprises 10% (mass fraction) of HCl and 5% (mass fraction) of HF +2% of corrosion inhibitor, and the balance is water.
Further, the water used in the preparation of the scale dissolver solution can be replaced by seawater and other qualities.
Further, the cleaning agent is a multifunctional cleaning agent BH-QXJ-01.
The foaming agent, the scale dissolver and the cleaning agent can also be other commercially available finished products, and only need to be diluted and used according to the instructions of the finished product medicament.
Compared with the prior art, the invention has the beneficial effects that:
(1) The blocking position of the pipe cleaner in the submarine pipeline can be calculated more accurately, so that the blockage releasing operation can be guided better.
(2) During the unfreezing, thereby use the foaming agent to carry out the bubble with the liquid of dredging pipe ware front end in the submarine pipeline and empty liquid more thoroughly, avoid diluting the scale dissolvent, then, thereby use the scale dissolvent to dissolve the deposit and contact the jam that the deposit removed the dredging pipe ware. Meanwhile, the blocking position of the pipe cleaner on the submarine pipeline is accurately calculated, so that the dosage of the scale dissolver and the diluent can be more accurately calculated.
(3) Before the scale dissolver is used, the cleaning agent is used to remove oil stains attached to the surface of the sediment, so that the scale dissolver and the sediment can fully react.
Drawings
FIG. 1 is a schematic view of the connection structure of the ocean platform and the floating production oil storage and drainage device through a submarine pipeline;
FIG. 2 is a schematic view of the scale dissolver solution injection in example 3.
The graphic symbols are as follows:
1-an ocean platform, 2-a floating production oil storage and drainage device, 3-a submarine pipeline, 31-a first vertical pipe section, 32-a horizontal pipe section, 33-a second vertical pipe section, 4-a pipe cleaner, 5-sediment, 6-a coiled tubing and 7-a scale dissolver solution level.
Detailed Description
The present invention will be further described with reference to the following embodiments. Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; for a better explanation of the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms may be understood by those skilled in the art according to specific circumstances.
Example 1
A method for positioning a pipe cleaner 4 after jamming comprises the following steps:
s1.1: according to various physical parameters of oil, gas and water conveyed in a submarine pipeline in the production process, the density rho of the oil, gas and water is calculated, and the calculation formula is as follows:
G t ＝ρ o +ρ ng R p +ρ w V w
V t at pressure p and temperature T, with 1m per production 3 Total volume of oil-gas-water mixture of ground degassed crude oil in m 3 /m 3 ；
B o The volume factor of the crude oil in m 3 /m 3 ；
Z is gas compression factor, dimensionless;
p st absolute Standard pressure, 1.01325X 10 5 Pa；
T st -standard temperature, 293.15K;
R p production gas-to-oil ratio, m 3 /m 3 ；
R s Dissolved gas-oil ratio, m 3 /m 3 ；
V w -production water to oil ratio,%;
ρ o density of produced surface degassed crude oil, kg/m 3 ；
ρ ng Density of produced natural gas, kg/m 3 ；
ρ w Density of produced water, kg/m 3 ；
G t With 1m per production 3 Total mass of oil, gas and water of ground degassed crude oil in kg/m 3 ；
Rho-average value of density of oil, gas and water mixture in a certain pressure range and temperature range, kg/m 3 ；
S1.2: by calculating the average pressure drop in the subsea conduit
Calculating the end pressure P of the path of the subsea pipeline cleaned by the pig 2 Whereby the mean pressure of the path of the subsea pipeline cleaned by the pig is calculated ≥>
The specific process is as follows:
g-acceleration of gravity, 9.80665m/s 2 ；
Lambda is the drag coefficient of the oil-gas-water mixture in the vertical pipe section, and is dimensionless;
d-the inner diameter of the submarine pipeline, mm;
P 1 the sea floor cleaned by the pigThe pipeline starting point pressure is MPa;
P 2 -the end point pressure, MPa, of the subsea pipeline cleaned by the pig;
Q 0 -daily oil production, m 3 /d；
S1.3: according to the temperature T of the inlet end of the submarine pipeline 1 And the temperature T of the outlet end 2 Calculating average temperature in subsea pipelines
T 1 -the temperature at the inlet end of the subsea pipeline in K;
T 2 -the temperature at the outlet end of the subsea pipeline in units K;
s1.4: according to the mean pressure in the submarine pipeline
And the mean temperature->
Calculating the actual volume of oil, gas and water in the submarine pipeline>
Thereby calculating the nominal flow Q in the vertical pipe section in the submarine pipeline Is perpendicular to ：
S1.5: using nominal flow Q of pig in vertical pipe section Is perpendicular to Calculating the flow velocity v of the pipe cleaner in the vertical pipe section Is perpendicular to ：
D Is perpendicular to -vertical sea pipe section outer diameter, mm;
Δθ is perpendicular to -vertical marine pipe section wall thickness, mm;
s1.6: according to the tip pressure P 2 And pressure P at the outlet end of the subsea pipe conduit o Calculating the mean pressure
As average pressure of a horizontal section of a subsea pipeline:
P O -pressure at the outlet end of the subsea pipe conduit, MPa;
here take P O Can be read in a detection instrument in a floating production oil storage and drainage device by utilizing P O And P 2 The calculated average pressure value is taken as the average pressure in the horizontal pipe section.
