CN106194165A - Gas hydrates blocking monitoring device and method in the test of deep water gas well - Google Patents

Abstract

The present invention relates to gas hydrates blocking monitoring device in a kind of deep water gas well test, it includes downhole data acquiring and transmission system, platform control system and hydrate inhibitor automatic injection system.The temperature, pressure data of fluid in downhole data acquiring and transmission system real-time monitoring and test tubing string, and transfer data to platform control system；Gas hydrates stopping state in test string is carried out calculating assessment by platform control system, send corresponding early warning signal, and the instruction of injection hydrate inhibitor is sent according to tubing string blockage, start corresponding hydrate inhibitor injection pump, inject pipeline and hydrate inhibitor fill nipple by hydrate inhibitor, in test string, inject hydrate inhibitor.The present invention can be in deep water gas well test jobs, position, the Hydrate Plugging order of severity that in test string, Hydrate Plugging occurs and occur the completely plugged required time to calculate, and can instruct the formulation of hydrate prophylactico-therapeutic measures.

Description

Gas hydrates blocking monitoring device and method in the test of deep water gas well

Technical field

The invention belongs to ocean deepwater oil-gas exploration and development field, in particular it relates to natural in a kind of deep water gas well test Gas hydrate blocking monitoring device and method.

Background technology

Along with petering out of Land petroleum resource, exploration and development activity progressively turns to deep water field, deep water field new Increase oil gas proved reserves the contribution of newly-increased oil gas proved reserves overall in global range is persistently risen.Party eighteen major report is bright Really propose to build " ocean power " strategy, strengthen the exploitation of Marine oil and gas resource, significant for building ocean power. Can run into a lot of technological challenge in deep water hydrocarbon drilling operation, wherein under the conditions of cryogenic high pressure, gas hydrates generate will It is drilled well operations, test jobs, oil-gas gathering and transportation etc. to deep water and brings all many challenges.

The test of deep water gas well is understanding oil-gas reservoir, the important cargo handling operation of assessment reservoir potentiality.The most conventional Deep water gas well test system is as it is shown in figure 1, critical piece is deep water gas well test string 101 and is installed on test string Relevant auxiliary equipment, relevant auxiliary equipment mainly includes testing tree 102, blowout prevention valve 103 and flowing control 104 under water, under water Testing tree 102 is arranged on subsea wellheads, and blowout prevention valve 103 is positioned at the test string on testing tree top under water, flowing control 104 It is installed on well head waterborne (top of deep water gas well test string 101), connects with the outflow tube line on test platform, wellhead temperature Formation fluid temperature, pressure parameter is monitored by meter 105 and well head pressure meter 106, and formation fluid is through blowout oil nozzle 107 He Being for further processing after well head effusion meter 108 (such as gas-liquid separation, burning etc.), these auxiliary equipments are for controlling formation fluid Flow out, pressure in test string is controlled, prevents the generation of gas blowout accident, and the temperature, pressure of convection cell and flow are carried out Metering.

In proper testing operation process, stratum produced fluid enters test string, is travelled up to by test string Test platform, carries out gas-liquid separation process to the fluid flowed out on platform, and isolated gas is burnt by torch, point The fluid storage separated out is in storage tank corresponding on platform.

Yet with the existence of deep-water low-temperature condition of high voltage, in test process, often generate natural in test string Gas hydrate, blocks tubing string, affects being normally carried out of test jobs.Existing technical basis hydrate generates Phase Equilibrium theory, It is only capable of and simply preliminarily judges in test string system, which position disclosure satisfy that the temperature, pressure condition that hydrate generates, but It is cannot to determine when where can cause Hydrate Plugging, and the order of severity of Hydrate Plugging occurs.WANG Zhi-yuan Deng proposing according to hydrate generation Phase Equilibrium theory, calculate in conjunction with pit shaft thermobaric field, determine water in deep water gas well test process Compound formation zone (Journal of Hydrodynamics.2014,26 (4): 840-847).Patent CN104088623A depends on Generate Phase Equilibrium theory according to hydrate, determine hydrate formation zone in test string, and give hydrate preventing and treating side accordingly Method, but where and when this patent can cause Hydrate Plugging in cannot be used for monitoring and analyzing test string, and there is water The order of severity of compound blocking.Patent CN104343416A discloses a kind of deep water gas well test system and method for testing, proposes Generate Phase Equilibrium theory according to hydrate, determine hydrate formation zone in test string, and then use the preventing and treating of downhole choke method Hydrate, where and when this patent can cause Hydrate Plugging, and occur in can not being used for monitoring and analyze test string The order of severity of Hydrate Plugging.Patent CN104895560A disclose a kind of deep water test wellbore pressure, temperature field simulation and Hydrate Prediction method, this patent is only capable of judging that in test pit shaft, where meets the Temperature-pressure Conditions that hydrate generates, without reference to To problems such as hydrate generating rate, hydrate deposit blockings, it is impossible to where and when can in being used for monitoring and analyze test string Cause Hydrate Plugging, and the order of severity of blocking.

