含油气岩系中含铵矿物研究现状与前景

Current Situation and Development in Study on NH_4-bearing Minerals in Oil and Gas-bearing Rocks

研究表明 ,在含油气岩系中 ,当有机质发生热演变而成熟、并逐渐向烃类转变的整个过程中 ,氮主要以NH+4的形式释放出来而进入孔隙流体与周围介质 (成岩矿物 )相互作用 ,最重要的机制是NH+4可取代粘土矿物 (如伊利石 ,I/S混层矿物等 )层间的K+而参与成岩作用 ,形成含铵矿物 ,这一过程中氮的地球化学性质发生了重要变化 ,含铵矿物中固定 -NH4的富集状况与有机质成熟度及烃类运移有关。通过研究成岩和油气生成、运移、聚集过程中氮的岩石地球化学行为及其控制因素 ,可将固定 -NH4作为有机质成熟度和油气运移路径的一种新的。

Nitrogen,like carbon and oxygen,is one of important elements in Organic matter cor molecule In the oil and gas-bearing rocks, with the maturation and formation of into hydrocarbon from organic matters, nitrogen is released into pore fluids to form NH + 4 and interacts with diagenetic minerals(e.g.authigenic clay minerals). The most important mechanism that is NH + 4 substitutes for K + in interlayer sites of clay minerals (e.g. illite, ilite/smectite) and forms the NH 4-bearing minerals. The significant changes of the geochemical properties of nitrogen have taken place during the diagenetic process. The concentrations of fixed-NH 4 in the NH 4-bearing minerals is closely related to maturation of organic matter and migration of hydrocarbon. The fixed-NH 4 concentration of authigenic clay minerals increase gradually with the organic maturation. The diagenetic clay minerals along the hydrocarbon migration pathways were able to “catch” more NH + 4 during hydrocarbon migration and accumulation, and thus its fixed-NH 4 concentration is higher than other places.By means of many studies of the nitrogen lithogeochemisty and its influenced factors during diagenesis and hydrocarbon formation, migration as well as accumulaton, it shows that the new and potential use of fixed-NH 4 concentration as an indicator of organic maturity and hydrocarbon migration pathways.