摘要
珠江口盆地深水区古潜山钻井资料极少,严重制约了古潜山有利储层的预测和天然气勘探进程。为此,以该盆地白云凹陷东部古潜山为例,综合利用井资料和高精度三维地震数据,对该古潜山的强风化淋滤带储层分布进行了重点解剖,在明确其储层微观和测井响应特征的基础上,通过井—震标定,依托高精度三维地震数据揭示了古潜山强风化淋滤带储层的分布规律,并探讨其主控因素。研究结果表明:①古潜山强风化淋滤带储层具有低密度的测井响应特征,其内部斜长石和云母等矿物严重蚀变,斜长石内的裂缝因强烈的溶蚀改造变宽和不同程度弯曲;②古潜山强风化淋滤带储层在地震剖面上呈空白反射,且具有明显的垂向非均质性,分布在古潜山现今地貌西部的高点和东部的斜坡上;③在始新世早期及其之前,该区古潜山均位于古地貌高点,长期的强风化淋滤作用有效地促进了强风化淋滤带的形成,中—晚始新世,东强西弱的差异伸展导致西部强风化淋滤带仍处于地貌高点,而东部则由于断块旋转和岩浆底侵导致的抬升转变为现今的斜坡部位。结论认为,大气降水沿古潜山内幕断裂的差异渗流导致了差异风化,造就了古潜山强风化淋滤带储层的垂向非均质性;古地貌是主控古潜山强风化淋滤带储层东西差异分布的主要因素。
The prediction of favorable reservoirs and the progress of natural gas exploration in the deep-water buried hills of the Pearl River Mouth Basin are seriously restricted due to scarce well drilling data.Taking the buried hill in the east of Baiyun sag as an example,this paper mainly dissects the distribution laws of its intensively weathering and leached zones by making comprehensive use of well data and high-accuracy 3D seismic data.Then,the microscopic and logging response characteristics of the intensively weathering and leached zones are clarified.Based on this,the distribution laws of the intensively weathering and leached zones are revealed by means of well-seismic calibration,combined with high-accuracy 3D seismic data.Finally,the factors controlling the distribution laws of the intensively weathering and leached zones are discussed.And the following research results are obtained.First,the intensively weathering and leached zones in the buried hill show low-density logging response characteristics.The plagioclase and mica in these zones suffer severe alteration,and the fractures in the plagioclase get wide and bend in different degrees under the action of intensive dissolution reworking.Second,these are characterized by blank seismic reflections and significant vertical heterogeneity.They are distributed in the current western geomorphologic high and the eastern slope of the buried hill.Third,before and during the Early Eocene,the buried hills in this area were all located at the palaeogeomorphologic high,where the prolonged weathering-leaching process effectively promoted the formation of intensively weathering and leached zones.During the Middle to Late Eocene,the intensively weathering and leached zones in the west were still at the palaeogeomorphologic high due to the differential extension which was strong in the east but weak in the west,while the eastern area was transformed into the current slope due to the uplift caused by fault block rotation and magma underplating.In conclusion,the differential seepage of atmospheric precipitation along the faults and fractures inside the buried hill leads to differential weathering,resulting in vertical heterogeneity of the intensively weathering and leached zones.What's more,palaeogeomorphology is the main factor controlling the differential distribution of intensively weathering and leached zones of buried hill in the west and the east.
作者
彭光荣
张丽丽
吴哲
谢世文
赵俊峰
路繁荣
梁超
潘杰
黄雷
PENG Guangrong;ZHANG Lili;WU Zhe;XIE Shiwen;ZHAO Junfeng;LU Fanrong;LIANG Chao;PAN Jie;HUANG Lei(CNOOC China Limited Shenzhen Company,Shenzhen,Guangdong 518054,China;Department of Geology,Northwest University,Xi'an,Shaanxi 710069,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2024年第1期97-107,共11页
Natural Gas Industry
基金
国家自然科学基金项目“海底峡谷沉积构型转换成因及其地质响应——以琼东南盆地松南凹陷晚中新世以来海底峡谷为例”(编号:42202124)
中海石油(中国)有限公司重大科技项目“南海大中型天然气田形成条件、勘探潜力与突破方向”(编号:KJZH-2021-0003)
中海石油(中国)有限公司“十四五”重大科技项目“中国近海新区新领域勘探技术”(编号:KJGG2022-0302)。
关键词
珠江口盆地
白云凹陷
强风化淋滤带
古潜山
古地貌
储层非均质性
Pearl River Mouth Basin
Baiyun sag
Intensively weathering and leached zone
Buried hill
Palaeogeomorphology
Reservoir heterogeneity