S1.7: according to the average pressure of horizontal pipe sections in submarine pipelines
And an average temperature in the subsea pipeline>
Calculating the actual volume of oil, gas and water in a horizontal pipe section in the submarine pipeline>
Thereby calculating the nominal flow Q in the horizontal section of the subsea pipeline Level of ：
S1.8: using nominal flow Q in a horizontal section of a subsea pipeline Is perpendicular to Calculating the flow velocity v of the pipe cleaner in the horizontal pipe section Level of ：
D Level of -horizontal marine pipe section outer diameter, mm;
Δθ level of -horizontal sea pipe section wall thickness, mm;
s1.9: calculating the position of the pig in the subsea pipeline based on the time the pig enters the subsea pipeline and the speed of movement of the pig in the subsea pipeline:
t card with a detachable cover -the time until the pig enters the sea pipe until seizure occurs;
t 1 the pig enters the sea pipe to leaveThe time of opening the vertical pipe section;
during the exploitation operation of the ocean platform 1, the submarine pipeline 3 transports the exploited substance from the ocean platform 1 to the floating production oil storage and drainage device 2, and at the moment, the substance transported in the submarine pipeline 3 is generally an oil-gas-water mixture. When the pipe cleaner 4 is used for cleaning the submarine pipeline 3, the pipe cleaner 4 enters the submarine pipeline 3 from the inlet end of the submarine pipeline 3, namely one end of the submarine pipeline 3 connected with the ocean platform 1, the pipe cleaner 4 needs to be pressurized from the inlet end of the submarine pipeline 3 after entering the submarine pipeline 3 so as to push the pipe cleaner 4 to advance in the submarine pipeline 3, and the pressurization is usually realized through the oil-gas-water mixture conveyed in the submarine pipeline 3 by pumping, so that the situation that new substances are injected into the submarine pipeline 3 can be avoided, the cleaning operation is completed but the residual substances in the submarine pipeline 3 are difficult to discharge, meanwhile, the used oil-gas-water mixture can be obtained on the spot, the original pump and related devices for conveying the oil-gas-water mixture are used, and the operation is more convenient.
The oil, gas and water mixture is pumped from the inlet end of the submarine pipeline 3, the oil, water and gas production of each oil well, the pressure and temperature data of the inlet end of the submarine pipeline 3 at the ocean platform 1, the pressure and temperature data of the outlet end of the submarine pipeline 3 at the floating production oil storage and drainage device 2 and the like can be used for carrying out relevant data acquisition in the process of mining operation. The volume of the oil-gas-water mixture can be influenced by parameters such as temperature and pressure, and the volume of the oil-gas-water mixture can be changed by the oil-gas-water mixture in different proportions.