Summary of the invention

For overcoming the defect existing for prior art, the invention provides gas hydrates in a kind of deep water gas well test Blocking monitoring device and method.By monitoring down-hole temperature and pressure data in real time, in conjunction with Hydrate Plugging prediction proposed by the invention Method, determines the position that Hydrate Plugging occurs in test string, it is judged that the Hydrate Plugging order of severity, calculate occur the most stifled Time needed for plug, send early warning signal, in trend test string, inject hydrate inhibitor, it is ensured that the test of deep water gas well is made Industry is safe and efficient to be carried out.

For solving above-mentioned technical problem, the technical solution adopted in the present invention is as follows:

Gas hydrates blocking monitoring device in the test of deep water gas well, including: downhole data acquiring and transmission system, platform Control system and hydrate inhibitor automatic injection system.Fluid in downhole data acquiring and transmission system real-time monitoring and test tubing string Temperature, pressure data, and the temperature monitored, pressure data are transferred to platform control system；Platform control system is to survey In test tube post, the gas hydrates blocking order of severity, tubing string are completely plugged required time and occur completely plugged at first Position carries out calculating assessment, sends corresponding early warning signal, and sends injection hydrate inhibitor according to tubing string blockage Instruction；The instruction that hydrate inhibitor automatic injection system sends according to platform control system, starts the suppression of corresponding hydrate Agent injection pump, injects pipeline and hydrate inhibitor fill nipple by hydrate inhibitor, injects hydration in test string Thing inhibitor.

Relative to prior art, beneficial effects of the present invention is as follows: in deep water gas well test Hydrate Prediction and preventing and treating side Face, prior art is only capable of and generates Phase Equilibrium theory according to hydrate, it was predicted that in tubing string, where can there are beneficially hydrate life The Temperature-pressure Conditions become, and can not judge to be formed Hydrate Plugging, and the position that occurs of Hydrate Plugging and time, and The present invention is by the monitoring to downhole temperature pressure data, in conjunction with Hydrate Plugging determination methods proposed by the invention, permissible To in deep water gas well test jobs, position, the Hydrate Plugging order of severity that in test string, Hydrate Plugging occurs, occur Time needed for full blocking calculates, and can instruct the formulation of hydrate prophylactico-therapeutic measures, includes whether that injecting hydrate presses down Preparation and the determination etc. of hydrate inhibitor injection phase.

Accompanying drawing explanation

Fig. 1 is deep water gas well test system schematic in prior art.

Fig. 2 is gas hydrates blocking monitoring device schematic diagram in the test of deep water gas well.

Fig. 3 is gas hydrates blocking monitoring method schematic diagram in the test of deep water gas well.

In figure: 101, deep water gas well test string；102, testing tree under water；103, blowout prevention valve；104, flowing controls head； 105, wellhead temperature meter；106, well head pressure meter；107, blowout oil nozzle；108, well head effusion meter；201a, the first temperature/pressure sensor Group；201b, the second temperature/pressure sensor group；201c, the 3rd temperature/pressure sensor group；202, optical cable；301, optical fiber interface；302, photoelectricity Demodulator；303, computer；304, alarm；305, hydrate inhibitor storage tank；306, signal actuator；307a, first Hydrate inhibitor injection pump；307b, the second hydrate inhibitor injection pump；307c, trihydrate inhibitor injection pump； 308a, the first hydrate inhibitor inject pipeline；308b, the second hydrate inhibitor inject pipeline；308c, trihydrate press down Preparation injects pipeline；309a, the first hydrate inhibitor fill nipple；309b, the second hydrate inhibitor fill nipple.

Detailed description of the invention

As in figure 2 it is shown, gas hydrates blocking monitoring device in the test of deep water gas well, including: downhole data collection passes Communication system, platform control system and hydrate inhibitor automatic injection system.Downhole data acquiring and transmission system monitors survey in real time The temperature of fluid, pressure data in test tube post, and the temperature monitored, pressure data are transferred to platform control system；Platform Control system is completely plugged required time to the gas hydrates blocking order of severity, tubing string in test string and sends out at first Raw completely plugged position carries out calculating assessment, sends corresponding early warning signal, and sends injection water according to tubing string blockage The instruction of compound inhibitors；The instruction that hydrate inhibitor automatic injection system sends according to platform control system, starts corresponding Hydrate inhibitor injection pump, inject pipeline and hydrate inhibitor fill nipple by hydrate inhibitor, to testing tube Hydrate inhibitor is injected in post.

