准噶尔盆地腹部深层—超深层碎屑岩储层发育特征与孔隙演化定量表征

Development characteristics and quantitative characterization of pore evolution of deep and ultra-deep clastic reservoirs in the hinterland of the Junggar Basin

张关龙 王继远 王斌 刘德志 郑胜 穆玉庆 邱岐

ZHANG Guanlong WANG Jiyuan WANG Bin LIU Dezhi ZHENG Sheng MU Yuqing QIU Qi

中国石化 胜利油田分公司 勘探开发研究院，山东 东营 257001 中国石化 石油勘探开发研究院 无锡石油地质研究所，江苏 无锡 214126 中国石化 油气成藏重点实验室，江苏 无锡 214126

Exploration & Development Research Institute, Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257001, China Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms, Wuxi, Jiangsu 214126, China

腹部下组合(二叠系—三叠系)是准噶尔盆地油气勘探重要的战略接替领域。多井钻揭6 km以下优质碎屑岩储层，大大突破了传统碎屑岩有效储层埋深下限，明确储层发育状况及孔隙演化过程是确定油气能否富集成藏的关键问题。以腹部地区典型钻井为例，综合岩石薄片镜下分析、孔渗测试、图像分析技术、孔隙度演化定量表征及包裹体测温和盆地模拟等方法，从定性和定量的角度全面剖析准噶尔盆地腹部下组合深层—超深层碎屑岩储层的岩石学、物性及孔隙结构特征，并定量恢复孔隙演化过程。结果表明，腹部下组合中三叠系百口泉组砂体最为发育，二叠系上乌尔禾组及三叠系克拉玛依组次之；各层位岩石类型均以岩屑砂岩为主，少量长石岩屑砂岩，岩屑成分主要为中—基性火山岩屑，长石、石英含量偏低，二者之和普遍低于20%；克拉玛依组原生孔隙发育，物性最好，孔隙度最高可达13.18%。上乌尔禾组和百口泉组以次生溶蚀孔为主，溶蚀物质主要为中—基性火山岩屑、浊沸石胶结物及少量长石，二者物性较其上覆克拉玛依组差；克拉玛依组孔隙演化经历较弱压实(压实减孔量21.08%)、弱胶结(胶结减孔量2.88%)和弱溶蚀(溶蚀增孔量1.4%)，现今高孔隙度主要得益于弱压实、晚期弱胶结作用下原生孔隙的大量保存；百口泉组和上乌尔禾组经历强压实(压实减孔量分别为26.60%和26.43%)、强胶结(胶结减孔量分别为7.43%和11%)和中等—强溶蚀(溶蚀增孔量分别为6.32%和4.21%)，溶蚀作用是二者增孔的最主要途径，但不足以弥补强压实和强胶结的减孔效应，导致二者现今孔隙度较低。

The lower play (Permian to Triassic) in the hinterland is the most important strategic succession field for oil and gas exploration in the Junggar Basin. Multiple wells have been drilled into high-quality clastic rock reservoirs below 6 000 m, greatly breaking through the deadline of buried depth of traditional clastic rock effective reservoirs. It has been made clear that the development status and pore evolution process are the key issues that determine whether oil and gas can be accumulated. Taking typical drilling wells in the hinterland as an example, this paper comprehensively analyzed the petrology, physical properties and pore structure characteristics of deep and ultra-deep clastic reservoirs in the hinterland of the Junggar Basin from a qualitative and quantitative perspective, and quantitatively restored the pore evolution process by integrating the microscopic analysis of rock thin sections, porosity and permeability tests, image analysis technology, quantitative characterization of porosity evolution, temperature measurement of inclusions, basin modeling and other methods. The results show that the clastic rock in the lower play of the hinterland is mainly developed in the Permian Upper Wuerhe Formation, Triassic Baikouquan Formation and Triassic Kelamayi Formation, of which the sand in the Triassic Baikouquan Formation is the most developed, followed by the Permian Upper Wuerhe Formation and Triassic Kalamayi Formation. There is little difference in rock types among different layers, which mainly composed of lithic sandstone with a small amount of feldspar lithic sandstone. The composition of rock debris is mainly medium-basic volcanic rock debris, with low content of feldspar and quartz, and the sum of them is generally less than 20%. The Kelamayi Formation is dominated by primary pores with the best reservoir property and the highest porosity of 13.18%. The Upper Wuerhe Formation and Baikouquan Formation are dominated by secondary corrosion pores, and the corrosion materials are mainly medium-basic volcanic debris, laumontite cement and a small amount of feldspar. The reservoir properties of them are not as good as those of the Kelamayi Formation. The pore evolution of the Kelamayi Formation has experienced weak compaction (21.08% pore reduction by compaction), weak cementation (2.88% pore reduction by cementation), and weak corrosion (1.4% pore increase by corrosion). Today's high porosity is mainly due to the large amount of preservation of primary pores under weak compaction and late weak cementation. The Baikouquan Formation and Upper Wuerhe Formation have undergone strong compaction (26.60% and 26.43% pore reduction by compaction, respectively), strong cementation (7.43% and 11% pore reduction by cementation, respectively), and strong corrosion (6.32% and 4.21% pore increase by corrosion, respectively). Secondary corrosion is the main way for them to increase porosity, but it is insufficient to compensate for the porosity reduction effect of strong compaction and cementation, resulting in lower porosity in the two formations.

中国石化科技部项目“准噶尔盆地石炭—二叠系潜力评价与目标优选” P21077-1;“准噶尔盆地腹部下组合油气成藏条件与勘探方向” P22132

https://doi.org/10.11781/sysydz202304620