The submarine pipeline 3 comprises two vertical pipe sections and a horizontal pipe section 32 positioned between the two vertical pipe sections from the ocean platform 1 to the floating production oil storage and drainage device 2, wherein the two vertical pipe sections are respectively a first vertical pipe section 31 and a second vertical pipe section 33, the submarine pipeline 3 extends from the ocean platform 1 to the seabed to form the first vertical pipe section 31, then horizontally extends to the position below the floating production oil storage and drainage device 2 on the seabed to form the horizontal pipe section 32, finally extends to the floating production oil storage and drainage device 2 from the seabed to form the second vertical pipe section 33, the first vertical pipe section 31 and the second vertical pipe section 33 both droop downwards, the vertical pipe sections are connected with the horizontal pipe section 32 through expansion bends, the vertical pipe sections are not necessarily completely perpendicular to the horizontal plane under the influence of various factors such as sea waves in sea water, and the vertical pipe sections are approximate to be in a vertical state for convenience of expression and understanding. After the pipe cleaner 4 enters the inlet end of the submarine pipeline 3, the submarine pipeline 3 through which the pipe cleaner 4 passes is the submarine pipeline 3 at the rear end of the pipe cleaner 4, and the submarine strand pipeline through which the pipe cleaner 4 does not pass is the submarine pipeline 3 at the front end of the pipe cleaner 4. Because the fluid in the submarine pipeline gradually has scale to separate out along the flow direction, the interference magnitude of different degrees exists in different positions of the submarine pipeline 3 by the pipe cleaner 4, oil, gas, water and medium and the like at the rear end of the pipe cleaner 4 are regarded as uniformly distributed pushing, and the inner wall of the submarine pipeline has no scale after the pipe cleaner 4 is transported and scraped, so that the moving speed of the pipe cleaner 4 is calculated in sections.
The first vertical pipe section 31 closer to the ocean platform 1, because this section is a vertical pipe section and close to the pump, the fluid flow speed is fast, the sediment 5 is small, and the cleaning pig 4 basically cannot be blocked at this section. The second vertical pipe section 33 is located at the downstream, and the sediment is basically and completely precipitated in the horizontal pipe section, so the sediment 5 is not deposited in the second vertical pipe section 33, and meanwhile, the sediment 5 is difficult to deposit on the inner side wall of the second vertical pipe section 33 because the second vertical pipe section 33 is vertically placed. Thus, the cleaning pig 4 will generally only jam in the horizontal pipe section 32, and only in extreme cases will there be some chance of jamming in the vertical pipe section, but with minimal likelihood, and jamming in the vertical pipe section is not generally caused by the deposits 5. In summary, the calculation process provided in this embodiment mainly aims at the blockage of the pipe cleaner in the horizontal pipe section 32, and the vertical pipe section in steps S1.1 to S1.9 is the first vertical pipe section 31.
Example 2
As shown in fig. 1 and 2, a method for releasing the stuck pipe cleaner 4 comprises the following steps:
s1: positioning the cleaning pig 4 by using the positioning method after the blockage of the cleaning pig 4 according to claim 1;
s2: after the position of the pipe cleaner 4 is determined, the coiled tubing 6 is inserted into the submarine pipeline 3 until the outlet of the coiled tubing 6 reaches the scale stripping block at the front end of the pipe cleaner 4, meanwhile, the required amount of the foaming agent is calculated according to the volume of liquid in the submarine pipeline 3 at the front end of the pipe cleaner 4, and the required amount of the scale dissolving agent is calculated according to the volume of the submarine pipeline 3 at the front end of the pipe cleaner 4;
s3: injecting a certain amount of foaming agent into the submarine pipeline 3 through the coiled tubing 6 for foaming, and pumping nitrogen into the submarine pipeline 3 through the coiled tubing 6 to empty the foam;
s4: preparing a scale dissolving agent solution according to the calculated amount of the scale dissolving agent, injecting the prepared scale dissolving agent solution into the submarine pipeline 3 through the continuous oil pipe 6, and reacting for a certain time;
s5: starting a pressurizing pump to pressurize the submarine pipeline 3 at the rear end of the pipe cleaner 4, if the pressure is normal, releasing the blockage successfully, continuing to operate the pipe cleaner 4, if the pressure of the submarine pipeline 3 at the front end of the pipe cleaner 4 still continues to rise to the highest point in the pressurizing process, failing to release the blockage, and repeating the steps S3 and S4;
s6: and (5) after the blockage is successfully released in the step (S5), the pipe cleaner 4 continues to operate, if the pipe cleaner 4 is blocked again, the steps (S1) to (S5) are repeated until the pipe cleaner 4 reaches the tail end of the submarine pipeline 3 to finish the pipe cleaning operation of all the positions of the submarine pipeline 3.