Downhole data acquiring and transmission system, including: the first temperature/pressure sensor group 201a, the second temperature/pressure sensor group 201b, 3rd temperature/pressure sensor group 201c and optical cable 202.First temperature/pressure sensor group 201a is installed on above test layer position, the second temperature and pressure Sensor group 201b is installed under water below testing tree 102, and spacing 10 meters, the 3rd temperature/pressure sensor group 201c is installed on away from sea Below at 400 meters；First temperature/pressure sensor group 201a, the second temperature/pressure sensor group 201b and the 3rd temperature/pressure sensor group 201c are used In the temperature and pressure data of monitoring present position deep water gas well test string 101, the temperature, the pressure data that monitor pass through light Cable 202 is transferred to platform control system.

Platform control system, including: optical fiber interface 301, photoelectricity demodulator 302, computer 303 and alarm 304.Optical fiber Interface 301 is connected with optical cable 202, and photoelectricity demodulator 302 is connected with optical fiber interface 301 by optical fiber, photoelectricity demodulator 302 and Computer 303 is connected, and computer is connected with alarm 304；The downhole temperature pressure that downhole data acquiring and transmission system collects Data are transmitted to photoelectricity demodulator 302 by optical cable 202 and optical fiber interface 301, and photoelectricity demodulator 302 converts optical signals to electricity Signal, the signal of telecommunication is transferred to computer 303, the downhole data that computer 303 monitors according to downhole data acquiring and transmission system, Gas hydrates blockage in deep water gas well test string 101 is carried out computational analysis, it is judged that Hydrate Plugging occurs Position, blocks harmful grade, and computed range occurs completely plugged required time, sends alarm command and hydrate inhibitor note Enter instruction, after alarm 304 receives alarm command, send the early warning signal of appropriate level, point out operating personnel's deep water gas well In test string 101, the Hydrate Plugging order of severity and distance tubing string are by the completely plugged time still remaining of hydrate.

Early warning signal grade classification is as follows: hydrate deposits attachment on deep water gas well test string 101 inwall, causes pipe The effective internal diameter of post reduces, and characterizes in deep water gas well test string 101 as it is shown on figure 3, reduce degree with the effective internal diameter of test string The Hydrate Plugging order of severity, is divided into four grades by early warning signal.If hydrate deposit attachment causes test string effectively to manage Footpath (d_e) it is reduced to: 0.7d_ti≤d_e<0.9d_ti, then carrying out one-level warning, alarm 304 sends one-level early warning signal, wherein d_ti Initial inside diameter for deep water gas well test string 101；If 0.6d_ti≤d_e<0.7d_ti, then secondary alarm, alarm 304 are carried out Go out two grades of early warning signals；If 0.4d_ti≤d_e<0.6d_ti, then carrying out three grades of warnings, alarm 304 sends three grades of early warning signals；If d_e<0.4d_ti, then carrying out level Four warning, alarm 304 sends level Four early warning signal.

Hydrate inhibitor automatic injection system, including: hydrate inhibitor storage tank the 305, first hydrate inhibitor is noted Enter pump 307a, the second hydrate inhibitor injection pump 307b, trihydrate inhibitor injection pump 307c, the first hydrate suppression Pipeline 308a is injected in agent, the second hydrate inhibitor injects pipeline 308b and trihydrate inhibitor injects pipeline 308c.Water Compound inhibitors storage tank 305 is arranged on test platform, is used for storing hydrate inhibitor, such as methanol, ethylene glycol etc.；Hydrate Inhibitor storage tank 305 is respectively by pipeline and the first hydrate inhibitor injection pump 307a, the second hydrate inhibitor injection pump 307b and trihydrate inhibitor injection pump 307c is connected, to the first hydrate inhibitor injection pump 307a, the second hydrate Inhibitor injection pump 307b and trihydrate inhibitor injection pump 307c provides hydrate inhibitor；Signal actuator 306 Being connected with the computer 303 of platform control system, the instruction sent according to platform control system, to the first hydrate inhibitor Injection pump 307a, the second hydrate inhibitor injection pump 307b and trihydrate inhibitor injection pump 307c operate, bag Include and open pump and termination of pumping；First hydrate inhibitor fill nipple 309a is installed on the deep water gas well test at below mud line 600 meters On tubing string 101；Second hydrate inhibitor fill nipple 309b is installed on the deep water gas well test string at 300 meters of below sea On 101；First hydrate inhibitor injects pipeline 308a and connects the first hydrate inhibitor injection pump 307a and the first hydrate Inhibitor fill nipple 309a, the second hydrate inhibitor injects pipeline 308b and connects the second hydrate inhibitor injection pump 307b Testing tree 102 under water, trihydrate inhibitor inject pipeline 308c connect trihydrate inhibitor injection pump 307c and Second hydrate inhibitor fill nipple 309b.

