摘要
浙皖长广地区龙潭组(P_(1～2)l)砂体有广泛油气显示,并能流出一定量原油,但砂体经历了强烈的成岩改造,十分致密,是至今未获具经济价值油流的主要原因。为全面评价龙潭组储层,从中寻找相对高孔、高渗储层的可能性,系统研究了龙潭组砂体的成岩作用和孔隙演化。本文应用80年代发展起来的成岩体系中有机-无机相互反应的新理论,建立了龙潭组砂体的成岩模式,探索性地恢复了龙潭组砂体的孔隙演化史、成油高峰期砂体孔隙度和可保存孔隙度。提出了龙中Ⅰ段的中—粗粒以上河道砂岩最有利于孔隙保存,其性质最好,是最有前景的勘探目的层。
Region studied is located in an area between Changxing (Zhejiang province) and Guangde counties, including Meishan, Jinshan and Xinhang synclines, with an area of 285km^2. Oil and gas are distributed extensively in this region, mainly in the sand bodies in Longtan group (P_(1～2)l), especially in middle Longtan group. In underground galleries in some coal mine, a certain amount of crude oil has been obtained from sand stones in first section of middle Longtan group, up to some tenth of kg per day. Organic geochemical study has identified that crude oil from these sand bodies comes from source rocks in Longtan group itself. Though oil and gas shows are observed extensively in Longtan group, neither in exploratory well nor in gallery in any coal mine and on the outcrops has obtained commercial oil and gas flow until now, the main reason is that the petrophysical properties of these sand bodies are extremely poor, with a porosity of<7％ and a permeability of<(0.1～1.0)×10^(-3)μm^2. Only a small portion of these sandstones has a better porosity and permeability and better oil and gas shows as well as small amount of oil flow are obtained from such sandstones. Depositional environments of the main sandstones in Longtan group indicate that they will be good reservoir rocks and the extremely poor current petrophysieal properties is the result of extreme strong digenesis which had occured during their burial.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
1993年第1期39-47,共9页
Petroleum Exploration and Development
