Tight sand gas reservoirs have the characteristics of strong heterogeneity, wide different of drainage radius, so there exit many uncertainties of well interference and interference degree when well infill is optimized.According to those uncertainties above, well interference probability simulation is needed to be researched.First, interference well ratio and interference reserve ratio are employed to estimate the degree of well interference, based on geological statistics and Metro Carlo random simulation method, a mathematical model is established for estimating interference reserves between adjacent wells under two different interference models.Finally an estimation process was proposed which consist of gas drainage reserves probability, interference well ratio probability and interference reserve ratio probability.Taking Sulige X reservoir as case study to analyze how well interference change with well infilling, the results indicate that along with encrypted well density, gas drainage reserve increase fast but growth rate slow down, interference well ratio grow rapidly to nearly 100% level very soon, interference reserve ratio increase slower than that of interference well ratio, and under same well density, interference reserve ratio is less than interference well ratio.When well pattern is optimized, interference reserve ratio should be taken as the key parameter.Simulation results correspond to reservoir dynamic performance which can prove this study can assess well interference degree under different well density and provides guidance on well pattern optimization.%低渗致密砂岩气藏储层非均质性强,气井泄气范围差异大,井网加密优化时气井之间是否干扰以及干扰程度存在不确定性;针对该问题需要开展井间干扰概率模拟方法研究.为此,提出使用干扰井数比例和干扰储量比例两个指标衡量干扰程度大小;并基于地质统计原理和蒙特卡洛随机模拟方法,建立了相邻气井两种井间干扰模式下干扰储量评价数学模型,形成了不同井网密度时井控储量概率、干扰井数比例概率和干扰储量比例概率模拟评价流程.以苏里格某区块为例探讨了井间干扰程度随井网加密的变化规律.研究结果表明:随着井网不断加密干扰井数比例迅速增加,并很快达到接近100%的水平,干扰储量比例增长速度明显慢于干扰井数比例;而且同一井网密度时干扰储量比例小于干扰井数比例.合理井网优化应更加侧重对干扰储量比例的考量.实例模拟结果与矿场动态相符,表明该方法能够有效评价井间干扰程度,为井网优化部署提供科学依据.
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