摘要
研究区在新生代为一持续下沉的断陷盆地,碎屑岩沉积厚度大,有利于研究其埋藏成岩作用。有些埋藏成岩作用是在一定的地温条件下形成的,可作为地质温度计,如石英次生加大、自生阶状石榴石、自生高岭石、溶蚀绿帘石及晚期含铁碳酸盐胶结物等。根据各种埋藏成岩作用,可划分出四个成岩带,即浅成岩带、中成岩带、深成岩带及超深成岩带,可用于划分和评价碎屑岩储层。
To study burial diagenesis is very important for reservoir assesment.Petrological datafrom 66 wells suggest that the present temperature corresponding to the depth where burialdiagenetic minerals occur is approximate or equal to the formation temperature.There-fore,the original formation temperature of the burial diagenetic minerals can be calculatedby following equation.T=G(H-h)+14.5℃where T is the original formation temperature of the burial diaganetic minerals;G isgeothermal gradient;H is the shallowest depth where this diagenesis occurs;h is the depth of constant temperature zone(assuming h=0 when T is calculated because it is verysmall in study area);14.5 is the annual average surface temperature in the area.Calcula-tion and error analysis show that the original formation temperature of different burial dia-genetic geothermometer are as follows.65±5℃ for weak overgrowth of quartz;90±5℃for intensive overgrowth of quartz;92±5℃ for authigenic garnet;95±5℃ for late car-bonate cement(such as saddle dolomite);70±5℃ for authigenic kaolinite;140±10℃for transformation from kaolinite to illite.Based on all the diagenesis related to tempera-ture,four diagenetic zones can be divided,i.e.shallow,moderate,deep and superdeepzones.It is demonstrated that these zones can be used to classify and assess reservoir rocksand source rocks.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
1990年第2期119-126,T001,共9页
Oil & Gas Geology