First hydrate inhibitor injection pump 307a, the second hydrate inhibitor injection pump 307b and trihydrate suppression Agent injection pump 307c works alone, and can carry out starting or termination of pumping simultaneously, and make following concrete regulation.

If the Hydrate Plugging order of severity reaches three grades and above rank (occurs three grades in deep water gas well test string 101 Early warning signal and level Four early warning signal), then start corresponding hydrate inhibitor injection pump, to deep water gas well test string 101 Interior injection hydrate inhibitor, idiographic flow is as follows.

If 1. the fastest position of deep water gas well test string 101 effective internal diameter reduction is positioned at the lower section of testing tree 102 under water, Then start the first hydrate inhibitor injection pump 307a, surveyed to deep water gas well by the first hydrate inhibitor fill nipple 309a Test tube post 101 injects hydrate inhibitor.

If 2. the fastest position of test string effective internal diameter reduction is positioned at testing tree 102 and the second hydrate inhibitor under water Between fill nipple 309b, then start the second hydrate inhibitor injection pump 307b, by testing tree 102 under water to deep water gas well Test string 101 injects hydrate inhibitor.

If 3. the effective internal diameter of test string reduce the fastest position be positioned at the second hydrate inhibitor fill nipple 309b with On, then start trihydrate inhibitor injection pump 307c, by the second hydrate inhibitor fill nipple 309b to deep water gas Well test string 101 injects hydrate inhibitor.

Gas hydrates blocking monitoring method in the test of deep water gas well, uses gas water in the test of above-mentioned deep water gas well Compound blocking monitoring device, step is as follows:

1. gas production Q is measured by well head effusion meter 108_gWith aquifer yield Q_w, measure well head stream by wellhead temperature meter 105 Temperature T_wh, measure resulting fluid pressure p by well head pressure meter 106_wh。

2. the first temperature/pressure sensor group 201a, the second temperature/pressure sensor group 201b and the 3rd temperature/pressure sensor group 201c are utilized Measure at respective depth fluid temperature (F.T.) T1, T2, T3 and pressure p 1, p2, p3 in deep water gas well test string 101 respectively.

3. fluid temperature (F.T.) pressure distribution in deep water gas well test string is calculated.1. the data obtained and are 2. measured according to step And test string parameter, geothermal gradient, the depth of water, well depth, casing programme parameter, formula (1) calculate deep water gas well test string Pressure distribution in 101.

$-\frac{dp}{ds}=\frac{\&part;}{\&part;t}\left({\mathrm{A\&rho;}}_m{v}_m\right)+\frac{\&part;}{\&part;s}\left({\mathrm{A\&rho;}}_m{v}_m^2\right)+{\mathrm{Ag\&rho;}}_{m}cos\mathrm{\&alpha;}+\left|f_F\frac{{\mathrm{\&rho;}}_m{v}_m^2}{2d_e}\right|---\left(1\right)$

In formula, p is pressure distribution in test string；S is the distance to test layer position；T is the time；A is that test string has Effect area of passage；ρ_mFor fluid mixture average density in test string；v_mFor fluid mixture mean flow rate；f_FFor frictional resistance system Number；d_eFor the effective internal diameter of test string.

Fluid temperature (F.T.) distribution in deep water gas well test string 101 is calculated by formula (2).

$\frac{{\mathrm{dT}}_f}{ds}=\frac{2{\mathrm{\&pi;r}}_{to}{U}_{to}{k}_e}{w_m{C}_m(k_e+r_{to}{T}_D{U}_{to})}(T_f-T_{ei})+\frac{r_{hf}\mathrm{\&Delta;}h}{w_m{C}_m{M}_h}---\left(2\right)$

In formula, T_fFor fluid temperature (F.T.) in test string；C_mFor fluid mixture mean heat capacity；r_toFor test string external diameter； U_toFor pit shaft overall heat-transfer coefficient；k_eFor formation thermal conductivity；w_mFor fluid mixture mass flow；T_DFor dimensionless temperature；T_ei For stratum original temperature；Δ h is that gas hydrates generate heat；r_hfFor gas hydrates generating rate；M_hFor gas water Compound molal weight.

4. gas hydrates formation zone in deep water gas well test string is determined.Generate equal according to gas hydrates Weighing apparatus theory, calculates hydrate at different depth and generates temperature, when fluid temperature (F.T.) generates temperature less than hydrate, in test string Hydrate can be generated, thereby determine that the formation zone of gas hydrates in deep water gas well test string.

