大牛地致密气田剩余气分布类型及提高采收率技术

Remaining gas distribution pattern and enhanced oil recovery methods in Daniudi tight gas field

致密砂岩气储层具有物性差、非均质性强等特点,导致地质认识程度低、一次井网难以有效控制、采收率低等问题。以大牛地致密气田石炭—二叠系储层为研究对象,首先明确影响该气田采收率的关键因素为储层特征、渗流特征及开发方式。在单砂体描述的基础上建立气藏精细三维地质模型,综合生产动态数据和动态监测数据,将剩余气分布类型细分为8种类型:远端未波及型、井间未波及型、井间未控型、渗流阻隔型、未打开型、层间干扰型、水锁抑制型和水包气型。以降低废弃压力、增加沟通体积和提高动用程度为目标,提出了3种提高采收率技术:基于单砂体描述的井网优化调整技术、基于储层保护的补孔合采技术、基于积液早期判识的排水采气技术。本文研究可为类似致密气田开发提供借鉴。

Tight sandstone gas reservoir is characterized by poor physical properties and strong heterogeneity,leading to low geological understanding,difficulty in effective control of primary well networks and low recovery efficiency.Taking the Carboniferous-Permian reservoir in the Daniudi tight gas field as the research object,it is identified that the key factors affecting the recovery efficiency of the gas field are reservoir characteristics,seepage characteristics and development methods.Based on the description of a single sand body,a fine 3D geological model of the gas reservoir was established,and the dynamic production data and monitoring data were integrated to subdivide the remaining gas distribution pattern into eight types:distal unperturbed,inter-well unperturbed,inter-well uncontrolled,seepage barrier,unopened,inter-layer interference,water lock inhibition and gas-in-water.With the objectives of reducing abandonment pressure,increasing communication volume and improving mobilization,three recovery enhancement techniques are proposed:well network optimization adjustment technique based on single sand body description,hole patching and commingled production technique based on reservoir protection,and drainage gas recovery technique based on early identification of fluid accumulation.The research in this paper may provide a reference for the development of similar tight gas fields.