煤层气储层密度测井环境校正方法研究

发布时间：2018-01-09 14:04

本文关键词：煤层气储层密度测井环境校正方法研究　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：煤层气作为一种非常规能源,其开发越来越受到人们的重视,煤层气密度测井在煤储层识别和划分、储层参数计算方面具有重要作用。但由于煤储层孔隙和割理较为发育、煤岩机械强度低,测井过程中扩径现象明显,导致密度测量值出现偏差。因此有必要针对煤储层条件对密度测井曲线进行校正,还原煤层气储层真实密度值。论文针对煤储层段扩径严重的问题,以密度测井基本原理为基础,通过蒙特卡罗数值模拟方法开展了包括密度测井仪器参数优化、井眼扩径模型建立、扩径密度值的正演模拟等问题的研究,并完成密度测井扩径校正图版的绘制。最后通过对研究区密度测井资料的扩径校正和标准化处理,验证校正方案的合理性,达到消除井眼环境等非地层因素对密度测井影响的目的。论文首先采用蒙特卡罗计算方法完成了双源距密度测井仪器的建模,通过对所获取γ能谱结果进行处理,实现密度测井仪器参数的优选。综合考虑探测光子数和探测深度,确定了仪器短、长源距分别为13、33cm;设置短、长源距Na I(TI)探测晶体尺寸分别为Φ1.0*1.8、Φ1.5*6.0cm以达到探测效率的最优化;划分了在淡水泥浆情况下近、远探测器的密度能窗范围0.27~0.43、0.20~0.37Me V,拟合得到探测计数率与地层密度转换关系。其次,在确定仪器结构基础上,本文采用MCNP软件模拟了煤层气储层不同程度的坍塌情况以探讨井径变化对密度测井仪器响应的影响,正演模拟计算了煤层扩径密度值,并以“脊肋线”形式描绘了0~16cm扩径条件下模拟仪器密度响应值与煤岩实验值的差异。计算结果表明,扩径情况下探测密度值偏小,随着井径的增大,正演密度值逐渐向井液密度值趋近。随后论文以长源距探测器密度响应值为基础计算得到不同扩径条件下的校正量,并绘制相对应煤储层密度的密度测井井径校正图版。最后,论文基于上述井径校正图版,利用Sino Log测井软件对研究区内18口井密度资料进行了井眼扩径校正,同时利用频率直方图法并完成了井间标准化处理。校正结果表明,采用上述方法校正后的密度资料有效地消除了井径和非环境因素影响,校正结果比较理想。
[Abstract]:As a kind of unconventional energy, coalbed methane (CBM) development has been paid more and more attention, and CBM density logging is recognized and classified in coal reservoir. The calculation of reservoir parameters plays an important role, but due to the development of pore and cleat of coal reservoir, the mechanical strength of coal and rock is low, and the phenomenon of diameter expansion is obvious during logging. Therefore, it is necessary to correct the density log curve to reduce the true density value of coalbed methane reservoir. Based on the basic principle of density logging, this paper studies the optimization of density logging tool parameters, the establishment of borehole expanding model and the forward modeling of expanding density value by Monte Carlo numerical simulation method. Finally, the rationality of the calibration scheme is verified by the expansion correction and standardized processing of density logging data in the study area. In order to eliminate the influence of non-formation factors such as borehole environment on density logging, the paper first completes the modeling of dual source distance density logging tool by Monte Carlo method. By processing the results of 纬 -ray spectrum obtained, the parameters of density logging tool are optimized. Considering the number of photons and the depth of detection, it is determined that the instrument is short and the long source distance is 13 ~ 33cm. The crystal size of short, long source distance na I I I is 1. 8, 桅 1. 5 and 6. 0 cm, respectively, in order to optimize the detection efficiency. In the case of fresh water mud, the density energy window range of the far detector is 0.270.43 / 0.200.200.37Me V, and the relationship between the detection counting rate and the formation density conversion is obtained. On the basis of determining the instrument structure, this paper simulates the collapse of coalbed methane reservoir in different degrees by using MCNP software to discuss the influence of the change of well diameter on the response of density logging tool. The difference between the density response value of the simulated instrument and the experimental value of coal rock under the condition of 0 ~ 16cm diameter expansion is described in the form of "ridge rib line". The calculation results show that. Under the condition of expanding diameter, the detection density value is small, with the increase of well diameter. The forward density value is gradually approaching to the well fluid density value. Then, based on the density response value of the long source distance detector, the correction quantities under different expanding diameter conditions are calculated. And draw the density of coal reservoir density log diameter correction chart. Finally, the paper is based on the above well diameter correction chart. Sino Log logging software was used to correct the density data of 18 wells in the study area, and the frequency histogram method was used to complete the cross-well standardization processing. The density data corrected by the above method can effectively eliminate the influence of well diameter and non-environmental factors, and the correction results are satisfactory.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13;P631.81

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