5. the generating rate of gas hydrates at different depth is calculated in deep water gas well test string.4. described in step Have hydrate in gas hydrates formation zone to generate, but the gas hydrates generated cause test string blocking to need Want the regular hour, utilize equation below to calculate the life of gas hydrates at different depth in deep water gas well test string 101 Become speed.

$r_{hf}={\mathrm{uA}}_s{k}_1\exp (-\frac{k_2}{T_f})\left({\mathrm{\&Delta;T}}_{sub}\right)---\left(3\right)$

In formula, u is coefficient；A_sFor gas liquid interfacial area；k₁And k₂For reaction constant；ΔT_subFor degree of supercooling.

6. effective internal diameter of deep water gas well test string is calculated.Generate gas hydrates some can deposit attachment On test string inwall, form the hydrate layer of constantly growth so that effective internal diameter of deep water gas well test string 101 is continuous Reducing, hydrate layer thickness is calculated by formula (4), and effective internal diameter of deep water gas well test string 101 is counted by formula (5) Calculate.

${\mathrm{\&delta;}}_h={\&Integral;}_0^t\frac{{\mathrm{uk}}_1{\mathrm{\&Delta;T}}_{sub}}{{\mathrm{\&rho;}}_h}{e}^{-k_2/T_f}dt---\left(4\right)$

$d_e=d_{ti}-2{\mathrm{\&delta;}}_h=d_{ti}-2{\&Integral;}_0^t\frac{{\mathrm{uk}}_1{\mathrm{\&Delta;T}}_{sub}}{{\mathrm{\&rho;}}_h}{e}^{-k_2/T_f}dt---\left(5\right)$

In formula, δ_hFor hydrate layer thickness；ρ_hFor hydrate density；d_tiFor test string original inner diameter.

7. judge the Hydrate Plugging order of severity in test string, determine the position that Hydrate Plugging occurs at first, calculate Test string is by the completely plugged required time of hydrate.By step 1.-6. obtain different depth deep water gas well test string 101 Effective internal diameter situation over time, as shown in Figure 3, it can be seen that along with constantly giving birth on hydrate layer on pipe string internal wall Long, the effective internal diameter of tubing string constantly reduces.Deep water gas well test string 101 quilt is characterized by test string effective internal diameter situation of change The order of severity of Hydrate Plugging, then may determine that the Hydrate Plugging order of severity in test string according to Fig. 3, at first water occur The position of compound blocking and test string are by the hydrate completely plugged required time.As it is shown on figure 3, away from 150 meters of sea The effective internal diameter of test string of depth reduces the fastest, as shown in curve A, represents that at this, Hydrate Plugging situation is the most serious, Can reach three grades of blockings during 28h, alarm will send three grades of early warning signals, owing to the effective internal diameter of tubing string reduces the fastest position (150 meters of depths) is positioned at the second hydrate inhibitor more than fill nipple 309b, therefore starts trihydrate inhibitor and injects Pump 307c, injects hydrate inhibitor from the second hydrate inhibitor fill nipple 309b.If it can also be seen that not from Fig. 3 In deep water gas well test string 101, inject hydrate inhibitor, then need the time of about 45 hours so that test string is by water Compound is completely plugged, and is occurred (position of blocking to occur at first at 150 meters of depths by the position that hydrate is completely plugged at first And required time is relevant with the many factors such as gas production, the depth of water).

8. according to step Calculation results 6. and 7., platform control system sends corresponding alarm command, makes warning Device 304 sends corresponding early warning signal.According to test string by the order of severity of Hydrate Plugging, early warning signal is divided into four Grade, as shown in Figure 3.If hydrate deposit attachment causes test string effective diameter of pipe (d_e) it is reduced to: 0.7d_ti≤d_e< 0.9d_ti, then alarm sends one-level early warning signal；If 0.6d_ti≤d_e<0.7d_ti, then alarm sends two grades of early warning signals；If 0.4d_ti≤d_e<0.6d_ti, then alarm sends three grades of early warning signals；If d_e<0.4d_ti, then alarm sends level Four early warning signal.

9. according to Hydrate Plugging early warning signal rank in test string, hydrate inhibitor automatic injection system rings Should.If there is three grades or level Four early warning signal, then platform control system sends hydrate inhibitor injection instruction, starts hydrate Inhibitor injection pump, injects hydrate inhibitor in deep water gas well test string 101.

If the effective internal diameter of deep water gas well test string 101 reduces the fastest position is positioned at the lower section of testing tree 102 under water, then Start the first hydrate inhibitor injection pump 307a, tested to deep water gas well by the first hydrate inhibitor fill nipple 309a Tubing string 101 injects hydrate inhibitor.

