断裂带作为油气散失通道的输导能力

DRAINING CAPACITY OF FAULT ZONE AS A PATHWAY OF OIL AND GAS LEAKAGE

通过断裂散失的油气量主要与断裂带的输导能力、实际进入断裂带的油气量、断裂通道的长度、散失时间和储层分流系数等参数有关。断裂带输导能力的主要因素是断裂带的宽度和储层渗透率。利用断裂散失模型计算了不同规模的断裂带作为油气散失通道的输导能力。计算结果表明 ,大型断裂带输导油气的能力远大于储层输导油气的能力。断裂活动期进入“通天”大断裂带的油气主要趋于散失 ;小断裂由于储层的分流作用 ,即使在活动期 ,它作为油气散失通道的作用也是有限的 ,其油气的散失量可以忽略不计。

The leakage of oil and gas passing through a fault zone is mainly controlled by the draining capacity of the fault zone, the amount of oil and gas into the fault, the length of the leaking pathway, the leaking time and the parameters for dividing process of reservoir. The main parameters controlling the draining capacity of a fault zone are the width and the permeability of the fault zone. The former can be calculated with the fault displacement measured in seismic section, and the latter can be obtained from the porosity of the fault zone measured by sonic log. A calculation model for draining capacity of a fault zone is built on the basis of fault leakage model. The calculation shows that the oil and gas migrated into a large fault during its active period would mostly tend to be dissipated, whereas those interred a small fault would all be divided into the different reservoirs.