特低渗透油藏单井产量递减规律及其影响因素——以长庆油田盘古梁长6油藏为例

Oil well production decline rules and influence factors of extra-low permeability oil reservoir-case of Panguliang Chang 6 reservoir,Changqing oilfield

在油田开发过程中,低渗透和特低渗透油藏必然存在一个产量递减阶段。过去的研究主要集中在整个油田的产量递减规律分析及递减模型的建立,忽略了单井产量递减规律及影响因素的研究。通过对长庆油田盘古梁长6特低渗透油藏单井产量的研究发现:单井产量的递减形态主要分为递减Ⅰ型和递减Ⅱ型;递减类型主要分为指数递减和调和递减,且以指数递减为主,同时递减类型随着开发方式的转变可相互转化;影响单井产量递减的主要因素有储层物性、天然能量、注水效果、工作制度和增产措施等,而投产初期的主要影响因素是油层物性和天然能量。

In the process of oilfield production,in particular,low permeability or extra-low permeability oil reservoir exists a decline phase,the previous research focused mainly on the analysis and the model of oil production decline rule of the oilfield but ignored the research of well production decline rule.The research on production of well in Changqing oilfield's Panguliang Chang 6 extra-low permeability oil reservoir shows that there are two main types of oil well production decline type,that is,decline type 1 and 2.Analyzed from the decline type,it will be exponential decline and harmonic decline,and mainly attributed to the former. Meanwhile,the decline types can switch and transform to each other with the change of development mode.The main factors affecting production decline are mainly caused by physical properties of oilfield,natural energy,working system,water injection efficiency, reasonably producing pressure differential,fracturing and acidizing etc.However,in the beginning of production,the main factors are physical properties of oilfield and natural energy,and energy will drop quickly.