Comprehensive Study Of Accumulation Regularity In LuDong Sag Of Jiaolige Area

This paper makes a comprehensive research on the accumulation rule of Jiaolige depression area in Ludong area from four perspectives: structural interpretation,strata distribution,reservoir sedimentary characteristics and accumulative characteristics.A comprehensive structural interpretation aims to decide the bottom boundary structure of targeted section such as Jiufotang formation and Haisha formation etc in the area and know their structural characteristics(including fracture characteristics,trap distribution etc).The structure is relatively complex and the fracture is relatively mature.The Jiaolige area can be divided into northern slope belt,the central fractured belt,eastern slope belt,Jiaolige depression belt and Qinghe nose-shaped belt according to characteristics of fractures and stratigraphic development.The Ludong depression is mainly controlled by two huge fractures that stretches to east and northwest respectively,and it is also associated with numerous traps and the occlusion of fractures.Its has many structural activities,mainly explained by oil reservoir in fracture and traps which centered on structural traps.This paper firstly researches the strata distribution rule,then makes a further division of strata so as to identify the surface of the whole system.The knowledge of strata distribution is gained by establishing stratigraphic framework of three vertical and three horizontal in the whole industrial area.The researching areas have mainly two provenances: eastern slop belt and western Bianzhuang River delta and the area in the transitional area of marsh land with Sediments.Finally two sedimentary systems can be decided,they are near shore underwater fan in eastern slop belt and Bianzhuang River delta in western slop belt.Through the comprehensive research,it can be seen that the main controlling factors of oil are as follows: high point oil control in structure?the provenance controls in the oil direction and makes facies control meanwhile?the distribution feature of oil around marsh land.Final deployment proposal of well:deploy well jiao3?jiao44?guang9 at the top of the reservoir;deploy well jian20?jian21 around the stretched area of the original area.Through this study,the main results and recognition are as follows: 1 the research on the structure belt.This area is a southeastern fractured and northwestern covered depression,with the mature fracture in northwestern depression as depression axis.The Jiaolige area can be divided into northern slope belt,the central fractured belt,eastern slope belt,Jiaolige depression belt and Qinghe nose-shaped belt according to characteristics of its fractures and stratigraphic development.The depression in Ludong area is an uneven shape like waves,and the main exploration targeted section is the sediments in the fracture period.The fan delta,subaqueous fan and turbidite in the depression are mature,among which the subaqueous fan mainly grows on the steep belt southeast of fracture,the fan delta on the gentle belt northwest of fracture and turbidite near the drop plate in deep water area and fracture in the basin.2 Five sequences and two sub sequences are comprehensively divided in the research area.They are respectively upper Cretaceous system,Fuxin formation,Haisha formation,upper part of Jifotang formation and the bottom area of five set strata in the lower part of Jiufotang formation.3 There are mainly normal fracture from northeast to east and from northwest to west.They respectively control south margin of march land and distribution direction in fractured area and the eastern margin,which makes the drop plate in the fracture from northwest to west more complex.4 The depression in Ludong area are mainly controlled by two fractures and influenced by the extrusion of wrench fracture.Because of the intense structural activities,a series of traps are formed.The trap type in the research area are mainly centered on structural trap,and then strata trap and lithologic trap.5 The accumulation conditions are very complex in the research area.The oil reservoir is affected by complete structure and fracture so that the oil reservoirs are independently formed but fail to form a series of reservoirs.Therefore,in order to accumulate,it needs good accumulation conditions including structure and good reservoir,a good configuration relationship with hydrocarbon source rocks to make accumulation.6 The researching areas have mainly two provenances: eastern slop belt and western Bianzhuang River delta and the area in the transitional area of marsh land with Sediments.And the two sedimentary systems are near shore underwater fan in eastern slop belt and Bianzhuang River delta in western slop belt.7 it is advised to deploy well jiao3?jiao44?guang9 at the top of the reservoir;deploy well jian20?jian21 around the stretched area of the original area.