多孔介質(zhì)壓敏效應(yīng)對(duì)孔隙結(jié)構(gòu)和滲流能力的影響研究
發(fā)布時(shí)間：2018-11-14 12:46
【摘要】：目前已有大量的宏觀實(shí)驗(yàn)進(jìn)行多孔介質(zhì)中壓敏效應(yīng)的研究,但是壓敏效應(yīng)的微觀機(jī)制仍較缺乏。多孔介質(zhì)的孔喉結(jié)構(gòu)復(fù)雜,尤其是致密砂巖等非常規(guī)儲(chǔ)層,壓敏效應(yīng)會(huì)導(dǎo)致相應(yīng)的孔喉結(jié)構(gòu)發(fā)生大幅度變化,因此對(duì)孔隙級(jí)多孔介質(zhì)的壓敏效應(yīng)進(jìn)行系統(tǒng)的研究有重要意義。本文基于可以真實(shí)描述巖石內(nèi)部結(jié)構(gòu)特征的CT掃描技術(shù),結(jié)合數(shù)字巖心和孔隙網(wǎng)絡(luò)模型理論進(jìn)行分析,獲得有效應(yīng)力變化與孔隙結(jié)構(gòu)的變化關(guān)系;同時(shí),建立了孔隙尺度上滲流場(chǎng)-應(yīng)力場(chǎng)的流固耦合模型。在實(shí)驗(yàn)方面,首先,本文建立了基于CT掃描法構(gòu)建數(shù)字巖心的理論與方法。CT掃描獲得巖心的三維圖像,經(jīng)過濾波、二值分割處理得到數(shù)字巖心,提取孔隙網(wǎng)絡(luò)模型,分析巖心的幾何結(jié)構(gòu)特征和拓?fù)浣Y(jié)構(gòu)特征,并進(jìn)行流動(dòng)模擬獲得絕對(duì)滲透率等參數(shù)。然后,基于人造砂巖形成了一套基于CT掃描的應(yīng)力敏感實(shí)驗(yàn)及分析方法。根據(jù)行業(yè)標(biāo)準(zhǔn),在碳纖維巖心夾持器中進(jìn)行應(yīng)力敏感實(shí)驗(yàn),在不同壓力下對(duì)巖心進(jìn)行CT掃描,構(gòu)建不同應(yīng)力下的數(shù)字巖心,進(jìn)而提取不同應(yīng)力下的孔隙網(wǎng)絡(luò)模型,研究相應(yīng)的孔隙結(jié)構(gòu)特征和滲流規(guī)律。最后,將該套方法應(yīng)用到實(shí)際油田的中高滲砂巖和致密砂巖,進(jìn)行不同類型砂巖的應(yīng)力敏感實(shí)驗(yàn),并對(duì)兩種砂巖的應(yīng)力敏感進(jìn)行對(duì)比分析。在模擬方面,基于不可壓縮的N-S方程和Biot應(yīng)力應(yīng)變方程,構(gòu)建了孔隙尺度上流固耦合數(shù)學(xué)模型,利用有限元方法進(jìn)行了二維孔隙級(jí)流體流動(dòng)計(jì)算,物理模型選用二維規(guī)則圓模型、二維不規(guī)則圓模型和實(shí)際SEM圖像模型,得到了滲透率和孔隙度隨圍壓以及流動(dòng)壓差的變化規(guī)律。通過本文研究,形成了較為完整的基于CT實(shí)驗(yàn)的應(yīng)力敏感評(píng)價(jià)方法,對(duì)油氣田開發(fā)提高采收率具有重要應(yīng)用價(jià)值。
[Abstract]:At present, a large number of macroscopic experiments have been carried out to study the pressure-sensitive effect in porous media, but the microscopic mechanism of the pressure-sensitive effect is still lacking. The pore throat structure of porous media is complex, especially in unconventional reservoirs such as tight sandstone, the pressure sensitivity effect will lead to the corresponding pore throat structure change greatly, so it is of great significance to systematically study the pressure sensitivity effect of porous media. Based on the CT scanning technique which can describe the internal structure of rock, the relationship between the effective stress change and the pore structure is obtained by combining the theory of digital core and pore network model. At the same time, the fluid-solid coupling model of percolation field and stress field on pore scale is established. In the aspect of experiment, firstly, the theory and method of constructing digital core based on CT scanning method are established. Three dimensional image of core is obtained by CT scan, digital core is obtained by filtering and binary segmentation, and pore network model is extracted. The geometric and topological characteristics of the core are analyzed, and the parameters such as absolute permeability are obtained by flow simulation. Then, a set of stress-sensitivity experiments and analysis methods based on CT scanning are developed based on artificial sandstone. According to the industry standard, stress sensitivity experiments were carried out in carbon fiber core gripper, and the core was scanned by CT under different pressures to construct digital core under different stress, and then the pore network model under different stress was extracted. The pore structure characteristics and percolation law are studied. Finally, the method is applied to the medium and high permeability sandstone and tight sandstone in actual oilfield, and the stress-sensitivity experiments of different types of sandstone are carried out, and the stress sensitivity of the two types of sandstone is compared and analyzed. In the aspect of simulation, based on the incompressible N-S equation and Biot stress-strain equation, the fluid-solid coupling mathematical model on pore scale is constructed, and the two-dimensional porous fluid flow is calculated by finite element method. The physical model consists of two dimensional regular circle model, two dimensional irregular circle model and actual SEM image model. The variation of permeability and porosity with confining pressure and flow pressure difference is obtained. Through the research in this paper, a relatively complete stress-sensitive evaluation method based on CT experiment has been developed, which has important application value in oil and gas field development and improving oil and gas recovery.
