低渗气藏多层合采技术界限图版法

CHART BOARD METHOD OF THE TECHNICAL LIMIT FOR THE COMMINGLED PRODUCTION OF LOW-PERMEABILITY GASFIELD

中国西部的气藏大多为低渗致密的多层气藏，由于其自身复杂的地质特征，采用单层开采效果差，而采用多层合采开采方式能有效地提高气井产能，延长稳产期。但多层合采使得气藏及井底渗流特征复杂化，层间干扰现象将影响气井的开采效果，而对于气井多层合采的技术界限目前却鲜有研究。在建立层间无窜流的单井多层气藏双孔介质模型基础上，利用数值模拟方法，从气藏压力和储层物性参数方面进行大量的计算分析，获得了低渗气藏多层合采的技术界限图版。分析表明多层合采的有利区域为近似菱形的狭窄区域，合采产层的压力系数比和渗透率比必须处于合采有利区域才能进行合层开采，并通过实例应用表明该方法是合理可行的，对开发层系划分与组合、单井采气方式的确定以及气井开采后期实施调转层措施都具有重要的指导意义。

For the most gasfields in West China, many reservoirs are characterized by lowpermeability and tight layers, due to their complicated geological features and poor production effects by single reservoir, on the contrary, their commingled production can effectively increase the gas production and furthermore extend the stable produc tion period. But the later production process can make the characteristics of the gasfield and well bottom flow com plicated, and more seriously the interlayered interferences can influence the production effects of the gas wells. But up to now, the technical limit of the production method is seldom studied. On the basis of the established dualpo rosity media model for the individualwell and multilayed gas reservoir without any cross flow among the layers, with the help of numerical simulation method, a great amount of calculation and analyses are conducted from the aspects