Abstract: The means of exploitation of low permeability oil reservoir in Changqing by single horizontal well is changed to by combination well pattern of horizontal well and vertical well,and the well pattern is mainly made of horizontal water injector and vertical oil producer.Study on vertical well deliverability by this means is less,so it is very necessary to study it deeply.According to production needs of Changqing oil field,the article takes combination well pattern of horizontal-injector and vertical-producer as example,deliverability formula of combination well pattern of horizontal-injector and verticalproducer is derived by conformal transformation,method of mirror image and complex potential overlay principle.And vertical well deliverability of combination well pattern is calculated through numerical simulation.Combined theoretical formula and numerical simulation result,the theoretical calculation value are basically consistent with the numerical result after theoretical formula is modified by introducing a correction coefficient.Influence of horizontal well length on well pattern deliverability is analyzed,which will be helpful for developing oil field by the means of combination well pattern of horizontal well and vertical well.

Key words: low permeability, horizontal well, vertical well, combination well pattern, deliverability calculation, correction coefficient