Investigating Induction Log response in the presence of natural fractures
Investigating Induction Log response in the presence of natural fractures
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DOI：
10.1016/j.petrol.2016.05.023
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发表时间：
2016-09
影响因子：
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通讯作者：
F. Khoshbakht;M. R. Rasaie;A. Shekarifard
中科院分区：
文献类型：
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作者：
F. Khoshbakht;M. R. Rasaie;A. Shekarifard
电阻率测井是确定油气饱和度的主要测井技术之一。对这些测井的错误解释导致在确定产层和计算原地碳氢化合物方面存在代价高昂的风险。岩性、流体类型、结构、岩液相互作用、泥岩、各向异性、地层几何、井眼形状、泥浆侵入和天然裂缝(如果存在)都会干扰电阻率测井的读数。在这方面，本文的主要目的是更好地了解裂缝对感应测井的影响，并考虑实际数据集的结果。来自一个高度裂缝的储集层。我们使用商业软件模拟了在存在自然裂缝的情况下通用感应测井的响应。研究了裂缝长度、孔径、倾角、距井壁距离等不同裂缝特征对感应测井的影响，结果表明，裂缝的各种特征对感应测井的影响程度不同。其中，裂缝的导流能力是最具争议的问题。当裂缝导电率小于基质时，裂缝导电率对块体导电率影响不大，但当裂缝与基质导电率之比达到10-1000时，导电率增加到高于基质的实际导电率。在极高电导率裂缝中，当裂缝与基质电导率之比为10+3~10+6时，裂缝对块体电导率有不利影响，记录的电导率迅速下降到基质实际电导率以下。裂缝长度和裂缝开度对感应测井曲线的影响有一定的相似性。模型表明，裂缝倾角对感应测井响应影响不大。
Resistivity logging is one of the main types of logging techniques which is used to determine saturation of hydrocarbon. Wrong interpretation of these logs leads to costly risks in determination of pay zones and calculation of hydrocarbon in place. Lithology, fluid types, texture, rock-fluid interaction, shale, anisotropy, bed geometry, borehole shape, mud invasion, and natural fractures (if existed) disturb the reading of resistivity logs.In this regard, the main objectives of this paper is to better understand the effects of fractures on Induction Logs and considering the results in a real dataset. From a highly fractured reservoir. We used a commercial software to model the response of a generic Induction Log in the presence of natural fractures. The effects of different characteristics of fractures including length, aperture, inclination, and distance from borehole wall on the Induction Log were investigated.The present study showed that all characteristics of fractures influence the Induction Log measurements in different degrees. Among them, fracture's conductivity is the most controversial one. For less conductive fractures than matrix, the fracture conductivity has minor impact on the bulk conductivity; however, when fracture to matrix conductivity ratio reaches 10–1000, the bulk conductivity increases to above the actual conductivity of the matrix. In very high conductive fractures, when fracture to matrix conductivity ratio is 10+3 to 10+6, fractures have adverse impact on the bulk conductivity, and the recorded conductivity rapidly decreases below the actual conductivity of matrix. The effect of fracture length and aperture on the Induction Logs is somehow similar. The model showed that fracture inclination has minor impact on the Induction Log's response.