塔东地区下古生界原油裂解气资源评价

Resources Assessment of the Lower Paleozoic Oil Cracked Gas in Eastern Tarim Basin

通过系统测定塔东地区下古生界烃源层和储层中的固体沥青含量,进而估算了原油裂解气资源量。整体来看,塔东地区下古生界原始烃源岩曾具有巨大的生烃潜力,并且曾生成过大量原油。在区块上,单位面积固体沥青含量由西向东依次增高;在层位上,中寒武统(烃源层)含固体沥青最多;在期次上,以较早期生成的固体沥青为主,较晚期生成的固体沥青为次;在赋存空间(储集层与烃源层)上,绝大部分(87%)固体沥青均停留在烃源层中,储集层中固体沥青仅占固体沥青总量的13%。裂解生气量、裂解气资源量和固体沥青含量是密切相关的,它们的分布特征也与固体沥青相同,考虑固体沥青的形成期次,遴选适宜的聚集系数,最终计算塔东地区下古生界裂解气资源量为(2.18～4.37)×1012m3,表明塔东地区下古生界具有较好的天然气勘探潜力。

According to the systematically testing solid bitumen content of the Lower Paleozoic source rock and reservoir in Tadong, the eastern Tarim basin, we have estimated the cracked gas resources in the pa per. On the whole, the Lower Paleozoic source rock has a tremendous hydrocarbon generating potential and generates a great deal of crude oil at one time in Tadong. At the blocks, the solid bitumen content per unit area increases from west to east. In horizons, the solid bitumen is much more in the Middle Cambrian source rock than that in any others. With respect to the stages, the early solid bitumen is more than that in late one. In accumulating position （in reservoir or in source rock）, most of solid bitumen, 87%, rests on the source rock, only 13% of them in the reservoir. The amount of solid bitumen content, cracked gas and cracking gas resource are closely interrelated, and their distributing characters are the same with that of solid bitumen. Choosing a sound accumulation coefficient, the Lower Paleozoic cracking gas resource in Tadong is about （2.18-4.37） × 10^12m^3. That is to say, the exploration potential for natural gas is great in the Lower Paleozoic rocks in Tadong.