Stochastic modeling techniques have been widely applied to oil-gas reservoir lithofacies.Markov chain simulation~however~is still under development~mainly because of the difficulties in reasonably defining conditional...Stochastic modeling techniques have been widely applied to oil-gas reservoir lithofacies.Markov chain simulation~however~is still under development~mainly because of the difficulties in reasonably defining conditional probabilities for multi-dimensional Markov chains and determining transition probabilities for horizontal strike and dip directions.The aim of this work is to solve these problems.Firstly~the calculation formulae of conditional probabilities for multi-dimensional Markov chain models are proposed under the full independence and conditional independence assumptions.It is noted that multi-dimensional Markov models based on the conditional independence assumption are reasonable because these models avoid the small-class underestimation problem.Then~the methods for determining transition probabilities are given.The vertical transition probabilities are obtained by computing the transition frequencies from drilling data~while the horizontal transition probabilities are estimated by using well data and the elongation ratios according to Walther's law.Finally~these models are used to simulate the reservoir lithofacies distribution of Tahe oilfield in China.The results show that the conditional independence method performs better than the full independence counterpart in maintaining the true percentage composition and reproducing lithofacies spatial features.展开更多
Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectra...Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power （0-6 kW） of ICPs （inductively coupled plasmas）. With the increase of net input power, the intensity of Hα im- proves rapidly （0-2 kW）, and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes： obvious increase （0-2 kW）, rapid increase （2-4 kW）, almost constant （4-6 kW）; while the intensities of Hγ increase very slowly. The energy levels of the excited hydro- gen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results.展开更多
基金Project(2016YFB0503601)supported by the National Key Research and Development Program of ChinaProject(41730105)supported by the National Natural Science Foundation of China
文摘Stochastic modeling techniques have been widely applied to oil-gas reservoir lithofacies.Markov chain simulation~however~is still under development~mainly because of the difficulties in reasonably defining conditional probabilities for multi-dimensional Markov chains and determining transition probabilities for horizontal strike and dip directions.The aim of this work is to solve these problems.Firstly~the calculation formulae of conditional probabilities for multi-dimensional Markov chain models are proposed under the full independence and conditional independence assumptions.It is noted that multi-dimensional Markov models based on the conditional independence assumption are reasonable because these models avoid the small-class underestimation problem.Then~the methods for determining transition probabilities are given.The vertical transition probabilities are obtained by computing the transition frequencies from drilling data~while the horizontal transition probabilities are estimated by using well data and the elongation ratios according to Walther's law.Finally~these models are used to simulate the reservoir lithofacies distribution of Tahe oilfield in China.The results show that the conditional independence method performs better than the full independence counterpart in maintaining the true percentage composition and reproducing lithofacies spatial features.
基金supported by the National Magnetic Confinement Fusion Science Program of China(Nos.2011GB108011 and 2010GB103001)the Major International(Regional) Project Cooperation and Exchanges(No.11320101005)
文摘Hα（Balmer-alpha）, Hβ （Balmer-beta） and Hγ （Balmer-gamma） spectral line inten- sities in atomic hydrogen plasma are investigated by using a high-power RF source. The intensities of the Hα, Hβ and Hγ spectral lines are detected by increasing the input power （0-6 kW） of ICPs （inductively coupled plasmas）. With the increase of net input power, the intensity of Hα im- proves rapidly （0-2 kW）, and then reaches its dynamic equilibrium; the intensities of Hβ can be divided into three processes： obvious increase （0-2 kW）, rapid increase （2-4 kW）, almost constant （4-6 kW）; while the intensities of Hγ increase very slowly. The energy levels of the excited hydro- gen atoms and the splitting energy levels produced by an obvious Stark effect play an important role in the results.
