低渗透底水油藏油井见水类型及影响因素研究

Study on Water Breakthrough Types and Influencing Factors of Oil Wells in Low Permeability Reservoir with Bottom Water

边底水较发育的低渗透油藏受储层特征、人为开发政策和工程等因素影响,很难确定油藏的见水类型,导致油井见水后不能制定出针对性开发措施。以水驱原理、油藏地质特征为基础,以矿场监测资料为辅助,对油井见水前后的动态进行分析,判断油井见水类型及影响因素。研究认为,S区块延9油藏油井见水类型主要是地层水,次为注入水,油井见水类型不同,见水后采出水含盐量变化规律亦不同;受储层非均质性和注水井射孔段长度影响,油井见注入水后采出水的含盐量介于原始地层水含盐量和注入水含盐量之间;影响油井见水类型的主要因素有储层地质条件、开发政策和工程因素,并对不同见水类型油井提出不同的控制含水上升方法。该研究结果可为类似油藏合理开发政策的制定提供一定的决策依据。

Low permeability reservoirs with relatively developed edge and bottom water are affected by reservoir char-acteristics,artificial development policies and engineering factors,so it is difficult to determine the water breakthrough type of the reservoir,resulting in the failure to formulate targeted development measures after water breakthrough of oil wells.Based on the principle of water flooding and the geological characteristics of oil reservoirs,and with the aid of field monitoring data,the dynamic analysis of oil wells before and after water breakthrough has been carried out,and the principles for judging water breakthrough types of oil wells have been obtained,the influencing factors of water break-through types in oil wells are analyzed.It is considered that the water breakthrough type of YAN9 oil reservoir in Block S is mainly formation water,followed by injection water,the water breakthrough type of oil well is different,and the salt content of produced water is different after water breakthrough;Due to the influence of reservoir heterogeneity and the length of perforation interval of injection wells,the salt content of produced water is between the original formation wa-ter salt content and injection water salt content.The main factors affecting water breakthrough types are reservoir geologi-cal conditions,development policies and engineering factors.Different methods to control water cut rise are proposed for different water breakthrough types of oil wells.The research results of this paper will provide some decision-making ba-sis for the formulation of reasonable development policy of similar reservoirs.