【作者】 马灵伟；

【导师】 顾汉明； 杨勤勇；

【作者基本信息】 中国地质大学 ， 地球探测与信息技术， 2014， 博士

【摘要】 针对塔中顺南地区奥陶系目标储层埋藏深度大(>6500m),地质情况复杂,缝洞型储层地震波场特征识别困难,储层有效预测难度大等问题,本文从顺南地区三维地震资料出发,以钻井、测井及典型岩芯测试等资料作为约束条件,采用随机介质理论实现了对地下复杂碳酸盐岩不同尺度、不同角度缝洞体的精确刻画,利用非均匀介质波动方程正演模拟技术,从缝洞型储层自身因素(发育尺度、发育角度、发育密度及含不同流体等情况)变化以及采集、处理、成像和地表沙层吸收衰减等角度开展缝洞型储层波场特征影响因素研究,为缝洞型储层(地质)与地震响应(地球物理)之间关系建立打下基础。在此基础上建立塔中顺南地区奥陶系碳酸盐岩缝洞型储层地震响应识别模式,优选对缝洞型储层敏感的地震属性,降低缝洞型储层预测中的多解性问题,为该区不同层系内缝洞型储层反射特征的认识及有效预测提供一定依据。针对塔中顺南地区奥陶系缝洞型储层地震响应识别模式建立及有效储层预测,本文开展的主要内容及成果为：1)基于测井资料及典型岩芯测试结果完善塔中顺南地区奥陶系各层系缝洞型储层岩石物理参数变化规律,为缝洞型储层模型建立、弹性反演、流体识别及储层预测打下岩石物理基础。2)通过引入方向因子θ,给出一种新的矢量自相关函数表达式,使产生的随机介质具有一定的方向优势,采用阈值截取法,提出缝洞体分布的长半轴l、短半轴s,及局部发育密度P来构造不同形式的缝洞型随机介质模型,实现了对地下复杂碳酸盐岩不同尺度、不同角度缝洞体的精确刻画。3)完善了小尺度缝洞体地震可检测分辨率研究理论,给出不同情况下小尺度缝洞体宽度振幅因子变化曲线,从理论上探讨小尺度缝洞体地震可检测性问题。常规地震勘探偏移剖面上,厚度远小于1/4波长的缝洞体不仅能够被检测,而且当缝洞体界面反射系数r较大时,在地震剖面上能够形成较强的“串珠状”反射特征,小尺度缝洞体反射能量主要受界面反射系数r及激发子波主频f及缝洞体横向尺度影响,缝洞体厚度h对其反射能量的影响不大；偏移剖面能识别缝洞体的横向尺度极限为缝洞体所发育背景围岩中波长的四分之一,纵向尺度上能识别缝洞体的极限为缝洞体复合反射系数Rl≥Rs(Rs为背景反射系数)时所对应的厚度hdmin。；同时给出小尺度缝洞体纵、横向尺度计算方法,为实际地震资料中缝洞型储层发育规模计算提供了依据。4)从缝洞型储层自身因素(发育尺度、发育角度、发育密度及含不同流体等情况)变化以及采集、处理、成像和地表沙层吸收衰减等角度开展影响缝洞型储层波场特征因素研究,建立了缝洞型储层(地质)与地震响应(地球物理)之间的对应关系。5)分层系建立塔中顺南地区奥陶系缝洞型储层模型,开展实际资料缝洞型储层地震响应特征研究,建立塔中顺南地区奥陶系各层系缝洞型储层地震响应特征识别模式。6)基于地震识别模式优选出对缝洞型储层敏感地震属性具有更明确的地质含义,后期钻井揭示储层的地震波场特征与建立的地震识别模式吻合较好,完善了基于缝洞型储层建模、非均匀介质正演模拟、地震波场特征分析及敏感地震属性优选等研究缝洞型储层地震响应特征及储层预测的一整套技术序列,实现了对缝洞型储层的有效预测,优选出3个有利勘探目标区域。本论文的主要创新点体现在：1)通过引入方向因子θ,给出一种新的矢量自相关函数表达式,使产生的随机介质具有一定的方向优势,在此基础上提出缝洞体分布的长半轴l、短半轴s,及局部发育密度P来构造不同形式的缝洞型随机介质模型,实现对地下复杂碳酸盐岩不同尺度、不同角度缝洞体的精确刻画。2)较详细地从缝洞型储层自身因素(发育尺度、发育规模、发育密度及含不同流体等情况)变化以及采集、处理、成像和地表沙层吸收衰减等角度开展影响缝洞型储层波场特征的因素研究,建立缝洞型储层(地质)与地震响应(地球物理)之间的对应关系,从而指导实际无井约束情况下缝洞型储层地震波场特征认识及识别。3)针对塔中顺南地区奥陶系缝洞型储层,完善了基于缝洞型储层建模、非均匀介质正演模拟、地震波场特征分析及敏感地震属性优选等研究缝洞型储层地震响应特征及储层预测一整套技术序列,建立塔中顺南地区奥陶系各层系缝洞型储层地震波场特征及地震识别模式,后期钻井钻遇储层的地震波场特征与建立的地震识别模式吻合率高,取得较好效果。更多还原

