珠江口盆地陆丰凹陷文昌组凝灰质砂岩储层成岩相及发育模式
Diagenetic facies and development model of tuffaceous sandstone reservoirs in Wenchang Formation in Lufeng Sag,Pearl River Mouth Basin
李晓艳 1丁琳 1李小平 1肖张波 1吴琼玲 1张月霞 1刘金良1
作者信息
- 1. 中海石油(中国)有限公司深圳分公司,广东深圳 518000
- 折叠
摘要
陆丰凹陷文昌组深层砂岩储层是珠江口盆地珠一坳陷最重要的油藏储集岩之一,而凝灰质发育导致储层致密,渗透率呈现低渗、特低渗特征.由于凝灰质影响,该区成岩作用及其展布表现出特殊性.运用偏光显微镜在对凝灰质砂岩储层的成岩作用、自生矿物转化及孔隙类型详细观察的基础上,结合扫描电镜、孔渗测试及测井资料分析,对陆丰凹陷文昌组凝灰质砂岩储层成岩相及其发育模式进行了研究.结果表明,凝灰质蚀变作用是影响储层物性的主要成岩作用,其次是压实作用和溶蚀作用.依据各种成岩作用强度及其组合,储层整体可以分为5种成岩相:①中压实-弱胶结-凝灰质中等溶解相(Ⅰ类);②中强压实-弱胶结-凝灰质强溶解相(Ⅱ类);③中强压实-磷灰石中强胶结-中等溶解相(Ⅲ类);④中强压实-高岭石中强胶结-弱溶解相(Ⅳ类)和⑤强压实-弱胶结-弱溶解相(Ⅴ类).其中Ⅰ类成岩相为优质成岩相(孔隙度均值为13.4％、渗透率均值为5.4 × 10-3 μm2),Ⅱ类成岩相为有利成岩相(孔隙度均值为15.4％、渗透率均值为1.5 ×10-3 μm2),Ⅲ类和Ⅳ类成岩相为潜在有利成岩相(孔隙度均值为15.0％、渗透率均值为1.0 ×10-3 μm2),V类成岩相为不利成岩相.受大气水淋滤和有机酸溶蚀等影响,陆丰凹陷文昌组深层砂岩储层主要发育Ⅱ-Ⅲ-Ⅳ-Ⅴ和Ⅰ-Ⅴ两种成岩相组合模式.成岩相与储层质量密切相关,通过识别优质成岩相可以预测有利储层分布,为油气勘探提供地质依据.
Abstract
The deep sandstone reservoirs of Wenchang Formation in Lufeng Sag is one of the most important reservoir rocks in Zhuyi Depression of the Pearl River Mouth Basin,and the development of tuff leads to tight reser-voir with low permeability and ultra-low permeability.Due to the influence of tuff,the diagenesis and its distribu-tion in this area exhibit special characteristics.Based on the detailed observation of the diagenesis,transformation of authigenic minerals,and pore types of tuffaceous sandstone reservoirs using a polarizing microscope,combined with the analysis of scanning electron microscopy,pore permeability testing,logging data,the diagenetic facies and development model of the Wenchang Formation tuffaceous sandstone reservoir in the Lufeng Sag were studied.The results indicate that tuffaceous alteration is the main diagenetic process affecting reservoir properties,followed by compaction and dissolution.According to the intensity and combination of various diagenetic processes,the reser-voir can be divided into five diagenetic types:①medium compaction-weak cementation-medium tuffaceous dissolu-tion phase(type Ⅰ);②medium strong compaction-weak cementation-strong tuffaceous dissolution phase(typeⅡ);③medium strong compaction-medium strong apatite cementation-medium dissolution phase(type Ⅲ);④medium strong compaction-medium strong kaolinite cementation-weak dissolution phase(type Ⅳ)and ⑤strong compaction-weak cementation-weak dissolution phase(type Ⅴ).Among them,the type Ⅰ is high-quality diage-netic facies(with an average porosity of 13.4％and permeability of 5.4 × 10-3 μm2),the Type Ⅱ is favorable di-agenetic facies(with an average porosity of 15.4％and permeability of 1.5 × 10-3 μm2).The type Ⅲ and Ⅳ are potential favorable diagenetic facies(with an average porosity of 15.0％and permeability of 1.0 × 10-3 μm2),and the Type Ⅴ is unfavorable diagenetic facies.Affected by atmospheric water leaching and organic acid dissolution,the deep sandstone reservoirs in the Wenchang Formation of the Lufeng Sag mainly develop two types of diagenetic facies combinations:Ⅱ-Ⅲ-Ⅳ-Ⅴ,and Ⅰ-Ⅴ.Diagenetic facies are closely related to reservoir quality.Identif-ying high-quality diagenetic facies can predict the distribution of favorable reservoirs and provide geological basis for oil and gas exploration.
关键词
凝灰质砂岩/低渗储层/成岩演化/成岩相/文昌组/陆丰凹陷/珠江口盆地Key words
tuffaceous sandstone/low permeability reservoirs/diagenetic evolution/diagenetic facies/Wenchang Formation/Lufeng Sag/Pearl River Mouth Basin引用本文复制引用
基金项目
国家科技重大专项(2016ZX05024-004)
中国海洋石油集团有限公司重大科技项目(十四五)(KJGG2022-0403)
出版年
2024
NETL
NSTL
万方数据