According to the positioning method after the pipe cleaner 4 is blocked, the position of the pipe cleaner 4 can be positioned more accurately, the actual using amount can be more accurate when the pipe cleaner is unblocked, the problem that the reagent needs to be used repeatedly for multiple times due to insufficient using amount can be avoided, the operation time and the operation cost are increased, and the phenomenon that the inner wall of the submarine pipeline 3 is wasted and damaged due to excessive using amount can be avoided.
The unfreezing method comprises the steps of firstly, using a foaming agent to cooperate with nitrogen to evacuate liquid in the submarine pipeline 3 at the front end of a pipe cleaner 4; then, injecting a proper amount of scale dissolving agent solution into the liquid-emptied submarine pipeline 3 and waiting for the scale dissolving agent solution to react for a period of time, so that the deposit 5 which blocks the movement of the pipe cleaner 4 at the front end of the pipe cleaner 4 reacts with the scale dissolving agent solution to be dissolved; and starting a pressurizing pump on the ocean platform 1 to pressurize towards the inlet end of the submarine pipeline 3, namely pressurizing towards the rear end of the pipe cleaner 4, if the pressure is not increased, the pipe cleaner 4 can move forwards, the blockage is successfully released, if the pressure is increased all the time and reaches the highest point of the pressure borne by the submarine pipeline 3, the pressurizing is stopped to avoid damaging the submarine pipeline 3, the pipe cleaner 4 is judged to be still blocked and the blockage is still failed to be released, and the steps of discharging liquid and dissolving scale are repeated to release the blockage again.
The positioning method after the pipe cleaner 4 is blocked can calculate the blocking position of the pipe cleaner 4 in the submarine pipeline 3 more accurately, so that the dosage of reagents such as a foaming agent, a scale dissolving agent and the like required can be controlled more accurately, waste caused by excessive foaming agent and scale dissolving agent and corrosion of the inner wall of the submarine pipeline 3 caused by excessive scale dissolving agent can be avoided, meanwhile, the phenomenon that liquid cannot be completely discharged due to insufficient dosage of the foaming agent to dilute the scale dissolving agent can be avoided, and blockage release failure caused by insufficient dosage of the scale dissolving agent can be avoided.
The scale dissolver is required to be prepared into a scale dissolver solution with a certain concentration, and then the scale dissolver solution can be injected into the submarine pipeline 3 through the coiled tubing 6. The amount of the foaming agent is determined according to the volume of liquid in the submarine pipeline 3 at the front end of the pipe cleaner 4, when the pipe cleaner is blocked for the first time, the volume of the liquid in the submarine pipeline 3 at the front end of the pipe cleaner 4 is the volume from the front end of the pipe cleaner 4 to the outlet end of the submarine pipeline 3 in the submarine pipeline 3, if the first scale dissolving fails in the step S5, the liquid in the submarine pipeline 3 at the front end of the pipe cleaner 4 is the volume of the injected scale dissolving agent solution, and the amount of the foaming agent used at the moment is calculated according to the volume of the scale dissolving agent solution.
The steps S3 and S4 also comprise the following steps:
s31: calculating the using amount of a cleaning agent and preparing a cleaning agent solution according to the volume from the front end of a pipe cleaner 4 in the submarine pipeline 3 to the outlet end of the submarine pipeline 3, and injecting the prepared cleaning agent solution into the submarine pipeline 3 through a coiled tubing 6 for pre-cleaning;
s32: and (4) calculating a required foaming agent according to the using amount of the cleaning agent solution in the step (S31), injecting the foaming agent into the submarine pipeline 3 through the continuous oil pipe 6 for foaming, pumping nitrogen into the submarine pipeline 3 through the continuous oil pipe 6 to empty the foam, and then performing the step (S4).
The steps S31 and S32 are cleaning operations, in order to allow the scale dissolving agent to react with the sediment 5 sufficiently, the detergent is used to clean the sediment 5 and the oil stains attached to the surface of the submarine pipeline 3 after the liquid in the submarine pipeline 3 at the front end of the pipe cleaner 4 is emptied, and the detergent solution after the use is emptied by using the foaming agent and nitrogen gas so as to perform the subsequent scale dissolving operation. When the pipe cleaner 4 is blocked for the first time, the scale dissolving agent is used for thoroughly cleaning oil stains on the submarine pipeline 3 at the front end of the pipe cleaner 4, so that the pipe cleaner 4 can not be cleaned any more if blocked again after the blockage is released. If the submarine pipeline 3 at the front end of the cleaning device 4 is not completely cleaned in the first cleaning operation and only the sediments 5 falling off from the front end of the cleaning device 4 are cleaned, the cleaning operation needs to be carried out again when the cleaning device 4 is blocked again.