【學(xué)位授予單位】：中國石油大學(xué)(華東)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE312
本文編號(hào)：2331198
[Abstract]:At present, a large number of macroscopic experiments have been carried out to study the pressure-sensitive effect in porous media, but the microscopic mechanism of the pressure-sensitive effect is still lacking. The pore throat structure of porous media is complex, especially in unconventional reservoirs such as tight sandstone, the pressure sensitivity effect will lead to the corresponding pore throat structure change greatly, so it is of great significance to systematically study the pressure sensitivity effect of porous media. Based on the CT scanning technique which can describe the internal structure of rock, the relationship between the effective stress change and the pore structure is obtained by combining the theory of digital core and pore network model. At the same time, the fluid-solid coupling model of percolation field and stress field on pore scale is established. In the aspect of experiment, firstly, the theory and method of constructing digital core based on CT scanning method are established. Three dimensional image of core is obtained by CT scan, digital core is obtained by filtering and binary segmentation, and pore network model is extracted. The geometric and topological characteristics of the core are analyzed, and the parameters such as absolute permeability are obtained by flow simulation. Then, a set of stress-sensitivity experiments and analysis methods based on CT scanning are developed based on artificial sandstone. According to the industry standard, stress sensitivity experiments were carried out in carbon fiber core gripper, and the core was scanned by CT under different pressures to construct digital core under different stress, and then the pore network model under different stress was extracted. The pore structure characteristics and percolation law are studied. Finally, the method is applied to the medium and high permeability sandstone and tight sandstone in actual oilfield, and the stress-sensitivity experiments of different types of sandstone are carried out, and the stress sensitivity of the two types of sandstone is compared and analyzed. In the aspect of simulation, based on the incompressible N-S equation and Biot stress-strain equation, the fluid-solid coupling mathematical model on pore scale is constructed, and the two-dimensional porous fluid flow is calculated by finite element method. The physical model consists of two dimensional regular circle model, two dimensional irregular circle model and actual SEM image model. The variation of permeability and porosity with confining pressure and flow pressure difference is obtained. Through the research in this paper, a relatively complete stress-sensitive evaluation method based on CT experiment has been developed, which has important application value in oil and gas field development and improving oil and gas recovery.
【學(xué)位授予單位】：中國石油大學(xué)(華東)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE312
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 王晨晨;姚軍;楊永飛;王鑫;;基于CT掃描法構(gòu)建數(shù)字巖心的分辨率選取研究[J];科學(xué)技術(shù)與工程;2013年04期
2 戴金星;倪云燕;吳小奇;;中國致密砂巖氣及在勘探開發(fā)上的重要意義[J];石油勘探與開發(fā);2012年03期
，本文編號(hào)：2331198
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