If the effective internal diameter of test string reduces the fastest position is positioned at testing tree 102 and the second hydrate inhibitor note under water Enter between joint 309b, then start the second hydrate inhibitor injection pump 307b, surveyed to deep water gas well by testing tree 102 under water Test tube post 101 injects hydrate inhibitor.

If the effective internal diameter of test string reduces the fastest position is positioned at the second hydrate inhibitor more than fill nipple 309b, Then start trihydrate inhibitor injection pump 307c, surveyed to deep water gas well by the second hydrate inhibitor fill nipple 309b Test tube post 101 injects hydrate inhibitor.

Claims (10)

1. a gas hydrates blocking monitoring device in the test of deep water gas well, including: downhole data acquiring and transmission system, flat Bench control system and hydrate inhibitor automatic injection system；It is characterized in that: downhole data acquiring and transmission system is monitored in real time The temperature of fluid, pressure data in test string, and the temperature monitored, pressure data are transferred to platform control system；Flat Bench control system is completely plugged required time and at first to gas hydrates the blocking order of severity, tubing string in test string Occur completely plugged position to carry out calculating assessment, send corresponding early warning signal, and send injection according to tubing string blockage The instruction of hydrate inhibitor；The instruction that hydrate inhibitor automatic injection system sends according to platform control system, starts phase The hydrate inhibitor injection pump answered, injects pipeline and hydrate inhibitor fill nipple by hydrate inhibitor, to test Hydrate inhibitor is injected in tubing string.

Gas hydrates blocking monitoring device in deep water gas well the most according to claim 1 test, it is characterised in that: well Lower data collection and transfering system, including: the first temperature/pressure sensor group, the second temperature/pressure sensor group, the 3rd temperature/pressure sensor group and Optical cable；First temperature/pressure sensor group is installed on above test layer position, and the second temperature/pressure sensor group is installed under water below testing tree, Spacing 10m, the 3rd temperature/pressure sensor group is installed on below sea at 400m；First temperature/pressure sensor group, the second temperature and pressure sensing Device group and the 3rd temperature/pressure sensor group, for monitoring the temperature and pressure data of present position deep water gas well test string, monitor Temperature, pressure data by optical cable transmission to platform control system.

3. gas hydrates blocking monitoring device in testing according to the deep water gas well described in claim 1-2, it is characterised in that: Platform control system, including: optical fiber interface, photoelectricity demodulator, computer and alarm.Optical fiber interface is connected with optical cable, light Electrical demodulator is connected with optical fiber interface by optical fiber, and photoelectricity demodulator is connected with computer, and computer is connected with alarm；Down-hole Downhole temperature, pressure data that data collection and transfering system collects are transmitted to photoelectricity demodulator by optical cable and optical fiber interface, Photoelectricity demodulator converts optical signals to the signal of telecommunication, and the signal of telecommunication is transferred to computer, and computer transmits according to downhole data collection The downhole data that system monitoring arrives, carries out computational analysis to gas hydrates blockage in deep water gas well test string, sentences The position that disconnected Hydrate Plugging occurs, blocks harmful grade, and computed range occurs completely plugged required time, sends alarm command And hydrate inhibitor injects instruction, after alarm receives alarm command, sending the early warning signal of appropriate level, prompting is made In industry personnel's deep water gas well test string, the Hydrate Plugging order of severity and distance tubing string be there remains by hydrate is completely plugged Time.

4. gas hydrates blocking monitoring device in testing according to the deep water gas well described in claim 1-3, it is characterised in that: Hydrate inhibitor automatic injection system, including: hydrate inhibitor storage tank, the first hydrate inhibitor injection pump, the second water Compound inhibitors injection pump, trihydrate inhibitor injection pump, the first hydrate inhibitor inject pipeline, the second hydrate presses down Preparation injects pipeline and trihydrate inhibitor injects pipeline.Hydrate inhibitor storage tank is arranged on test platform, is used for Storing hydrate inhibitor, hydrate inhibitor storage tank is respectively by pipeline and the first hydrate inhibitor injection pump, the second water Compound inhibitors injection pump and trihydrate inhibitor injection pump are connected, to the first hydrate inhibitor injection pump, the second water Compound inhibitors injection pump and trihydrate inhibitor injection pump provide hydrate inhibitor；Signal actuator and platform control The computer of system processed is connected, the instruction sent according to platform control system, to the first hydrate inhibitor injection pump, second Hydrate inhibitor injection pump and trihydrate inhibitor injection pump operate, including opening pump and termination of pumping；First hydrate Inhibitor fill nipple is installed on the deep water gas well test string at below mud line 600m；Second hydrate inhibitor injects and connects Head is installed on the deep water gas well test string at the 300m of below sea；First hydrate inhibitor injects pipeline and connects the first water Compound inhibitors injection pump and the first hydrate inhibitor fill nipple, the second hydrate inhibitor injects pipeline and connects the second water Compound inhibitors injection pump and under water testing tree, trihydrate inhibitor injects pipeline and connects the injection of trihydrate inhibitor Pump and the second hydrate inhibitor fill nipple.

