Reservoir Investigation Of Eopaleozoic Carbonate Buried Hill In Chezhen Zone, Jiyang Depression

Burried hills are now of great importance in the exploring field of oil and gas. And the research of buried hill reservoir is of great significance. In recent years,there have been great advancement on the exploration and development of buried hills in Jiyang Depression. This research will try to resolve the problem that build a predicting carbonate reservoir model by the study of the buried hill reservoir in Chezhen zone.In this research,according to the idea that analize the formation from single-well to multi-wells, the character of eopaleozoic burned hill reservoir is concluded, during the course of which the modern experiment and technical methods of reservoir investigation such as casting slice, cathodolu-minescence,inclusion,stable istope and neutrino activation are used.As the conclusions follow:1. The eopaleozoic carbonate formation of Chezhen Zone has a complex lithology, which includes dolomite,limestone,granule limestone,algal limestone,breccia,gypsum, etc, of which dolomite and limestone are the main kinds of litho- logy,and algal limestone is found locally.2.The eopaleozoic carbonate formation of burned hills in Chezhen Zone has five kinds of porosity,i.e. corroded pore, corroded cavity,cavem,and two types of fissures- fissure of weathering and tectoclase,of which the corroded cavity and the two types of fissures are the most important. And also five types of container rocks are decided: weathering fissure one, tectoclase one, corroded cavity one,fissure-cavity one,and corroded cavern one,of which the first three ones are the most important3.The diagenesis of the work area ,which mainly includes karst,dolomization and fracturing is of great complexity and of many types.In this research three stages of karst are recognized,which are the one that happened at the depositional stage and that was controlled by the declining of sea level,the one that happened in the end of Ordovician,and the one that happened in the end of Trias.4.The geochemistry analysis,together with the regional geology information,shows that the diagenesis solution of the main karst stage was mainly meteorological water, which was also warmedby the hot liquid of the formation water.Many geo-chemistry methods are used in this research,which includes inclusion analyzation,c-o stable isotope, trace element and rare earth element and try to explain the diagenesis solution and the origin of the rock.5. The distribution of reservoir are discussed and the conclusion is that the dolomite reservoir developed in Yeliliangjiashan-Fengshan Formation of the whole work area and that others,which are controlled by the faultage, rupture and lithology of the formation, developed around or in the middle of the work area.