论文部分内容阅读
川西须家河组致密砂岩储层经历了复杂沉积、成岩及构造演化过程,储层物性及含气性在纵横向上均具有较强的非均质性。加强致密储层含气饱和度(S_g)测井对比研究,对深入研究储层气水分布、寻找优质储层及井间含气性对比具有重要意义。基于常规及特殊测井资料,从电学及声学角度出发,分别基于Archie公式及三相Biot-type方程(TPE)对川西须家河组致密砂岩储层岩石含气饱和度进行精细测井解释。研究结果表明,当模型参数选取适当条件下,2种方法均可获得良好的评价效果;确定了电学Archie公式(及其修正公式)方法的Archie常数,可为同类研究提供参考,泥质含量对该方法评价效果具有一定影响。利用TPE对S_g进行测井解释时,通过自适应方法获取地层固结参数α值,发现α值与电阻率的对数值之间满足幂指数关系,利用该定量关系可以对地层α进行预测;TPE评价方法受泥质含量影响较小,但会受地层真实S_g的影响,当真实S_g低于60%时S_g预测效果较好,而高于此值时,预测结果略微偏低。由于高含气饱和度不是导致声波频散和衰减的主要原因,因此该现象与岩石自身因素,即基质矿物组成、内部颗粒微观接触型式及孔—裂隙结构等方面因素有关。基于以上认识,根据实际资料掌握程度,可以优选适当方法对非饱和致密砂岩储层S_g进行精细测井解释。
The tight sandstone reservoirs in the Xujiahe Formation in western Sichuan experienced complex sedimentation, diagenesis and tectonic evolution. The physical properties and gas-bearing properties of the reservoirs are highly heterogeneous in vertical and horizontal directions. Strengthening the comparison of gas saturation (S_g) logging in tight reservoirs is of great significance for studying the distribution of gas and water in reservoirs, looking for good reservoirs and comparing gas permeability between wells. Based on the conventional and special logging data, the gas saturation of the tight sandstone reservoirs in the Xujiahe Formation in western Sichuan Province was finely interpreted based on the Archie formula and the three-phase Biot-type equation (TPE), respectively. The results show that, when the model parameters are selected under appropriate conditions, the two methods can obtain a good evaluation effect; determine the Archie constant of the electrical Archie formula (and its correction formula) method can provide reference for similar studies, the argillaceous content of The method to evaluate the effect has a certain impact. When using the TPE to interpret the S_g log, the α value of the formation consolidation parameter is obtained through the adaptive method. It is found that the exponential relationship between the α value and the logarithm value of the resistivity satisfies the exponential relationship, and the α can be predicted by the quantitative relationship. The evaluation method is less influenced by the shale content, but it will be affected by the true S_g of the formation. When the real S_g is lower than 60%, the S_g prediction effect is better, but when it is higher than this value, the prediction result is slightly lower. Since high gas saturation is not the main reason causing dispersion and attenuation of sound waves, the phenomenon is related to the factors of rock itself, such as the composition of matrix minerals, the microscopic contact type of internal particles and the pore-fracture structure. Based on the above understanding, according to the degree of actual data grasping, S_g of unsaturated tight sandstone reservoirs can be finely interpreted by suitable methods.