毛管数实验曲线再研究

在深入研究复合驱油技术过程中发现复合驱油过程中存在两种不同驱动状况：随着毛管数的增大驱油效果改善，而当毛管数达到一极限值后再继续增大，出现水相流速加快驱油效果变差情况，从经典毛管数与残余油饱和度关系实验曲线出发是不能解释的，由此提出对毛管数实验曲线的重新研究。通过驱油实验得到了新的“毛管数与残余油关系实验曲线QL”，并测得了残余油不再降低的极限毛管数、驱动状况转化的极限毛管数和对应于“第一类”驱动状况下的最低残余油饱和度值；同时通过类似的驱油实验进行了考核，结果表明实验所得的毛管数曲线正确地反映了复合驱油过程中毛管数与残余油饱和度之间的对应关系。因此，新的“毛管数与残余油关系实验曲线QL”将为今后复合驱技术研究和应用提供参考和依据。

复合驱相渗透率曲线再研究

在“毛管数与残余油饱和度关系实验曲线QL”研究基础上，对复合驱的相渗透率曲线进行了研究。毛管数曲线QL是在数值模拟研究发现两种不同驱动状况的基础上深入研究得出的，数值模拟研究结果能够被驱油实验证实，表明模拟计算软件对于复合驱相渗透率的描述是相对正确的。以毛管数与残余油关系实验曲线QL为基础，借鉴软件UTCHEM相渗透率曲线的数学描述，以驱油实验相配合，研究提出了以毛管数值为变量复合驱相渗透率曲线的描述式，并由驱油实验测出相关参数，且成功地用于软件IMCFS中。毛管数曲线QL相对更为准确地描述了复合驱驱油过程中驱替液和被驱替的油相对流动关系，软件IMCFS的成功研制为复合驱油技术研究应用提供了机理描述更完善的应用软件。

基于毛管数插值的二元驱油藏模拟方法

研究化学采油聚合物-表面活性剂二元复合驱中的毛管数曲线和相渗曲线。以毛管数与残余油关系实验曲线为基础完善了毛管数曲线数学表达式和以毛管数值为变量复合驱相渗透曲线的数学表达式,并成功用于化学驱油模拟软件中。经算例测试表明,采用新的毛管数曲线表达式和相渗曲线表达式的数值模拟更能反映复合驱采油机理和规律,适应现代采油技术的需求。

复合驱油技术应用中几项要素的优化研究

新的毛管数理论认为，当毛管数增大到一极限毛管数后，残余油达到一相对低值，毛管数进一步增大，残余油不再减少，直至毛管数增大到另一极限毛管数后，出现驱动状况转化，残余油出现复杂变化。以该理论为基础，详细介绍了通过新的毛管数实验曲线优化驱油要素的方法，即必须将驱油过程严格控制在“第一类”驱动状况下；必须从三维非均质油藏出发，同时考虑复合驱的驱替特征；应从优化渗流速度出发优化注采井距和注液速度，进而优化驱油体系黏度和界面张力。研究成果进一步推动了新毛管数理论的发展，为复合驱技术的实际应用提出了指导意见。

A new method to construct reservoir capillary pressure curves using NMR log data and its application

By analyzing hundreds of capillary pressure curves, the controlling factors of shape and type of capillary pressure curves are found and a novel method is presented to construct capillary pressure curves by using reservoir permeability and a synthesized index. The accuracy of this new method is verified by mercury-injection experiments. Considering the limited quantity of capillary pressure data, a new method is developed to extract the Swanson parameter from the NMR T2 distribution and estimate reservoir permeability. Integrating with NMR total porosity, reservoir capillary pressure curves can be constructed to evaluate reservoir pore structure in the intervals with NMR log data. An in-situ example of evaluating reservoir pore structure using the capillary pressure curves by this new method is presented. The result shows that it accurately detects the change in reservoir pore structure as a function of depth.

Supplement and optimization of classical capillary number experimental curve for enhanced oil recovery by combination flooding

In the middle of the last century,American scientists put forward the concept of capillary number and obtained the relation curve between capillary number and residual oil through experiments.They revealed that the corresponding residual oil saturation decreased with increasing of capillary number;after capillary number reached up to a limit,residual oil saturation would become stable and did not decrease.These important achievements laid a theoretical base for enhanced oil recovery with chemical flooding.On the basis of the theory,scholars developed chemical flooding numerical simulation software UTCHEM.During the numerical simulation study of combination flooding,the authors found that as the capillary number is higher than the limit capillary number,the changes of the residual oil saturation along with the capillary number differ from the classical capillary number curve.Oil displacement experiments prove that there are defects in classic capillary number experimental curve and it is necessary to mend and improve.Capillary number‘calculation’curve is obtained with a method of numerical simulation calculation and a complete description of capillary number curve is provided;On this basis,combination flooding capillary number experimental curve QL is obtained through experiments,which is different from the classical capillary curve;and based on which,an expression of corresponding combination flooding relative permeability curve QL is given and the corresponding relative permeability parameters are determined with experiments.Further oil displacement experiment research recognizes the cause of the singular changes of the capillary number curve."Combination flooding capillary number experimental curve QL"and"combination flooding relative permeability curve QL"are written in combination flooding software IMCFS,providing an effective technical support for the application of combination flooding technical research.