5. gas hydrates blocking monitoring device in testing according to the deep water gas well described in claim 1-4, it is characterised in that: First hydrate inhibitor injection pump, the second hydrate inhibitor injection pump and trihydrate inhibitor injection pump independence work Make, can carry out starting or termination of pumping simultaneously.

6. gas hydrates blocking monitoring device in testing according to the deep water gas well described in claim 1-5, it is characterised in that: In deep water gas well test string, the Hydrate Plugging order of severity reaches three grades of early warning signals and level Four early warning signal, then start corresponding Hydrate inhibitor injection pump, in deep water gas well test string inject hydrate inhibitor.

7. gas hydrates blocking monitoring device in testing according to the deep water gas well described in claim 1-6, it is characterised in that: If the effective internal diameter of deep water gas well test string reduces the fastest position is positioned at the lower section of testing tree under water, then start the first hydrate Inhibitor injection pump, injects hydrate in deep water gas well test string by the first hydrate inhibitor fill nipple and suppresses Agent；If the effective internal diameter of test string reduce the fastest position be positioned under water testing tree and the second hydrate inhibitor fill nipple it Between, then start the second hydrate inhibitor injection pump, in deep water gas well test string, inject hydrate by testing tree under water Inhibitor；If the effective internal diameter of test string reduces the fastest position is positioned at more than the second hydrate inhibitor fill nipple, then open Dynamic trihydrate inhibitor injection pump, is injected in deep water gas well test string by the second hydrate inhibitor fill nipple Hydrate inhibitor.

8. gas hydrates blocking monitoring device in testing according to the deep water gas well described in claim 1-7, it is characterised in that: Causing test string effective diameter of pipe to reduce situation according to hydrate deposit attachment, early warning signal is divided into four grades: if 0.7d_ti≤ d_e<0.9d_ti, then alarm sends one-level early warning signal；If 0.6d_ti≤d_e<0.7d_ti, then alarm sends two grades of early warning signals； If 0.4d_ti≤d_e<0.6d_ti, then alarm sends three grades of early warning signals；If d_e<0.4d_ti, then alarm sends level Four early warning letter Number；Wherein: d_eFor test string effective diameter of pipe, d_tiInitial inside diameter for deep water gas well test string.

9. gas hydrates blocking monitoring device in testing according to the deep water gas well described in claim 1-8, it is characterised in that: The hydrate inhibitor used is methanol or ethylene glycol.

10. a gas hydrates blocking monitoring method in the test of deep water gas well, uses described deep of one of claim 1-9 Gas hydrates blocking monitoring device in the examination of aqueous vapor well surveying, it is characterised in that step is as follows:

1. by well head flowmeter survey gas production Q_gWith aquifer yield Q_w, measure fluid temperature uphole T by wellhead temperature meter_wh, logical Cross well head pressure meter metering resulting fluid pressure p_wh；

2. the first temperature/pressure sensor group, the second temperature/pressure sensor group and the 3rd temperature/pressure sensor group is utilized to measure respective depth respectively Fluid temperature (F.T.) T1, T2, T3 and pressure p 1, p2, p3 in place's deep water gas well test string.

3. calculate fluid temperature (F.T.) pressure distribution in deep water gas well test string, 1. and 2. measure according to step the data obtained and Test string parameter, geothermal gradient, the depth of water, well depth, casing programme parameter, calculated in deep water gas well test string by formula (1) and press Power is distributed；

$-\frac{dp}{ds}=\frac{\&part;}{\&part;t}\left({\mathrm{A\&rho;}}_m{v}_m\right)+\frac{\&part;}{\&part;s}\left({\mathrm{A\&rho;}}_m{v}_m^2\right)+{\mathrm{Ag\&rho;}}_{m}cos\mathrm{\&alpha;}+\left|f_F\frac{{\mathrm{\&rho;}}_m{v}_m^2}{2d_e}\right|---\left(1\right)$

In formula, p is pressure distribution in test string；S is the distance to test layer position；T is the time；A is the effective mistake of test string Flow area；ρ_mFor fluid mixture average density in test string；v_mFor fluid mixture mean flow rate；f_FFor the coefficient of friction resistance；d_e For the effective internal diameter of test string；

Fluid temperature (F.T.) distribution in deep water gas well test string is calculated by formula (2)；

