| Junggar basin, one of large oil and gas basins in China northwest. Major tectonic units in China-part of the Junggar block. The Tianshan orogenic belt, East and westJunggar and Altai mountains surrounded the Hercynian fold. An area of130,900square kilometers. Above Junggar Triassic basin is Mesozoic and Cenozoic unified continental sedimentary basins. Composite overlay with the underlying Paleozoic Partition of Sea-land transition of sedimentary basins, therefore, This is a large composite superimposed basin.Zhong18Wells block in Feng cheng oilfield is located in the northwestern margin of junggar basin north Feng cheng oilfields in western city, about120km from karamay city, north Zhong32Wellblock, south neighbouring uzbekistan33wellblock and bituminous, west Wuerhe township, east into the Zhong43wellblock, administrative part of karamay. And on regional tectonic in wuxia fault fold belt of xia hong on the plate north Fracture on Mesozoic overlap pinchout belt, north is bounded with hala Allah mountain, south slope zone in the north of lake sag, reservoir updip and downdip direction were cut fault, wuxia fault fold zone of slip type fold-related to frontal fault anticline belt structure model. Due to prolonged high tectonic area, and connected to reservoir and oil source faults, oil and gas migration is the main point to area. Connected to reservoir and oil source faults and are favorable for oil and gas gathering area.In the heavy oil reservoir is formed in the long geologic process, early damage to reservoir, oil and gas migration along the grams, wu rupture occurred many times, up to the plate on the nappe overlap pinchout with secondary reservoir formation, then through light component loss, water oxidation, and severe biodegradation, the resulting heavy oil reservoir.Feng cheng oilfield is located in wuxia fault fold belt of xia hong north rupture disc on Mesozoic overlap pinchout belt, Wuxia fault fold zone of slip type fold-related to frontal fault anticline belt structure model, By the influence of the the front two concealed fault in Permian, the influence of basement inner concave and convex alternate arrangement, buried depth to the south east direction. Wuxia fault belt has experienced since the end of the carboniferous late hercynian, indosinian movement, yanshan movement of the inheritance and development, the late yanshan end cover.Middle yanshan movement, in the regional tectonic activity intensity from carboniferous-Permian declined substantially, to fill the demise of intracontinental depression period, but still have inheritance activities in wuxia fault belt, eastern piedmont thrust activity is stronger. Early early Jurassic, middle Jurassic, the northwest edge in a quiet period of tectonic activity, with hala Allah in northern shandong pour part still in high relief, in the steady sinking, in the original imbricated thrust wedge on the sedimentation of the stability of roof wedge, overlap characteristics;In late Jurassic in nearly east-west stretch environment; At the end of Jurassic, with the basin, a regional tectonic activity, wuxia fault belt in the north of nappe zone fracture activation again, resulting in slope area outside the fold area relative uplift, and the Jura suffered different degree of denudation.Jurassic sedimentary period settlement center is mainly located in the Feng cheng of eastern region and Xia Zi street, from wet to semi-arid climate change, the development of the Jurassic in the Badaowan formation、the coal measures hydrocarbon source rocks of Xi shanyao formation and three river lacustrine argillaceous source rocks. Sedimentary experienced alluvial fan, braided river, braided plains, delta, fan delta, lacustrine deposition process, most of the region are coarse debris cover, large conglomerate mainly appear in the Feng cheng, Xia Zi street area.Cretaceous period, weak tectonic activity, namely the late yanshan basin edge uplift, denudation, basin in relative decline, in addition to the work area in the northwest of the o’hara Allah mountain subject still have activity external-stress-arch, wuxia fault belt area main fracture and fold ground to a halt, tectonic movement is mainly characterized by intermittent settlement activity, the cretaceous and Cenozoic strata later smooth filling, from southeast to northwest, in turn, low Angle overlap sedimentary in ancient tectonic background, thin and thick strata of south north gradually thin out, still retains the level attitude.Badaowan layer of Jurassic in Zhong18well block and overlying strata of Jurassic in conformable contact three days river group.with the unconformity of the Permian of the underlying strata under the conditions of the contact, contact clearly:Badaowan layer of Jurassic in zhong18well block is divided into J1b1、J1b2+3J1b4'J1b5; Badaowan strata in zhong18well area of FengCheng oil field is South-dipping monocline, The thicker area is from northeast to southwest and banded distribution.According to the characteristics of stable heavy mineral assemblages (ZTR) and the distribution of the ratio of the sandstone and stratigraphic and the ratio of the conglomerate and stratigraphic,identify Badaowan formation sediments source comes from the north-west.In this paper, on the basis of predecessors’research, analysis of coring well core observation, and the logging, logging and testing data for research analysis, think that the study area is a set of braided river-and alluvial fan sedimentary bodies with river and braided river sedimentary development river flood2subfacies and river stranded, diara, flood land, such as swamp microfacies.Established the control of single well facies, the sedimentary section connected well, recognize the purpose layer in all directions in the study area of sedimentary facies, subfacies and microfacies distribution characteristics, at the same time, draw on each small layer plane distribution of sedimentary microfacies are layout, showing the regional features of sedimentary facies.Badaowan formation belongs to the braided river, alluvial fan sedimentary system, Badaowan formation J1b5belongs to the alluvial fan deposit, the development of lithologic coarser, mainly composed of glutenite, development channel deposits and sheetflood deposits. J1b4for river stranded at the bottom of the sedimentary cover on the Permian system of gravel rock mass directly, because the source supply is limited, J1b4top water power weakened quickly, granularity, tapering from the bottom of the large development of glutenite, it gradually transition to the sandstone lithofacies, small thin layers of mudstone layer top or argillaceous sandstone facies, is for a complete cycle mode, with the actual research of sedimentary facies, and the small layer has the transition to bed deposition of braided river facies, warm and humid climate, lush plants, forming a set of, thin layer of gray, celadon siltstone with black carbonaceous shale, coal line of individual well development also belongs to the swamp system. J1b2+3times, deposited a set of conglomeratic sandstone and sandstone, belonging to the braided river channel microfacies, stranded and beach water energy is abate, gradually transition to the river flood subfacies. Late eight bay group (J1b1), reaching gently, warm and humid climate and terrain provenance supply decrease, the overall mainly mudstone, argillaceous sandstone lithofacies, reflect the overall transition has to braided river river flood subfacies... |
PDF Full Text Request