【摘要】：目前,水平井蒸汽吞吐是國內(nèi)外各油田開發(fā)稠油油藏的重要方法,但是在實際的油田開發(fā)過程中,水平井筒內(nèi)的流體存在一定的壓差,使得水平井筒內(nèi)的流體從趾端流向跟端,同時沿水平井筒生產(chǎn)方向也有流體不斷地從地層流入,這就是一種變質(zhì)量流動過程,而且井筒內(nèi)的流動和油藏滲流之間相互影響、相互作用。在水平井籠統(tǒng)采油過程中,水平井筒的兩端是存在一定壓力差的,在稀油井或含水較高的油井,沿水平井筒長度方向的壓力降通常都是很小的,基本可以忽略不計。但是對于高粘度長距離水平段的油井,水平井筒內(nèi)可能會產(chǎn)生較大的壓力降,這種壓降最終的結(jié)果可能是跟部生產(chǎn)壓降高于端部,使得流體不均勻地沿井眼流動,即使在均質(zhì)地層中,這種壓差(即根部-端部效應(yīng))也會存在,即油井根部動用較好,但是在生產(chǎn)一段時間后出現(xiàn)水錐或氣錐現(xiàn)象,最終導(dǎo)致油井的生產(chǎn)壽命過早結(jié)束,在油井水平段的端部留下大量的剩余油。為了實現(xiàn)水平井段油層的均勻泄油,本文提出了水平井分采同抽的方案,即在水平井的水平段中下入中心管,將中心管和水平段環(huán)形空間各自作為獨立的液流通道進行開采。但是,對于采取分抽方案后水平段壓降變化規(guī)律及其對油井流入動態(tài)的影響仍不明確。因此,有必要研究地層深處向井流動及水平井井筒內(nèi)的流動特性,為后續(xù)抽汲參數(shù)的優(yōu)化設(shè)計提供理論依據(jù)。本文首先從基本的質(zhì)量、動量和能量守恒方程出發(fā),以油水兩相流理論為依據(jù),充分考慮井壁摩擦、加速損失以及液流混合干擾等造成的壓降,建立了水平井井筒流動壓降計算的數(shù)學(xué)模型;同時以兩相滲流力學(xué)理論為基礎(chǔ),推導(dǎo)出了水平井在油藏中產(chǎn)生的勢,建立了水平井地層穩(wěn)定滲流方程,確定水平井井筒的流入動態(tài)模型;根據(jù)壓力的連續(xù)性、質(zhì)量體積平衡條件,并利用溫度的能量守恒方程把井筒模型和油藏模型連接起來建立耦合模型,并用VB語言編制了計算程序并導(dǎo)入到MATLAB軟件對壓降分布規(guī)律進行了描述。通過對比加中心管前后壓降的變化規(guī)律,優(yōu)化了中心管的最優(yōu)距離以及管徑等的參數(shù)。最終得到:若水平井筒長度為100m時,加中心管后其產(chǎn)量比未加中心管產(chǎn)量增加約0.8~1.05m3/d,中心管管徑4cm,下入長度118m為最優(yōu),能使增產(chǎn)效果達到最大,增產(chǎn)量約為2 m3/d。,并且選取杜84大-H1井進行抽汲參數(shù)的優(yōu)選。最終選擇管式泵中的整體泵筒,泵徑為70mm,泵的柱塞面積為38.48cm2,聯(lián)接油管外徑為88.9mm,聯(lián)接抽油桿螺紋直徑為30.163mm,通過查找抽油機技術(shù)規(guī)范,選擇抽油機型號為CYJY14-6-89HB。
[Abstract]:At present, horizontal well steam huff and puff is an important method to develop heavy oil reservoirs at home and abroad, but in the actual oil field development process, there is a certain pressure difference in the fluid in the horizontal wellbore, which makes the fluid in the horizontal wellbore flow from the toes to the following end, and at the same time, there is a continuous inflow of fluid from the formation along the production direction of the horizontal wellbore, which is a process of variable mass flow. Moreover, the flow in wellbore and reservoir seepage interact and interact with each other. In the general production process of horizontal wells, there is a certain pressure difference at both ends of the horizontal wellbore. In dilute wells or wells with high water cut, the pressure drop along the direction of horizontal wellbore length is usually very small, which can be ignored. However, for oil wells with high viscosity and long distance, there may be a large pressure drop in the horizontal wellbore. The final result of this pressure drop may be that the pressure drop of the heel production is higher than that of the end, so that the fluid flows inevenly along the wellbore, and even in the homogeneous formation, the pressure difference (that is, the root-end effect) exists, that is, the root of the oil well is used well, but the phenomenon of water cone or gas cone occurs after a period of production. Finally, the production life of the oil well ends prematurely, leaving a large amount of remaining oil at the end of the horizontal section of the well. In order to realize uniform oil discharge in horizontal well section, a scheme of horizontal well production and pumping is put forward in this paper, that is, the central pipe and horizontal annular space are exploited as independent liquid flow channels in the horizontal section of horizontal well. However, it is still unclear about the variation of pressure drop in the horizontal section and its influence on the inflow performance of the oil well after the pumping scheme is adopted. Therefore, it is necessary to study the flow characteristics from deep formation to well and in horizontal wellbore, so as to provide theoretical basis for the optimization design of swabbing parameters. In this paper, based on the basic conservation equations of mass, momentum and energy, based on the theory of oil-water two-phase flow, the pressure drop caused by wellbore friction, accelerated loss and mixed interference of liquid flow is fully considered, and the mathematical model for calculating the flow pressure drop of horizontal well wellbore is established. At the same time, based on the theory of two-phase seepage mechanics, the potential of horizontal well in reservoir is deduced, the stable seepage equation of horizontal well formation is established, and the inflow dynamic model of horizontal well bore is determined. According to the continuity of pressure and the condition of mass volume balance, the wellbore model and reservoir model are connected by the energy conservation equation of temperature to establish the coupling model, and the calculation program is compiled with VB language and introduced into MATLAB software to describe the distribution law of pressure drop. By comparing the variation law of pressure drop before and after adding the central tube, the parameters of the optimal distance and diameter of the central pipe are optimized. Finally, if the horizontal wellbore length is 100m, the output of the central tube is increased by about 0.8 脳 1.05m3 / d, the diameter of the central pipe is 4cm, and the down-entry length is 118m, which can maximize the increase of production and increase the production of about 2m3 鈮，

本文編號：2503885