本文關(guān)鍵詞： 煤層氣 鉆屑 撈砂 水平井 啟動流量 壓差 流型　出處：《西安科技大學》2017年碩士論文　論文類型：學位論文

【摘要】：煤層具有低抗拉強度、抗壓強度、彈性模量和高泊松比的特性。煤層氣井在鉆井、排采過程中由于壓力波動、氣液沖刷、機械碰撞等外力作用,不可避免地會產(chǎn)生煤粉,煤粉產(chǎn)出對煤層氣的排采有有利的一面,適量的煤粉排出,可以疏通流體運移通道,有利于煤層流體導(dǎo)通,擴大壓降范圍,增大煤層氣井的控氣面積,提高煤層氣井的產(chǎn)氣量。但是當煤粉產(chǎn)出量過大時,就會產(chǎn)生不利的影響。一方面,壓力波動或者排水強度過大會導(dǎo)致煤粉激動,煤粉隨液相或者氣相一起運移。當流速降低或者遇到狹窄不能通過的縫隙,煤粉便沉降淤積在該處,會降低原始裂隙和支撐裂隙的導(dǎo)通能力,導(dǎo)致儲層滲透性下降。另一方面,由于水平井在鉆進時是略有起伏式的,和液相一同進入水平井段的煤粉,當運移至上行井段,若液相流速不足以搬運抬升煤粉,煤粉便逐漸淤積在井筒中。造成不同程度的阻塞井筒,有可能造成水平井報廢。運移至排水泵位置的煤粉,可能會導(dǎo)致埋泵現(xiàn)象。煤粉堵塞泵吸入口,致使閥門關(guān)閉不嚴,大幅度降低水泵功效。有時會形成黏稠膠狀物進入泵內(nèi),對泵筒和柱塞造成磨損,泵效降低,甚至造成卡泵現(xiàn)象,導(dǎo)致排采過程中頻繁檢泵。為此,有必要確定煤粉啟動的條件和規(guī)律,為控制排采速度提供依據(jù),進而防止發(fā)生埋泵,卡泵等排采事故,延長檢泵周期。通過實驗?zāi)M鉆屑樣和撈砂樣在水平井中的運動得到如下認識:不同粒徑的鉆屑煤粉的啟動運移規(guī)律基本相同。相對而言撈砂樣的運移規(guī)律更為復(fù)雜。但是這兩種煤樣隨著液相流量的增加,遵循靜止-滑動-滾動-層移-懸移的運移狀態(tài)變化規(guī)律。與鉆屑樣相比,粒徑較小時,撈砂樣運移需要的流量值較小,這是由于撈砂樣磨圓度好,易于滾動。粒徑較大時,由于撈砂樣中的沙粒密度大,鉆屑樣相對更好啟動。改變模擬管道的傾角,則啟動流量也會發(fā)生相應(yīng)的變化。隨著管道下傾加劇,煤粉啟動流量變小,傾角越大,啟動越困難。在確定的管道傾斜角度下,隨著粒徑增大,煤粉的啟動流量增加。用一次函數(shù)對啟動流量和煤粉粒徑之間的關(guān)系進行擬合,擬合度較高。一次函數(shù)對啟動流量和傾角間關(guān)系的擬合度也很好,這說明通過一次函數(shù)可以較好的預(yù)測不同粒徑和管道傾角下的煤粉啟動流量。氣相加入后,管道中為三相介質(zhì)相互作用狀態(tài),氣相對水流的擾動作用很強,煤粉很容易就懸浮起來隨水流開始運移。管道一旦有角度,氣液比越大,氣相的擾動作用就越強,煤粉的運移效率隨之增加。管道的流量與壓差直接相關(guān),壓差越大流量越大,兩者關(guān)系用一次函數(shù)擬合度高。研究的最后建立了液固兩相流、氣液固三相流煤粉啟動-運移模型,可大概預(yù)測不同粒徑煤粉在特定水平井傾角下的啟動流量,以及不同氣液比對應(yīng)的壓差。
[Abstract]:Coal seam has the characteristics of low tensile strength, compressive strength, elastic modulus and high Poisson ratio. Coal powder will inevitably be produced in coalbed methane wells due to pressure fluctuation, gas-liquid scour, mechanical collision and other external forces. The output of pulverized coal has a beneficial effect on coal bed methane production. Proper amount of pulverized coal can dredge the passage of fluid transfer, which is beneficial to the flow conduction of coal seam, the expansion of pressure drop range, and the increase of gas control area of coalbed methane wells. Increase the gas production of coalbed methane wells. But when the production of pulverized coal is too large, there will be adverse effects. On the one hand, pressure fluctuations or excessive drainage intensity will lead to pulverized coal agitation. Pulverized coal moves along with liquid or gas phase. When the flow rate decreases or the narrow gap cannot pass, the pulverized coal settles and silts there, which reduces the conductivity of the original fracture and the supporting fissure, and results in the decrease of reservoir permeability, on the other hand, Because the horizontal well is slightly undulating during drilling, the pulverized coal that enters the horizontal well with the liquid phase, when transported to the upstream section, if the liquid flow velocity is not sufficient to carry the raised pulverized coal, The pulverized coal gradually silts up in the wellbore, causing various degrees of blockage in the wellbore, which may cause the horizontal well to be abandoned. The pulverized coal transported to the position of the drainage pump may lead to the phenomenon of burying the pump. The pulverized coal will block the suction port of the pump and cause the valve to close insufficiently. Reduce pump efficiency by a large margin. Sometimes a viscous glue will enter the pump, causing wear and tear to the pump cylinder and plunger, reducing pump efficiency and even causing pump jam phenomenon, leading to frequent pump inspection in the process of discharging and mining. For this reason, It is necessary to determine the conditions and rules of pulverized coal starting, to provide the basis for controlling the drainage speed, and to prevent the occurrence of mining accidents, such as burying pump and stuck pump, etc. Through the experimental simulation of the movement of cuttings and sand samples in horizontal wells, we can get the following understanding: the starting and migration laws of different diameter cuttings drilling coal powder are basically the same, and relatively speaking, the migration laws of dredged sand samples are more regular. But these two kinds of coal samples increase with the liquid flow rate, It follows the law of movement state variation of static, sliding, rolling, layer moving and suspended moving. Compared with the sample of drilling debris, the flow rate of the sand sample is smaller than that of the sample of drilling. This is due to the fact that the sand sample has good grinding roundness, is easy to roll, and when the particle size is larger, Because the sand density in the dredged sand sample is high, the drilling sample is better to start up. If the inclination angle of the simulated pipeline is changed, the starting flow rate will change accordingly. With the downdip of the pipeline increasing, the starting flow rate of pulverized coal becomes smaller and the inclination angle is larger. The more difficult it is to start, the more difficult the starting flow rate of pulverized coal increases with the increase of particle size under the fixed inclined angle of the pipeline. The relationship between the starting flow rate and the particle size of pulverized coal is fitted by the first function. The first function has a good fit for the relationship between the starting flow rate and the inclination angle, which indicates that the starting flow rate of pulverized coal under different particle size and pipe inclination angle can be well predicted by the first order function. In a three-phase medium interaction state, the disturbance between gas and water flow is very strong, and pulverized coal is easily suspended to start moving with the water flow. Once the pipe has an angle, the greater the gas-liquid ratio, the stronger the disturbance of the gas phase. The flow rate of pipeline is directly related to the pressure difference, the greater the pressure difference is, the greater the flow rate is, the higher the fitting degree is with the primary function. Finally, the liquid-solid two-phase flow is established. The gas-liquid-solid three-phase pulverized coal starting-migration model can be used to predict the starting flow rate and the pressure difference of different gas-liquid ratio under certain horizontal well inclination angle.
【學位授予單位】：西安科技大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TD712

