本文選題：蒙特卡洛 + 商分辨率　； 參考：《浙江大學》2015年碩士論文

【摘要】：本文基于放射性測井中經(jīng)常使用的蒙特卡洛方法,采用蒙卡模擬軟件MCNP,建立補償中子測井模型,通過大量粒子的模擬計算,研究了縱向分辨率與源距的響應關(guān)系；不同近、遠源距組合下對探測器計數(shù)率,計數(shù)比,孔隙度靈敏度等影響情況；不同探測器尺寸對計數(shù)率,計數(shù)率比值及孔隙度靈敏度的影響；不同屏蔽材料的屏蔽效果。確定了中子測井縱向分辨率與源距成線性關(guān)系,對于采用雙源距比值求取孔隙度的補償中子測井來說,縱向分辨率主要取決于長源距,大小基本與長源距的長度基本一致。高分辨率中子探測器結(jié)構(gòu)的設計主要考慮了計數(shù)率,縱向分辨率和孔隙度靈敏度等因素,長源距應盡量短,長短源距間隔應盡可能大,結(jié)合工程實際,確定合適的源距,探測器尺寸。分析了對中子測井孔隙度產(chǎn)生影響的各個因素,然后利用數(shù)值模擬的方法對井眼環(huán)境的影響進行了校正,包括井徑,泥餅,井眼間隙,挖掘效應,巖性校正和泥漿礦化度校正,對各個影響因素做出了校正圖版。經(jīng)過現(xiàn)場實驗驗證,儀器重復性一致性良好,與傳統(tǒng)補償中子儀器的分辨率只有0.6米左右相比,縱向分辨率得到明顯提高,分層能力更強。
[Abstract]:Based on Monte Carlo method often used in radioactive logging, this paper uses Monte Carlo simulation software MCNP to establish a compensated neutron log model. Through the simulation of a large number of particles, the response relationship between the longitudinal resolution and the source distance is studied, and the influence of the counting rate, the count ratio and the porosity sensitivity under the combination of different near and far source distance is influenced. The influence of the size of the detector on the counting rate, the ratio of counting rate and the sensitivity of porosity, the shielding effect of different shielding materials, the linear relation between the longitudinal resolution and the source distance of the neutron log is determined, and the compensation neutron log which uses the ratio of the double source distance to the porosity is determined mainly by the long source distance and the size. The design of the structure of high resolution neutron detector mainly considers the counting rate, the longitudinal resolution and the porosity sensitivity. The long source distance should be as short as possible and the distance between the long and short source distance should be as large as possible. In combination with the engineering practice, the appropriate source distance and the detector size are determined. The porosity of the neutron log is analyzed. The influence of the borehole environment is corrected by numerical simulation, including well diameter, mud cake, hole clearance, excavation effect, lithology correction and mud mineralization correction. The correction chart is made for each influence factor. After field experiments, the repeatability of the instrument is good and the traditional compensation is well compensated. The resolution of the neutron instrument is only about 0.6 meters, and the vertical resolution is obviously improved and the stratification ability is stronger.
【學位授予單位】：浙江大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P631.817

【參考文獻】

相關(guān)期刊論文 前1條

1 蔡曉波;申會堂;;蒙特卡羅方法、核模擬程序MCNP及MCNP在核測井中的應用[J];艦船科學技術(shù);2003年S1期

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本文編號：1928518