胜利油区下古生界岩石地层鉴别特征

Identification feature of strata in lower Paleozoic erathem in Shengli petroliferous area.

胜利油区下古生界有广泛的分布 ,其岩石缝、洞发育 ,并储集有丰富的石油资源 ,是油田勘探的重要目的层之一。为了提高地质录井过程中对下古生界岩石地层的鉴别精度 ,在充分应用宏观及微观资料的基础上 ,研究了胜利油区及邻区层型剖面下寒武系及奥陶系岩石地层特征 ,认为岩石地层方法在大量的地层划分对比中具有快速、准确而实用的优势。根据地层对比的需要 ,提出了应用硬石膏分布状态、结晶形态、伴生矿物等特征进行含膏岩石地层判定 ;应用结晶白云岩的结晶程度、白云石自形程度、燧石含量等的差异性质确定其层位归属 ;根据鲕粒灰岩的鲕粒大小、重结晶程度。

Lower Paleozoic of Shengli petroliferous area is one of the important target strata in the oilfield exploration with wide distribution, developed rock fractures and caves and being rich in petroleum resources. In order to improve the precision of identifying the formations of lower Paleozoic rocks during geological logging, formation features of lower Cambrian and Ordovician system rocks are studied under stratotype profile in Shengli petroliferous area and neighbouring areas on the basis of full use of macroscopic and microscopic data. It is considered that rockformation method has the quick, accurate and practical advantages among a lot of stratigraphic classification and correlation. According to the need of the stratigraphic correlation, several working methods on petrostratigraphy are put forward, that is, using the features of distribution pattern, crystal morpha and accompanying mineral etc. of anhedritite to determine gypsiferous formation; using the difference in crystal degree of crystal dolomite, automorphic extent of dolomite and chert content etc. to determine the horizons′ ownership; according to the size of oolith, recrystallization degree and metasomasis of oolitic limestone to classify strata.