江苏句容坳陷青龙群原油演化特征及找油方向探讨

句容坳陷位于宁镇隆起区,茅山断褶带与溧水隆起之间,面积约1325平方公里。露头稀少,大部分被第四系覆盖。据重力、磁法勘探及钻井证实,坳陷北部有一个轴向北东,具南、北两个高点、被断层复杂化的背斜构造。背斜长7公里、宽1.8公里,圈闭面积约12.5平方公里。钻探揭露,背斜轴部附近上侏罗统直接覆盖在中、下三叠统青龙群之上,其间缺失中、下侏罗统象山群及上三叠统黄马青组,且青龙群上部多遭严重剥蚀。象山群仅在翼部保存。

CHARACTERISTICS OF THE EVOLUTION OF THE CRUDE OIL FROM QINGLONG GROUP OF JURONG DEPRESSION IN SOUTHERN JIANGSU AND THESTRATEGY FOR OIL FINDING

The Mesozoic Jurong depression is located in the Western part of Southern Jiangsu, with an area of about 1325 km2.Twenty-five wells were drilled on the Jurong anticline in the middle part of the depression (including 4 eoal-field exploration wells). The production of the initial test of Rong No.2 Well in lower Qinglong group (T₁) limestone was 6.6 m3/day of oil, while the highest production of Rong No.3 Well was 10.1 m3/day. Owing to the lack of formation energy, and the poor physical properties of the reservoir, the production decreased rapidly and finally dried up. The analysis of crude oil and the quality of coal indicate that this is a low mature heavy oil and lignite area. According to the graph of fixed carbon ratio distribution, middle or small pools may be found at the flanks of the depression where the degree of evolution is higher.