【摘要】：在水合物藏注熱開(kāi)采過(guò)程中,同時(shí)考慮分解區(qū)和水合物區(qū)的傳熱規(guī)律對(duì)于定量理解水合物分解過(guò)程中的傳熱以及熱開(kāi)采效率評(píng)價(jià)等有著重要的作用。因此,研究分解前緣的移動(dòng)規(guī)律是有必要的。本文利用CMG-STARS建立了天然氣水合物開(kāi)采數(shù)值模型,模型中考慮了水合物分解動(dòng)力學(xué),質(zhì)量守恒,能量守恒,熱傳導(dǎo)和熱對(duì)流。通過(guò)與室內(nèi)實(shí)驗(yàn)擬合得到模型關(guān)鍵參數(shù),將建立的數(shù)值模型與TOUGH-Fx,Mallik水合物藏開(kāi)采試驗(yàn)數(shù)據(jù)進(jìn)行擬合,擬合效果較好,驗(yàn)證了軟件的可靠性。研究結(jié)果表明:降壓產(chǎn)生的分解前緣移動(dòng)較慢,注熱產(chǎn)生的分解前緣移動(dòng)速度相對(duì)較快,熱對(duì)流起主導(dǎo)作用,熱傳導(dǎo)作用較弱。對(duì)影響分解前緣移動(dòng)的因素進(jìn)行分析,包括地質(zhì)因素和開(kāi)采因素。地質(zhì)因素中敏感性較強(qiáng)的因素為初始水合物飽和度,地層孔隙度,較弱的因素為地層絕對(duì)滲透率,巖石導(dǎo)熱系數(shù),高飽和度(Sh≥0.6)、高孔低飽和度的水合物藏不適合注熱水驅(qū)替;對(duì)開(kāi)采因素的分析表明,影響水合物藏分解前緣移動(dòng)的主要因素是生產(chǎn)井井底壓力以及注入熱水的溫度和時(shí)間,相同注熱量下注水速率對(duì)分解前緣移動(dòng)的影響較小。針對(duì)Mallik天然氣水合物藏特征,分別進(jìn)行了單井降壓開(kāi)采及兩口井降壓注熱聯(lián)合開(kāi)采。單獨(dú)降壓開(kāi)采中,射開(kāi)層位出現(xiàn)明顯的分解前緣;聯(lián)合開(kāi)采中,生產(chǎn)層位由上到下,分解前緣移動(dòng)距離逐漸增大;上部層系水合物藏初始水合物飽和度較低,地層絕對(duì)滲透率較大,同時(shí)能夠得到蓋層傳導(dǎo)的熱量,上部層系水合物分解情況較好,下部層系分解情況相對(duì)差一些。
[Abstract]:In the process of hydrate reservoir heat injection extraction, it is important to consider the heat transfer law of decomposition zone and hydrate region for the quantitative understanding of heat transfer in hydrate decomposition process and the evaluation of thermal recovery efficiency. Therefore, it is necessary to study the moving law of the leading edge of decomposition. In this paper, CMG-STARS is used to establish a numerical model of gas hydrate production, in which hydrate decomposition kinetics, mass conservation, energy conservation, heat conduction and thermal convection are considered. The key parameters of the model were obtained by fitting with the laboratory experiments. The numerical model was fitted with the TOUGH-Fx,Mallik hydrate reservoir mining test data. The fitting effect was good and the reliability of the software was verified. The results show that the decomposing front moving slowly, the thermal convection plays the leading role and the heat conduction is weak. The factors affecting the front movement of decomposition are analyzed, including geological factors and mining factors. Among geological factors, the most sensitive factors are initial hydrate saturation, formation porosity, and the weaker factors are formation absolute permeability, rock thermal conductivity and high saturation (Sh 鈮，

本文編號(hào)：2402024