缝洞储集体双侧向测井响应的物理模拟及特征分析

The application of dual lateral log in fracture-cavernous reservoirs has facing many problems since the complex pore space of fracture-cavernous reservoirs gives ambiguous information for dual lateral log responses and lacks of physical simulation results for the complex geological models.. An innovate method for physical simulation of dual lateral log response in complex fracture-cavernous reservoirs will be conducted based on the problems proposed. Geological models and well logging equipment are scaled down to adapt the demand of physical simulation via numerical simulation. Properties of fracture and cavernous will be considered completely since the conveniences of our new ways for the construction of physical models. Dual lateral log equipment for physical simulation will be analyzed carefully to suit the need of experiments, with an aim to have the same effects of dual lateral log instrument used in well logging. . Dual lateral log responses will be recorded for single fracture, parallel fractures, fracture network system, single cavity and the combination of fracture-cavity systems. Parameters which affect the dual lateral log responses such as fracture(or cavity) resistivity, developing degree, angle and location will be investigated based on physical simulation data and numerical simulation results.. Controlling and influential factors of dual lateral log responses are expected to determine by our research. The changing characteristics of deep and shallow resistivity will be studied and extracted for some typical fracture-cavernous reservoirs, effectiveness and applicability of dual lateral log in evaluation of fracture-cavernous reservoirs is expected to obtain with the analysis above. We hope that this study can supply theoretical foundations and suggestions for formation evaluation of fracture-cavernous reservoirs using dual lateral log data.

针对缝洞储集体的双侧向测井响应规律复杂、影响因素繁多及前人物理模拟条件过于简单等问题开展复杂三维缝洞储集体的双侧向测井物理模拟研究。基于数值仿真和实验室条件确定物理模拟的尺度，进行双侧向测井实验仪的结构优化研制和缝洞储集体实验模型的构建。在缩小尺度的地质体模型和测井实验仪研制基础上，开展单条裂缝、平行裂缝、网状裂缝和单一洞穴、缝洞组合等模拟地层条件的双侧向测井模拟实验测量。将物理模拟与数值仿真相结合，全面考察缝洞储集合体特征如电阻率、宽度（直径）、倾角、位置及组合关系等对双侧向测井响应的影响，分析双侧向测井的主控因素，明确典型缝洞储集体的双侧向测井响应特征，探索双侧向测井在缝洞储集体评价中的有效性、适用性，为基于双侧向测井的缝洞储集体参数计算、储层识别与综合评价提供依据。

双侧向测井作为一种成熟的测井方法，由于其具有较强的电流聚焦能力和较大的探测范围，对井旁地质异常体较为敏感，在缝洞储集体评价中起着重要的作用。为研究缝洞储集体的双侧向测井响应规律，提升双侧向测井识别与评价缝洞储集体的有效性，在数值仿真的基础上开展缝洞储集体的双侧向测井物理模拟，研究双侧向测井响应特征与缝洞储集体特征的关系。基于快速三维有限元算法开展了双侧向测井的数值仿真。重点分析了裂缝型地层、过井眼轴对称洞穴型地层、井旁洞穴地层的双侧向测井响应特征，总结了不同裂缝产状、发育密度、倾角等条件下的深浅侧向电阻率差异，明确了裂缝发育特征与测井响应的对应关系。对于洞穴型地层，分别探索了不同洞穴充填性质、规模及发育位置的双侧向测井特征，对洞穴型的双侧向测井识别进行了深入研究。研制等比例缩小型的双侧向测井物理模拟系统，并开展了洞穴型储层的实验分析。首先对物理模型的设计基础进行研究，分析物理模型与实验原型的相似近似性特征，包括边界、空间、时间条件和几何尺度及电尺寸条件的相似性。开展实验模型的设计与制作及缩小比例双侧向测井仪器的设计与制造。缩小比例双侧向测井实验系统包括井下电极系、地面电路、示波器、计算机控制系统等，测前设计主要包括影响洞穴储层有效性的主要因素如充填物电阻率特征和充填程度的控制与实施。在自制的实验平台中开展了缝洞储层的双侧向测井物理模拟。首先对贴仪器测量的两组洞穴模型开展物理模拟，并与同样条件的数值模拟结果进行对比分析，验证了物理模拟的正确性。在此基础上针对性的开展了缝洞储层的双侧向测井物理模拟。分析了洞穴电阻率、发育规模，与井轴距离等因素对深浅侧向电阻率的影响，以及不同裂缝规模、不同裂缝倾角以及不同裂缝走向的对比实验。结合数值仿真得到了缝洞储层双侧向测井响应的一般规律，为认识缝洞储层的双侧向测井响应特征，以及基于双侧向测井的缝洞识别有效性奠定了基础。