The Research On Reservoir Sedimentary Character And Predicting Favorable Target In Fuwan-zhangchang Area Of Biyang Depression

The Fuwan-Zhangchang aea is located at the northwest of Biyang depression with 120 square metres, on the east is Yanglou oil field and on the west is Gucheng oil field. It's a nose structure and the northeast is the main aligement of its faults. The traditional opinion is that there isn't favorable reservoir condition, but in the 70 wells up to now, most of the wells have some display of oil, and in few of wells come to oil in the well testing. The oil layer is drilled in the wells of Fuqian2,Fuqian5,Fuqian7,Fuqianl9,Biqianl4, so there are some fault-lithology traps or fault-block traps probably. The immature oil and the oil generated from the southern deep area provide some condition of oil resources, and the researched area has some hydrocarbon accumulation conditions. But there are some problems for example the material source,the sandbody distribution,the controlling factors are unknown, these take great difficulty to the next exploration.Through detailed core description to make definite sedimentary facies and microfacese, guided by high resolution sequence stratigraphy and recent sedimentology, this paper completes the sublayer's division and correlation,distributive character of sand well tie profile and plane combining the trap type,the control factors,the regularities of hydrocarbon accumulation and analysis of oil reservoir profile, predictes favorable target.There are main results and understands as follows:1, Comprehensing drilling,logging and seismic information, under the guidance of the high resolution sequence stratigraphy theory, complete the sublayer's division and correlation of the wells in this area. Every oil group can be divides into a medium term cycle composed by a ascending hemicycleand a descending hemicycle. Under the control of medium term cycle, based on the cycle of logging curve and lithologic association, theⅣ,Ⅴ,Ⅵoil groups can be divided 7,5,5 sublayers respectively.2,Through the detailed core observation of these wells of the wells of Fuqian2,Fuqian5,Fuqian7,Fuqian19,Biqian14, the types of petrologic phase have 14 types, the mains are parallel bedding fine sandstone phase,the hummocky cross-stratification silt phase,the mixed bedding fine sandstone phase,the mixed bedding silt phase, horizontal bedding silt phase,mudstone and shale.3,Based on detailed core description and the plane of sand body, think that this research area belongs to delta deposit and shore and meare deposit. The delta deposit is further divided into delta distributary channel,sand sheet and mouth bar; the shore and meare deposit is further divided into beach,dam.4,Through the research on the corresponding relationship of the core phase and the logging curve, establish the plate that can transform geologic facies to electrofacies, and apply to recognize the sedimentary microfacies of the non-coring wells.5,Utilizing high resolution sequence stratigraphy theory, analyse the sand body distribution regularity of the 5 well tie profile. The thickness of sand body is gradual decreasing from the shallow to the deep.the thickness near the bi137 well and bi145 well is major relatively since the effection of three material sources. the thickness of The IV oil group is higher than the V oil group and the VI oil group, theⅥoil group is second. The general trend is gradual decreasing from the bottom to the top in theⅣoil group. The main sediments in the VI oil group are mud stone and shale since the increasing lake plane immediately.6,Based on the the core description,grain,heavy mineral information,plane of sand body and so on, conclude that there are three direction of material, particularly, the northwest is Yanglou delta, the north is Fuwan delta and the southwest is Gucheng delta, and the depositional model is established.7,Combining other's research paper,the main trap types of oil are the fault nose trap,the fault block trap and the fault-lithology trap. The oil generated from the southern deep area and migrated by sand body and fault is accumulatd in the favorable area. The distributary channel is the best sedimentary microface that accumulates oil, the second is sand sheet.8,Based on the how of oil and gas, combining the favorable area of the plane of sand body,distribution of sedimentary facies,structure character,the regularities of hydrocarbon accumulation and so on, conclude that the trap of oil is controlled by sedimentary and structure. The favorable areas distribute in the middle southern area, the southwest, and the eastern. The northern oiliness is not good since the sand body of Fuwan delta extends relative short and is damaged by the uplifted structure on the liaozhuang period.9,Predict two favorable target in the the favorable area and provide the concrete weill location. The first that could exist nipped sand trap or fault-lithology trap is between the bi145 weill and the bi137 well,the second that could exist fault-lithology trap or lentic trap is between the bi15 well and the bi397 well.