【摘要】：近臨界區(qū)定義為油藏溫度Tr介于0.95～1.05倍流體體系臨界溫度Tc。B油藏屬于近臨界揮發(fā)性油藏,初期采用溶解氣驅(qū)衰竭式開發(fā)取得了較好的效果,但因地層斷裂和儲(chǔ)層砂體尖滅等地質(zhì)因素影響,各井控制區(qū)域間連通性差。目前,許多井區(qū)面臨地層能量不足、地層能量差異大、產(chǎn)量衰減快等問題,油田生產(chǎn)形勢嚴(yán)峻。此外,在油田實(shí)際生產(chǎn)過程中表現(xiàn)出"地層壓力較低時(shí)生產(chǎn)氣油比依然保持穩(wěn)定"、"井筒中流體壓力梯度倒置"等與常規(guī)溶解氣驅(qū)衰竭式開發(fā)理論動(dòng)態(tài)不一致、與井筒中流體重力分異相悖的異常生產(chǎn)特征。針對(duì)B油藏目前存在的生產(chǎn)問題及異常現(xiàn)象,本文通過流體PVT實(shí)驗(yàn)以落實(shí)油藏流體相態(tài)特征;根據(jù)油藏生屑云巖儲(chǔ)層實(shí)際地質(zhì)情況,剖析了油田生產(chǎn)動(dòng)態(tài)異常特征產(chǎn)生的原因;結(jié)合國內(nèi)外類似油田開發(fā)經(jīng)驗(yàn),根據(jù)不同驅(qū)替介質(zhì)實(shí)驗(yàn)結(jié)果和數(shù)值模擬結(jié)果,確定了后期改善油田開發(fā)效果的調(diào)整措施。本文完成了以下主要研究工作并取得了相應(yīng)的研究成果:(1)歸納總結(jié)了 B油田生屑云巖儲(chǔ)層地質(zhì)特征與油藏特征,歸納國內(nèi)外類似揮發(fā)性油田開發(fā)技術(shù)對(duì)策以及油藏開發(fā)規(guī)律,為開展B油田后續(xù)相關(guān)研究工作奠定了基礎(chǔ)。(2)完成流體常規(guī)PVT實(shí)驗(yàn),落實(shí)了油藏近臨界流體相態(tài)特征,明確了 B油田(Tc-T地=1℃)屬于近臨界高揮發(fā)性油藏。在壓力高于25MPa時(shí),油氣體系屬于界面張力低于1mN/m的低張力體系。(3)在對(duì)油田基本生產(chǎn)動(dòng)態(tài)特征進(jìn)行總結(jié)基礎(chǔ)上,結(jié)合近臨界流體特性及油藏生屑云巖儲(chǔ)層孔喉結(jié)構(gòu)特點(diǎn),剖析了生產(chǎn)氣油比異常穩(wěn)定與井筒流體壓力梯度倒置現(xiàn)象產(chǎn)生的原因和機(jī)理。(4)開展了不同介質(zhì)(水、地層氣、CO2或N2)驅(qū)替實(shí)驗(yàn),并根據(jù)實(shí)驗(yàn)結(jié)果優(yōu)選了油藏合理開發(fā)方式。(5)建立了揮發(fā)性油藏組分機(jī)理模型,論證了揮發(fā)性油藏不同開發(fā)方式(衰竭式、注水、注氣)下的原油采收率,并對(duì)油藏轉(zhuǎn)注時(shí)機(jī)進(jìn)行了優(yōu)化,得出注伴生氣是最經(jīng)濟(jì)可行的開發(fā)方式,且注氣時(shí)間越早,原油采收率越高。研究結(jié)果對(duì)油田后期開發(fā)調(diào)整有十分重要的指導(dǎo)意義。
[Abstract]:Near-critical zone is defined as reservoir temperature (Tr) of 0.95 ~ 1.05 times fluid system critical temperature Tc.B reservoir belongs to near-critical volatile reservoir. However, due to geological factors such as formation fault and reservoir sand body pinning, the connectivity between well control areas is poor. At present, many well areas are faced with problems such as insufficient formation energy, large difference of formation energy, fast production attenuation and so on. In addition, in the actual production process of oil field, "the ratio of producing gas to oil is still stable when the formation pressure is low", and the "inversion of fluid pressure gradient in wellbore" is inconsistent with the theory of conventional dissolved gas drive failure development. Abnormal production characteristics contrary to fluid gravity differentiation in wellbore. In view of the production problems and abnormal phenomena existing in reservoir B at present, this paper uses fluid PVT experiment to carry out reservoir fluid phase characteristics, analyzes the causes of abnormal characteristics of production performance in oil field according to the actual geological conditions of reservoir bioclastic dolomite reservoir. Combined with the development experience of similar oilfields at home and abroad, according to the experimental results of different displacement media and numerical simulation results, the adjustment measures to improve the oilfield development effect in the later stage are determined. This paper has completed the following main research work and obtained the corresponding research results: (1) summed up the geological characteristics and reservoir characteristics of bioclastic dolomite reservoirs in B oilfield, summarized the technical countermeasures and reservoir development laws of similar volatile oil fields at home and abroad. It lays a foundation for the subsequent research work in B oilfield. (2) the conventional PVT experiment of fluid is completed, the near critical fluid phase behavior of the reservoir is confirmed, and the near critical high volatility reservoir (Tc-T = 1 鈩，

本文編號(hào)：2285759