In the step S2, the submarine pipeline 3 includes a first vertical pipe section 31 with a top end inlet connected with the ocean platform 1, a first vertical pipe section 31 with a top end outlet connected with the floating production oil storage and drainage device 2, and a horizontal pipe section 32 arranged between the first vertical pipe section 31 and the second vertical pipe section 33;
if the cleaning pig 4 is jammed in the horizontal pipe section 32, as shown in fig. 2, the volume of the prepared scale dissolver solution is the volume between the front end of the cleaning pig 4 in the horizontal pipe section 32 and the joint of the horizontal pipe section 32 and the second vertical pipe section 33, so that the liquid level 7 of the scale dissolver solution is slightly higher than that of the horizontal pipe section 32; if the pig 4 is stuck in the second vertical pipe section 33, the volume of the prepared scale dissolver solution is not larger than the volume between the front end of the pig 4 in the second vertical pipe section 33 and the outlet at the top end of the second vertical pipe section 33.
The method is mainly aimed at the blockage of the cleaning pigs 4 due to the deposits 5, generally because the deposits 5 scraped off by the cleaning pigs 4 are accumulated in front of the cleaning pigs 4 to block the movement of the cleaning pigs 4, and possibly the deposits 5 on the inner side wall of the submarine pipeline 3 are more, so that the cleaning is difficult. When the pipe cleaner 4 blocks in the horizontal pipe section 32, the horizontal pipe section 32 at the front end of the pipe cleaner 4 is filled with the scale dissolving agent and the liquid level of the scale dissolving agent in the second vertical pipe section 33 is higher than that of the pipe cleaner 4, so that the sediment 5 of the blocked pipe cleaner 4 at the front end of the pipe cleaner 4 is fully immersed in the scale dissolving agent, the second vertical pipe section 33 is not required to be fully filled with the scale dissolving agent, the use level of the scale dissolving agent is saved, and the corrosion of the scale dissolving agent to the submarine pipeline 3 is reduced. When the pig 4 jams in the second vertical pipe section 33, the dosage of the scale dissolver only needs to submerge the detached deposit 5.
In the step S3, an outlet at the top end of the second vertical pipe section 33 is communicated with a sump oil chamber in the floating production oil storage and drainage device 2, and foam in the submarine pipeline 3 at the front end of the pipe cleaner 4 is discharged into the sump oil chamber after being filled with nitrogen.
After the foaming agent is injected, the liquid at the front end of the pipe cleaner 4 in the submarine pipeline 3 foams, the foam is discharged out of the submarine pipeline 3 after the nitrogen is injected, and the discharged foam is collected by utilizing a sump oil tank originally arranged in the floating production oil storage and discharge device 2.
In the step S3, a sampling position is provided on a connection pipeline between the outlet at the top end of the second vertical pipe section 33 and the sump oil tank, and it can be determined that no foam is present in the sampling position after continuous sampling.
In the step S3, a sampling position is arranged on a connecting pipeline between the outlet at the top end of the second vertical pipe section 33 and the sump oil tank, and it can be determined that the foam is discharged when no foam is continuously sampled in the sampling position.
The sampling position can be provided with a ball valve, the ball valve is opened periodically, and the situation that the foam is emptied is judged after no continuous foam is observed.
Example 3
This embodiment includes the following features in addition to the features described in embodiment 1:
the foaming agent comprises 15 percent (mass fraction) of cocoyl propyl hydroxysulfobetaine, 5 percent (mass fraction) of dodecyl imidazoline, 3 percent (mass fraction) of alkyl polyether ammonium oxide, 1 percent (mass fraction) of ethanol, 0.5 percent (mass fraction) of sodium formate solution and the balance of water; the amount of foaming agent is 500mg/L depending on the volume of liquid in the subsea pipe 3 in front of the pig 4.
The scale dissolver solution comprises 10 percent (mass fraction) of HCl, 5 percent (mass fraction) of HF, 2 percent of corrosion inhibitor and the balance of water.
