伊拉克X油田碳酸盐岩隔夹层隐蔽性特征及封隔性评价  

Hidden characteristics and sealed property evaluation of carbonate baffles and barrier in X Oilfield,Iraq

作　　者：李峰峰 李蕾 万继方 杨超[1] 陈家恒 LI Fengfeng;LI Lei;WAN Jifang;YANG Chao;CHEN Jiaheng(Research Institute of Petroleum Exploration&Development,Beijing 100083,China;China Energy Digital Technology Group Company Limited,Beijing 100044,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中能建数字科技集团有限公司,北京100044

出　　处：《中国石油大学学报（自然科学版）》2024年第4期1-11,共11页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：中国石油集团科技重大专项(2023ZZ19-01,2023ZZ19-07)。

摘　　要：基于钻井取芯、试验分析和生产测试等资料,以伊拉克X油田白垩系Mishrif油藏为例,分析生物碎屑灰岩隔夹层隐蔽性特征,以渗透率作为隔夹层主判别参数,宏观与微观互相验证,动静态数据相结合,统计地层压力梯度异常段的渗透率值,确定具有封隔能力的隔夹层识别标准。在统计地层压力梯度异常段时,基于生产测试数据,确定产层的渗透率下限,排除产液造成的地层压力异常;基于微观结构分析确定非渗透层上限,排除压力异常段中渗透层对统计结果的影响。结果表明,生物碎屑灰岩隔夹层的隐蔽性体现在:岩性多样,包括含粒泥晶灰岩、粒泥灰岩、泥粒灰岩、亮晶颗粒灰岩等,颗粒组分为复杂的生物介壳碎屑;低能环境中可发育岩性隔夹层,高能环境与胶结作用相耦合可发育物性隔夹层;孔渗相关性差,隔夹层可具有较高的孔隙度,喉道半径通常小于0.5μm,但孔喉结构差异大;厚度从十几厘米到几十米变化,侧向尖灭快,叠置样式多样;隔夹层的低渗特征在测井上响应较弱,测井判别易发生“误判”或“漏判”。X油田Mishrif油藏隔层渗透率小于0.5×10^(-3)μm^(2),厚度大于2.5 m,夹层渗透率小于0.65×10^(-3)μm^(2),厚度大于1 m。MA段和MB1段封隔性较好,可作为两套开发层系部署不同井网;MB1段和MB2段封隔性较差,分层系注水开发中垂向上存在窜流风险;MB2和MC封隔性较好,将其作为一套开发层系不合理,底注顶采的开发方式将会受效较差。层间封隔性分析论证了巨厚油藏分层系注水开发的可行性,为开发策略调整提供地质依据。Based on core samples,experimental data,and production logging tests,this study analyzes the hidden characteristics of baffles and barriers in the Cretaceous Mishrif Formation of the X Oilfield in Iraq.By using permeability as the main discriminant parameter for baffles and barriers,a combination of macroscopic and microscopic mutual verification,dynamic and static data integration,and the permeability values of abnormal interval of formation pressure gradient,was employed to determine the criteria of baffles and barriers with sealing ability.To account for production-induced pressure abnormalies,the lower permeability limit of the production zone was determined using production logging tests.The upper limit of the non-permeable layer was defined based on microstructure analysis,excluding the influence of permeable layers within abnormal pressure intervals on the statistical results.The findings reveal that the hidden baffles and barriers in bioclastic limestone manifest in various lithologies,including mudstone with grains,wackstone,packstone,and calcsparite grainstone,with diverse and complex biological shell clasts.Lithologic baffles and barriers form in low-energy environments,whereas physical baffles and barriers develop in high-energy environments with cementation.The correlation between porosity and permeability is poor,with baffles and barriers often having pore throats less than 0.5μm,with variable microstructure.The thickness ranges from several centimeters to dozens of meters,with lateral pinch-out and diverse overlapping styles.The low permeability characteristics of baffles and barriers have weak logging responses,leading to potential misinterpretations or missed identifications.Specifically,baffles exhibit permeability less than 0.5×10^(-3)μm^(2) and thickness greater than 2.5 m,while barriers have permeability less than 0.65×10^(-3)μm^(2) and thickness over 1m.It is concluded that MA and MB1 zones exhibit good sealing performance and shoud be treated as separate development units with distinct

关 键 词：生物碎屑灰岩 隔夹层 封隔性 巨厚油藏 隐蔽性 分层系开发 

分 类 号：TE122.2[石油与天然气工程—油气勘探]