【參考文獻】

相關(guān)期刊論文 前10條

1 劉春花;劉新福;周超;;煤層氣井排采過程中煤粉運移規(guī)律研究[J];煤田地質(zhì)與勘探;2015年05期

2 胡秋嘉;唐鈺童;吳定泉;劉春春;閆玲;張武昌;;氮氣泡沫解堵技術(shù)在樊莊區(qū)塊多分支水平井上的應(yīng)用[J];中國煤層氣;2015年05期

3 鄭春峰;李昂;程心平;趙景輝;;煤層氣有桿泵井排采煤粉產(chǎn)出規(guī)律表征與分析[J];科學技術(shù)與工程;2015年28期

4 姚征;曹代勇;熊先鉞;魏迎春;王孝亮;張傲翔;;基于示功圖監(jiān)測的煤粉相關(guān)井下故障預(yù)警[J];煤炭學報;2015年07期

5 張芬娜;陳波;李明忠;綦耀光;孟尚志;;煤粉顆粒在垂直井筒沉降規(guī)律試驗研究[J];石油機械;2015年06期

6 羅莉濤;劉衛(wèi)東;姜偉;管保山;胡新海;叢蘇男;;煤粉懸浮劑性能評價及現(xiàn)場實施方案設(shè)計與應(yīng)用[J];鉆井液與完井液;2015年03期

7 張芬娜;李明忠;綦耀光;朱洪迎;孟尚志;;煤層氣排采產(chǎn)氣通道適度攜煤粉理論[J];中國石油大學學報(自然科學版);2015年02期

8 楊宇;曹煜;田慧君;李東;張昊;孫晗森;吳翔;陳萬鋼;;壓裂中煤粉對煤儲層損害機理分析與防控對策[J];煤炭科學技術(shù);2015年02期

9 李小明;曹代勇;姚征;王孝亮;魏迎春;向曉蕊;;基于流態(tài)物理模擬試驗的煤粉排出機理研究[J];煤炭科學技術(shù);2015年02期

10 楊延輝;湯達禎;楊艷磊;陳龍偉;陶樹;;煤儲層速敏效應(yīng)對煤粉產(chǎn)出規(guī)律及產(chǎn)能的影響[J];煤炭科學技術(shù);2015年02期

相關(guān)會議論文 前2條

1 付裕;劉升貴;張晶;涂坤;邵陽;劉金梅;;煤層裂縫粗糙性對煤粉運移沉積的影響[A];北京力學會第21屆學術(shù)年會暨北京振動工程學會第22屆學術(shù)年會論文集[C];2015年

2 王慶偉;陳春琳;張元元;姚征;;煤層氣鉆井過程中應(yīng)力集中作用下煤粉產(chǎn)出力學機理分析[A];2013年煤層氣學術(shù)研討會論文集[C];2013年

，

本文編號：1502394