$\frac{{\mathrm{dT}}_f}{ds}=\frac{2{\mathrm{\&pi;r}}_{to}{U}_{to}{k}_e}{w_m{C}_m(k_e+r_{to}{T}_D{U}_{to})}(T_f-T_{ei})+\frac{r_{hf}\mathrm{\&Delta;}h}{w_m{C}_m{M}_h}---\left(2\right)$

In formula, T_fFor fluid temperature (F.T.) in test string；C_mFor fluid mixture mean heat capacity；r_toFor test string external diameter；U_toFor Pit shaft overall heat-transfer coefficient；k_eFor formation thermal conductivity；w_mFor fluid mixture mass flow；T_DFor dimensionless temperature；T_eiFor stratum Original temperature；Δ h is that gas hydrates generate heat；r_hfFor gas hydrates generating rate；M_hRub for gas hydrates That quality；

4. gas hydrates formation zone in deep water gas well test string is determined；The reason that balances each other is generated according to gas hydrates Opinion, calculates hydrate at different depth and generates temperature, when fluid temperature (F.T.) generates temperature less than hydrate, can give birth in test string Become hydrate, thereby determine that the formation zone of gas hydrates in deep water gas well test string；

5. the generating rate of gas hydrates at different depth is calculated in deep water gas well test string；At the most described gas water In compound formation zone, have hydrate and generate, but when the hydrate generated causes test string blocking to need certain Between, utilize equation below to calculate in deep water gas well test string the generating rate of gas hydrates at different depth；

$r_{hf}={\mathrm{uA}}_s{k}_1\exp (-\frac{k_2}{T_f})\left({\mathrm{\&Delta;T}}_{sub}\right)---\left(3\right)$

In formula, u is coefficient；A_sFor gas liquid interfacial area；k₁And k₂For reaction constant；ΔT_subFor degree of supercooling；

6. effective internal diameter of deep water gas well test string is calculated；The hydrate generated some can deposit and be attached to test string On inwall, form the hydrate layer of constantly growth so that effective internal diameter of deep water gas well test string constantly reduces, hydrate layer Thickness is calculated by formula (4), and effective internal diameter of deep water gas well test string is calculated by formula (5)；

${\mathrm{\&delta;}}_h={\&Integral;}_0^t\frac{{\mathrm{uk}}_1{\mathrm{\&Delta;T}}_{sub}}{{\mathrm{\&rho;}}_h}{e}^{-k_2/T_f}dt---\left(4\right)$

$d_e=d_{ti}-2{\mathrm{\&delta;}}_h=d_{ti}-2{\&Integral;}_0^t\frac{{\mathrm{uk}}_1{\mathrm{\&Delta;T}}_{sub}}{{\mathrm{\&rho;}}_h}{e}^{-k_2/T_f}dt---\left(5\right)$

In formula, δ_hFor hydrate layer thickness；ρ_hFor hydrate density；d_tiFor test string original inner diameter.

7. judge the Hydrate Plugging order of severity in test string, determine the position that Hydrate Plugging occurs at first, calculate test Tubing string is by the completely plugged required time of hydrate；

8. according to the Hydrate Plugging order of severity in test string, determine early warning signal rank, make alarm send corresponding pre- Alert signal；According to test string by the order of severity of Hydrate Plugging, early warning signal is divided into four grades, if 0.7d_ti≤d_e< 0.9d_ti, then alarm sends one-level early warning signal；If 0.6d_ti≤d_e<0.7d_ti, then alarm sends two grades of early warning signals；If 0.4d_ti≤d_e<0.6d_ti, then alarm sends three grades of early warning signals；If d_e<0.4d_ti, then alarm sends level Four early warning signal；

9. according to Hydrate Plugging early warning signal rank in test string, hydrate inhibitor automatic injection system responds； If there is three grades or level Four early warning signal, then platform control system sends hydrate inhibitor injection instruction, starts hydrate and presses down Preparation injection pump, injects hydrate inhibitor in deep water gas well test string 101；

If the effective internal diameter of deep water gas well test string reduces the fastest position is positioned at the lower section of testing tree under water, then start the first water Compound inhibitors injection pump, injects hydrate in deep water gas well test string by the first hydrate inhibitor fill nipple and presses down Preparation；

If the effective internal diameter of test string reduces the fastest position is positioned at testing tree and the second hydrate inhibitor fill nipple under water Between, then start the second hydrate inhibitor injection pump, in deep water gas well test string, inject hydration by testing tree under water Thing inhibitor；

If the effective internal diameter of test string reduces the fastest position and is positioned at more than the second hydrate inhibitor fill nipple, then start the Trihydrate inhibitor injection pump, injects hydration by the second hydrate inhibitor fill nipple in deep water gas well test string Thing inhibitor.