【Abstract】 Deeply buried (more than6500m) and complicatedly structured, the Ordovician Carbonate reservoirs in Tazhong Shunnan area are difficult to recognize and characterize. In this paper, I first used stochastic medium to precisely describe fractured and porous reservoirs with muti-scale under the constraint of3-D seismic data, drilling data and logging data of this area. Then we studied the factors affecting seismic response patterns of porous reservoirs by forward modeling techniques based on non-homogeneous medium wave equation. In this process, we mainly considered features of porous reservoirs (e.g. the scale and density of fractures, the fluids contained, etc.), as well as the attenuation of sand layers on the surface. In the end, we optimized the attributes most sensitive to porous reservoirs, which can help to provide a foundation for effective recognition of reflection characteristics in different strata and to reduce multiple solutions for reservoir prediction.The main contents and results of this paper are carried out as follows:1) Rock physics research was conducted in target area to obtain related parameters for model construction, elastic inversion, fluid identification and reservoir prediction.2) A direction factor,θ was introduced to a new expression of vector autocorrelation function, which could provide the random medium certain advantages on direction. Then we finely described the fractured and porous reservoirs with their long axis,l, short axis, s, and density, P. These parameters were calculated by intercept method.3) The theory of detectable resolution of small-scale fractures was improved by studying the relationship between the fractures’width and the amplitude factors in different case. Results show that on migration profiles, the lateral recognizable limit is one fourth wavelength of the surrounding rocks, and when Rl≥Rs (R, is reflection coefficient of fractures and Rs is background reflection coefficient), the longitudinal recognizable limit is hmind. In addition, the method of calculating vertical and horizontal scale was given, which provided the basis for evaluating the size of vuggy reservoir in actual data.4) A correspondence between fractured reservoirs (geological) and seismic response (geophysics) was established based on the research of affecting factors including reservoirs’ characters (scale, angle, density and fluid), data acquisition, data process, image and attenuation of sand layers on the surface.5) The Ordovician fractured reservoir models in Tazhong Shunnan area were built in different strata. Meanwhile, seismic response patterns in this area were concluded based on the research to field data and theoretical data.6) Some attributes with a clear geological meaning and sensitive to vuggy reservoir were optimized. A complete set of technical sequence for reservoir prediction in Tazhong, Shunnan area was constructed including the process of vuggy reservoir modeling, forward modeling in inhomogeneous media, seismic wave field analysis, seismic attributes optimization, etc. Based on this technical work flow, the characteristics of seismic wave field and seismic response pattern were summarized several fixed patterns. These patterns were highly consistent with actual data collected in a later time. Further, three favorable exploration target area were selected thought this analysis, which represent that an effective prediction of fractured reservoir was achieved.The main innovations of this paper are detailed as follows:1) A new expression of vector autocorrelation function was derived by introducing direction factor,θ. This expression can help to more finely descript geological models of Ordovician fractured reservoir.2) A correspondence between fractured reservoirs (geological) and seismic response (geophysics) was established based on the research of affecting factors including reservoirs’ characters (scale, angle, density and fluid), data acquisition, data process, image and attenuation of sand layers on the surface, which could guide the understanding of actual vuggy reservoir characteristics when under no constraints from well data.3) A complete set of technical sequence for reservoir prediction in Tazhong, Shunnan area was constructed. Based on this technical work flow, the characteristics of seismic wave field and seismic response pattern were summarized several fixed patterns. These patterns were highly consistent with actual data collected in a later time.更多还原