The water used in the preparation of the scale dissolver solution can be replaced by seawater and other qualities. Thus, precious fresh water at sea can be saved.
The cleaning agent is a multifunctional cleaning agent BH-QXJ-01.
Example 4
The foaming agent comprises 25 percent (mass fraction) of cocoyl propyl hydroxysulfobetaine, 10 percent (mass fraction) of dodecyl imidazoline, 15 percent (mass fraction) of alkyl polyether ammonium oxide, 3 percent (mass fraction) of isopropanol, 1 percent (mass fraction) of sodium silicate solution and the balance of water; the amount of foaming agent used is 100mg/L, depending on the volume of liquid in the subsea pipe 3 at the front end of the pig 4.
The scale dissolver solution comprises 10 percent (mass fraction) of HCl, 5 percent (mass fraction) of HF, 2 percent of corrosion inhibitor and the balance of water.
Example 5
The foaming agent comprises 20 percent (mass fraction) of cocoyl propyl hydroxysulfobetaine, 8 percent (mass fraction) of dodecyl imidazoline, 8 percent (mass fraction) of alkyl polyether ammonium oxide, 1 percent (mass fraction) of ethylene and glycol respectively, 0.8 percent (mass fraction) of sodium sulfate solution and the balance of water; the amount of foaming agent is 300mg/L depending on the volume of liquid in the subsea pipe 3 in front of the pig 4.
The scale dissolver solution comprises 10 percent (mass fraction) of HCl, 5 percent (mass fraction) of HF, 2 percent of corrosion inhibitor and the balance of water.
It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. A positioning method after blocking of a pipe cleaner is characterized by comprising the following steps:
s1.1: according to various physical parameters of oil, gas and water conveyed in a submarine pipeline in the production process, the density rho of the oil, gas and water is calculated, and the calculation formula is as follows:
G t ＝ρ o +ρ ng R p +ρ w V w
s1.2: by calculating the average pressure drop in the subsea conduit
Calculating the end pressure P of the path of the subsea pipeline cleaned by the pig 2 So as to calculate the mean pressure in the path of the subsea pipeline cleaned by the pig>
The specific process is as follows:
s1.3: according to the temperature T of the inlet end of the submarine pipeline 1 And temperature of the outlet endDegree T 2 Calculating average temperature in subsea pipelines
S1.4: according to the mean pressure in the submarine pipeline
And the mean temperature->
Calculating the actual volume of oil, gas and water in the submarine pipeline
Thereby calculating the nominal flow Q in the vertical pipe section in the submarine pipeline Is perpendicular to ：
S1.5: using nominal flow Q of the pig in the vertical pipe section Is perpendicular to Calculating the flow velocity v of the pipe cleaner in the vertical pipe section Is perpendicular to ：
S1.6: according to the tip pressure P 2 And pressure P at the outlet end of the subsea pipe conduit O Calculating the mean pressure
As average pressure of a horizontal section of a subsea pipeline:
s1.7: according to the average pressure of horizontal pipe sections in submarine pipelines
And average temperature in a subsea pipeline>
Calculating the actual volume of oil, gas and water in a horizontal pipe section in the submarine pipeline>
Thereby calculating the nominal flow Q level in the horizontal section of the subsea pipeline:
s1.8: vertically calculating the flow velocity vpvel of the pipe pig in the horizontal pipe section by utilizing the nominal flow Q in the horizontal pipe section in the submarine pipeline:
s1.9: calculating the position of the cleaning pig in the subsea pipeline according to the time the cleaning pig enters the subsea pipeline and the speed of movement of the cleaning pig in the subsea pipeline:
2. a method for releasing blockage of a pipe cleaner is characterized by comprising the following steps:
s1: positioning a pig using the positioning method after pig jamming as claimed in claim 1;
s2: after the position of a pipe cleaner is determined, the coiled tubing is stretched into the submarine pipeline until an outlet of the coiled tubing reaches the position where a scale block is peeled off from the front end of the pipe cleaner, meanwhile, the required consumption of a foaming agent is calculated according to the volume of liquid in the submarine pipeline at the front end of the pipe cleaner, and the required consumption of a scale dissolving agent is calculated according to the volume of the submarine pipeline at the front end of the pipe cleaner;
s3: injecting a certain amount of foaming agent into the submarine pipeline through the coiled tubing for foaming, and pumping nitrogen into the submarine pipeline through the coiled tubing to empty the foam;
s4: preparing a scale dissolving agent solution according to the calculated dosage of the scale dissolving agent, injecting the prepared scale dissolving agent solution into the submarine pipeline through the coiled tubing, and reacting for a certain time;
s5: starting a pressurizing pump to pressurize the submarine pipeline at the rear end of the pipe cleaner, if the pressure is normal, releasing the blockage successfully, continuing to operate the pipe cleaner, if the pressure of the submarine pipeline at the front end of the pipe cleaner continues to rise to the highest point in the pressurizing process, releasing the blockage unsuccessfully, and repeating the steps S3 and S4;
s6: and (5) after the blockage is successfully released in the step (S5), the pipe cleaner continues to operate, if the pipe cleaner is blocked again, the steps (S1) to (S5) are repeated until the pipe cleaner reaches the tail end of the submarine pipeline to finish the pipe cleaning operation of all the positions of the submarine pipeline.
