中低渗油藏高含水后期储层特征、损害因素及对策——以南堡1-5区东一段为例

Damage mechanism analysis and solutions of thelater stage of high water-cut,mid-low permeability reservoir--Taking Dongying Formation Member 1 of Nanpu Sag as an Example

该文以南堡1-5区东一段为例,开展了高含水开发后期储层特性、剩余油分布规律及损害因素评价研究,结果表明该油藏储层物性下降、孔喉尺寸降低,剩余油多滞留于孔喉细小的低渗透条带中,其损害因素以水锁损害为主,其次为固相损害及液相敏感性。从提高广谱性成膜封堵及防水锁能力入手,对油层段钻井液体系进行了优化,优化后配方对储层岩心渗透率恢复值达到92%以上,现场应用平均日产油量明显提高,满足了南堡凹陷东一段中低渗高含水油藏保护需求。

Taking Dongying Formation Member 1 of 1-5 Block,Nanpu Sag as an example,studies on reservoir characteristics and remaining-oil distribution and reservoir damage mechanism were carried on.With the development of the block,physical properties decreased,pore throat size decreased,heterogeneity increased,remaining oil was mostly trapped in the low permeability strip that has smaller pore throat and higher capillary force.The main damage factors of the low permeability strip were water lock damage,followed by solid phase damage and fluid sensitivity.Proceeding from improving the ability of broad-spectrum film-forming plugging and water-lock prevention,drilling fluid system is improved through optimization of the type and gradation of plugging agent and waterproof locking agent.The core permeability of the improved drilling fluid system can be recovered to over 92%.Field application results show that the average daily production has been significantly increased,the proposed scheme can effectively meet the need of reservoir protection in the later stage of development of high water-cut,mid-low permeability reservoir.