石油学报 ›› 2019, Vol. 40 ›› Issue (6): 677-691.DOI: 10.7623/syxb201906004

• 地质勘探 • 上一篇    下一篇

中东地区巨厚强非均质碳酸盐岩储层分类与预测——以伊拉克W油田中白垩统Mishrif组为例

刘航宇1, 田中元2, 刘波3, 郭睿2, 石开波1, 叶玉峰4   

  1. 1. 北京大学地球与空间科学学院 北京 100871;
    2. 中国石油勘探开发研究院 北京 100083;
    3. 北京大学石油与天然气研究中心 北京 100871;
    4. 中国石油国际勘探开发有限公司 北京 100034
  • 收稿日期:2018-11-27 修回日期:2019-04-26 出版日期:2019-06-25 发布日期:2019-07-02
  • 通讯作者: 刘波,男,1965年4月生,1986年获成都地质学院学士学位,1997年获北京大学博士学位,现为北京大学石油与天然气研究中心副主任、研究员,主要从事盆地构造-沉积演化、储层沉积学、层序地层学、碳酸盐岩沉积-成岩作用研究。Email:bobliu@pku.edu.cn
  • 作者简介:刘航宇,男,1992年7月生,2015年获中国石油大学(华东)学士学位,2018年获中国石油勘探开发研究院硕士学位,现为北京大学博士研究生,主要从事碳酸盐岩储层相关研究工作。Email:hy_liu@pku.edu.cn
  • 基金资助:

    国家科技重大专项(2017ZX05005-003-005,2017ZX05030-001)和国家自然科学基金项目(No.41572117)资助。

Classification and prediction of giant thick strongly heterogeneous carbonate reservoirs in the Middle East area: a case study of Mid-Cretaceous Mishrif Formation in the W oilfield of Iraq

Liu Hangyu1, Tian Zhongyuan2, Liu Bo3, Guo Rui2, Shi Kaibo1, Ye Yufeng4   

  1. 1. School of Earth & Space Sciences, Peking University, Beijing 100871, China;
    2. PetroChina Research Institute of Petroleum Exploration & Development, Beijing 100083, China;
    3. Institute of Oil & Gas, Peking University, Beijing 100871, China;
    4. China National Oil and Gas Exploration and Development Company Ltd., Beijing 100034, China
  • Received:2018-11-27 Revised:2019-04-26 Online:2019-06-25 Published:2019-07-02

摘要:

巨厚碳酸盐岩储层是中东波斯湾盆地发育较普遍的一类储层,受控于复杂原生沉积-次生成岩改造作用,储层岩石类型与孔隙结构复杂、非均质性极强,严重制约着巨厚油藏注水开发采收率的提高。以伊拉克W油田中白垩统Mishrif组巨厚碳酸盐岩为例,通过岩心、测井、地震和物性、压汞等资料,以"储层成因(沉积+成岩)为分类基础、储层质量(物性+微观孔隙结构)为分类依据、地球物理方法(测井+地震)为识别预测手段",开展复杂强非均质碳酸盐岩储层分类与预测研究。研究表明:沉积相带及其变迁控制了Mishrif组复杂岩石结构类型及叠置关系,原始沉积组构叠加差异性成岩改造控制了其6种孔隙类型的发育及分布,发育14种岩石成因类型,每种类型具有相似的沉积结构和孔隙类型,且经历了统一的沉积-成岩演化史。岩石成因类型与储层质量相关性好,根据储层质量划分为5种储层类型,其中发育粒间孔、混合孔的生屑砾屑灰岩和发育粒间孔的生屑砂屑灰岩,属于高孔高渗连通孔粗喉型最优质储层。构建测井声波纵波波阻抗(RHOB/DT)和深感应电阻率与自然伽马测井数值之比(RILD/GR)交会图,其对单井储层类型识别效果较好。以单井测井识别结果为硬数据,以地震波阻抗为井间约束,预测各类储层空间展布,其中I类最优质储层在mB2上段呈大范围片状连续分布,mB1段呈条带状分布,mA段呈小范围片状分布,分别符合mB2上段台地边缘生屑滩、mB1段台内潮汐水道和mA段台内浅滩沉积环境。通过盲井抽稀检验,预测结果符合率超过80%,从而为剩余油挖潜奠定了基础。

关键词: 伊拉克, 中白垩统, Mishrif组, 碳酸盐岩储层, 成因, 分类, 测井识别

Abstract:

The giant thick carbonate reservoir is a kind of reservoir generally developed in the Persian Gulf Basin of the Middle East. The reservoir rock type and pore structure are complex with extreme strong heterogeneity, which is controlled by complex primary sedimentation and secondary diagenesis alteration, severely restricting the improvement of oil recovery by water-flooding development in giant thick reservoirs. Taking the giant thick carbonate rocks of Mid-Cretaceous Mishrif Formation of the W oilfield in Iraq as an example, using the cores, logging, seismic and physical properties, mercury injection and other data, a study was carried out on the classification and prediction of complex and highly heterogeneous carbonate reservoirs; the reservoir genesis (sedimetion+diagenesis)was taken as a basis for classification, the reservoir quality (physical properties+microscopic pore structure)as a classification criterion, and the geophysical method (well logging+seismic)as a means for identification and prediction. The study shows that the sedimentary facies belt and its changes control the complex rock structure types and their overlapping relationships in the Mishrif Formation. The original sedimentary structure and diagenetic alteration control the development and distribution of six types of pore; 14 rock genesis types are developed with similar sedimentary rock structures and pore types, undergoing the same sedimentary-diagenetic evolution history. The genetic type has a good correlation with reservoir quality. According to reservoir quality, the genetic type is divided into five reservoir types, among which the bioclastic rudstone with intergranular pores and mixed pores as well as bioclastic grainstone with intergranular pores belong to the highest quality reservoir with high porosity and high permeability as well as interconnected pore and coarse throat. The crossplot of longitudinal log acoustic wave impedance (RHOB/DT), deep induction resistivity and natural gamma log (RILD/GR)ratio has been constructed, presenting a better identification effect on single well reservoir type. Using the single well logging identification results as hard data, and the seismic wave impedance as the well constraint, this study makes a prediction on the spatial distribution of various reservoirs. The highest quality reservoir of Type I presents a continuous, wide and sheet-shaped distribution in the upper mB2 interval, a strip-like distribution in the mB1 interval and a small-scale sheet-shaped distribution in the mA interval, corresponding to the sedimentary environment of the platform margin bioclastic shoal in the upper mB2 section, the intra-platform tidal channel in the mB1 interval, and the intra-platform shoal in the mA interval respectively. Through the validation of blind well test, the coincidence rate of the predicted results exceeds 80%, laying a fundation for remaining oil recovery.

Key words: Iraq, Mid-Cretaceous, Mishrif Formation, carbonate reservoir, genesis, classification, well logging identification

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