3. The method for unfreezing a blocked pig according to claim 2, further comprising the following steps between the steps S3 and S4:
s31: calculating the using amount of a cleaning agent and preparing a cleaning agent solution according to the volume from the front end of a pipe cleaner in the submarine pipeline to the outlet end of the submarine pipeline, and injecting the prepared cleaning agent solution into the submarine pipeline through a coiled tubing for pre-cleaning;
s32: and (4) calculating a required foaming agent according to the using amount of the cleaning agent solution in the step S31, injecting the foaming agent into the submarine pipeline through the coiled tubing for foaming, pumping nitrogen into the submarine pipeline through the coiled tubing to empty the foam, and then performing the step S4.
4. The method for releasing the stuck pipe pig according to claim 2, wherein in the step S2, the submarine pipeline comprises a first vertical pipe section with a top end inlet connected with the ocean platform, a first vertical pipe section with a top end outlet connected with the floating production oil storage and drainage device, and a horizontal pipe section arranged between the first vertical pipe section and the second vertical pipe section;
if the pipe cleaner is blocked in the horizontal pipe section, the volume of the prepared scale dissolving agent solution is the volume from the front end of the pipe cleaner in the horizontal pipe section to the joint between the horizontal pipe section and the second vertical pipe section; and if the pipe cleaner is blocked in the second vertical pipe section, the volume of the prepared scale dissolving agent solution is not more than the volume from the front end of the pipe cleaner in the second vertical pipe section to the outlet at the top end of the second vertical pipe section.
5. The method for releasing the blocked pipe pig according to claim 2, wherein in the step S3, the outlet at the top end of the second vertical pipe section is communicated with a sump oil chamber in the floating production oil storage and release device, and the foam in the submarine pipeline at the front end of the pipe pig is discharged into the sump oil chamber after being filled with nitrogen.
6. The method for releasing the blocked pipeline pig according to claim 5, wherein in the step S3, a sampling position is arranged on a connecting pipeline between the outlet at the top end of the second vertical pipe section and the sump oil tank, and the situation that no foam exists in the sampling position after continuous sampling can be judged to be discharged.
7. The method for releasing seized pipe pig after seizing according to claim 2, wherein the foaming agent comprises cocoyl propyl hydroxy sulfobetaine 15-25% (mass fraction), dodecyl imidazoline 5-10% (mass fraction), alkyl polyether ammonium oxide 3-15% (mass fraction), organic solution 1-3% (mass fraction), inorganic salt solution 0.5-1% (mass fraction), and water in balance; the amount of foaming agent is 100-500mg/L, depending on the volume of liquid in the subsea pipeline at the front end of the pig.
8. The method for releasing stuck pipe pig according to claim 2, characterized in that the detergent solution comprises 10% (mass fraction) of HCl and 5% (mass fraction) of HF +2% of corrosion inhibitor, the rest being water.
9. The method for freeing a pig after jamming according to claim 8, characterized in that the water used in the preparation of the detergent solution can be replaced by sea water or the like.
10. The method for releasing the stuck pig according to claim 1, wherein the cleaning agent is a multifunctional cleaning agent BH-QXJ-01.
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| CN202211565975.XA CN115982537A (en) | 2022-12-07 | 2022-12-07 | Positioning method and releasing method after pipe cleaner jamming |
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