【摘要】：針對低壓、低滲、低產(chǎn)及有水氣藏在開采中后期普遍存在的積液問題,亟需開展排水采氣工藝措施以維持氣井穩(wěn)定生產(chǎn)。速度管排水采氣工藝能降低井筒的臨界攜液氣流速,減少氣液間的滑脫損失,提高氣井帶液能力。該工藝具有施工簡單、一次性投入低、不壓井作業(yè)、對地層傷害小等優(yōu)勢,其應(yīng)用越來越廣泛。但大牛地氣田生產(chǎn)實(shí)際表明,部分氣井在安裝速度管生產(chǎn)后不久,就出現(xiàn)產(chǎn)氣量、產(chǎn)液量及油壓下降的情況。究其原因是對速度管氣井氣液兩相管流規(guī)律和攜液機(jī)理認(rèn)識不清,導(dǎo)致對速度管井筒壓降預(yù)測模型和連續(xù)攜液臨界氣流量模型的選擇不準(zhǔn)確,從而對速度管尺寸的選擇不合理,最終導(dǎo)致氣井的生產(chǎn)能力下降。為此,本文開展了速度管氣液兩相流壓降實(shí)驗(yàn)和連續(xù)攜液實(shí)驗(yàn),基于實(shí)驗(yàn)數(shù)據(jù),建立了符合速度管流動(dòng)規(guī)律的壓降模型和連續(xù)攜液氣流量計(jì)算公式。主要工作如下： (1)根據(jù)大牛地氣田速度管排水采氣井常用的生產(chǎn)管柱尺寸(Φ38.1、Φ50.8mm以及環(huán)空φ38mm+φ76mm),選定了相對應(yīng)的三種管徑尺寸(φ40mm、φ、50mm以及環(huán)空φ40mm+φ80mm),設(shè)計(jì)制作了速度管排水采氣物理模擬實(shí)驗(yàn)裝置。實(shí)驗(yàn)管路總長8m,可調(diào)角度00-90°,可用于模擬速度管排水采氣井不同井段氣液兩相流動(dòng)。 (2)開展了管徑為40、50mm以及小環(huán)空內(nèi)的氣液兩相流動(dòng)實(shí)驗(yàn),利用數(shù)碼相機(jī)拍攝了不同流動(dòng)條件下的流型,并分析了流型變化與壓降之間的內(nèi)在關(guān)系。測試了液流速為1-10m3/d、氣流速為2-34m/s、傾斜角為15°-77°條件下速度管及小環(huán)空內(nèi)的壓降,并分析了這三種因素對壓降的影響規(guī)律。實(shí)驗(yàn)測試的壓降為速度管壓降模型的推導(dǎo)提供了數(shù)據(jù)支撐。 (3)基于實(shí)驗(yàn)數(shù)據(jù),在低液量(1-10m3/d)范圍內(nèi),對HagedomBrown模型進(jìn)行修正,建立了適用于速度管氣液兩相流規(guī)律的壓降模型。利用大牛地氣田34口速度管氣井的流壓測試數(shù)據(jù),對包括修正的HagedornBrown模型在內(nèi)的8個(gè)模型進(jìn)行了評價(jià),評價(jià)結(jié)果表明,修正模型的誤差最小,為大牛地氣田速度管氣井井筒壓降的計(jì)算提供了方法。 (4)開展了速度管及小環(huán)空中的連續(xù)攜液實(shí)驗(yàn),分析了液流速、傾斜角對連續(xù)攜液臨界氣流速的影響規(guī)律；同時(shí),利用數(shù)碼相機(jī),捕捉連續(xù)攜液狀態(tài)下的流型,揭示了連續(xù)攜液發(fā)生時(shí)的流型條件。 (5)基于實(shí)驗(yàn)數(shù)據(jù),考慮管徑、傾斜角、液流量的影響,對Belfroid攜液模型的相關(guān)系數(shù)進(jìn)行修正,建立了綜合的攜液修正模型,并利用大牛地氣田18口速度管氣井的測試數(shù)據(jù)對其進(jìn)行驗(yàn)證,準(zhǔn)確率為88.9%。 本文建立的速度管壓降模型和連續(xù)攜液氣流量模型為大牛地氣田速度管排水采氣工藝的參數(shù)優(yōu)化設(shè)計(jì)和攜液動(dòng)態(tài)預(yù)測提供了方法。
[Abstract]:In view of the problems of low pressure, low permeability, low production and liquid accumulation in the middle and late stage of exploitation, it is urgent to carry out drainage gas production technology measures to maintain the stable production of gas wells. The drainage gas production technology of velocity pipe can reduce the critical liquid carrying gas velocity of wellbore, reduce the slippage loss between gas and liquid, and improve the fluid carrying capacity of gas well. This technology has the advantages of simple construction, low one-time input, no killing operation and less damage to formation, so it is more and more widely used. However, the production practice of Daniudi gas field shows that the gas production, liquid production and oil pressure of some gas wells decrease shortly after the installation of speed tube production. The reason is that the law of gas-liquid two-phase pipe flow and the mechanism of carrying liquid in velocity tube gas well are not clearly understood, which leads to the inaccurate selection of velocity pipe wellbore pressure drop prediction model and continuous liquid carrying critical gas flow model, thus unreasonable selection of velocity tube size, and finally leads to the decrease of gas well production capacity. For this reason, the pressure drop experiment and continuous liquid carrying experiment of gas-liquid two-phase flow in velocity tube are carried out in this paper. based on the experimental data, the pressure drop model and the calculation formula of continuous liquid carrying gas flow rate in accordance with the flow law of velocity tube are established. The main work is as follows: (1) according to the production string dimensions (桅 38.1, 桅 50.8mm and annular 蠁 38mm 蠁 76mm) commonly used in velocity pipe drainage gas production wells in Daniudi gas field, three corresponding pipe diameters (蠁 40mm, 蠁, 50mm and annular 蠁 40mm 蠁 80mm) are selected, and the physical simulation experimental devices of velocity pipe drainage gas production are designed and manufactured. The total length of the experimental pipeline is 8 m and the adjustable angle is 00 擄90 擄. It can be used to simulate the gas-liquid two-phase flow in different well sections of velocity pipe drainage gas wells. (2) the experiments of gas-liquid two-phase flow in 40, 50mm and small annulus were carried out. The flow patterns under different flow conditions were photographed by digital camera, and the internal relationship between the change of flow pattern and pressure drop was analyzed. The pressure drop in the velocity tube and small annulus was measured when the liquid flow rate was 1 鈮，

本文編號：2508710