| Guan 15-2 block is in Wangguantun, county of Cangxian, Hebei Province. Its regional tectonic zone located in the west and the southern end of tilt of Kongdong fault of Kongdian tectonic belt and in the uplifted side of Kongdong Fault, which is in the south part of Huanghua depression. The block is a step construction attached to Kongdong Fault, which is under the control of it. The formations of the block uplift and become flat along the North East. The main development strata are Zaoâ…¡oil group of the First Member of Kongdian Formation and Sha 3 oil group of the Third Member of Shahejie Formation.This thesis targeted the Guan 15-2 block at Wangguantun and took Zaoâ…¡oil group of the First Member of Kongdian Formation as research object. Some theories and technologies such as Sedimentology, high resolution sequence stratigraphy, mineral petrology, Geophysics, Petroleum Geology were applied as well as a plenty data of drill core, well drilling, bore log and seism. Depend on the former research and a core of"high resolution sequence stratigraphy—depositional system—lithofacies paleographic—study of single sand body", the sedimentary facie characters of Zaoâ…¡oil group of the First Member of Kongdian Formation in Guan 15-2 block were systematic researched.First, this study is based on previous work carried out regional geological studies. Then, as sequence stratigraphy of continental a starting point, after study of sequence stratigraphy for Zaoâ…¡oil group of Kong-1 Member, high-resolution sequence stratigraphic equitime framework was made. Under the framework, sedimentary facies, subfacies, microfacies types and their changes were analyzed to clear distribution of depositional systems and establish depositional model. Thirdly, study of characteristics of single sand body including fine classification and correlation of single sand bodys, sedimentary facies and characterization of microstructure morphology of top boundary of single sand bodys of them. Some results and new cognitions came out as below: 1) Theories and methods of high resolution sequence stratigraphy which took Cross base-level cycles as guiding ideology were integrated with the data of seism, drill core, well drilling and bore log. The Zaoâ…¡oil group of the First Member of Kongdian Formation in Guan 15-2 block was analyzed by a detailed high resolution sequence stratigraphy and classified by one middle-long-period cycle sequence (MSCZ1). Based on the existed stratigraphy subdivision methods of the First Member of Kongdian Formation in Guan 15-2 block, the high resolution sequence stratigraphic features and structures of target area were systematically studied and a high resolution sequence strata framework was found with long-period cycle units.2) Combining the sedimentary facie marks and previous research results, a systematic sedimentary facie division was done at Zaoâ…¡oil group of the First Member of Kongdian Formation in Guan 15-2 block. Three sedimentary facies of lake delta and sublacustrine fan were classified. Every sedimentary facies could be divided into different sub-facies and micro-facies. A sedimentary pattern which accorded with the local geological conditions of study area was modeled.3) Depends on the main mapping units with middle-long-period cycle, three sequence-lithofacies paleographic maps with one middle-long-period cycle sequence (MSCZ1)were compiled respectively. Overall, the study area is lake delta duing the time of Zaoâ…¡oil group of the First Member of Kongdian Formation, that is to say, delta facies. The the study area is smaller, so the study area are only developed delta front deposition, mainly developed distributary channel, split between the Bay mouth bar, distal bar sedimentary microfacies, which are distributed in the study area. In addition, the study area is debris-type lakes. The study area mainly developed in the lake system of shore - shallow lake area, locally semi-deep lake up - deep lake. Sublacustrine fan (turbidite fan) phase are mainly developed in the study area.Delta front facies are there in the MSCZ1. Micro-phase are mainly underwater distributary channel and mouth bar, followed by the distal bar facies. In MSCZ1 period, the main sedimentary facies evolution of underwater distributary channelâ†'mouth barâ†'distal bar, reflecting a lake transgressive process.4) With multi-level contrast reservoir principle, comparing the deposition time unit, 8 sets of single sand body are divided. Three longitudinal sections of 11 wells in the First Member of Palaeogene Kongdian Formation in Guan 15-2 Block had been made, and single sand bodys had been contrasted.5) With single sand body of sequence - sedimentary facies and sand body distribution maps, sedimentary facies of single sand bodys had been divided based on refinement of partition and comparison of 8 sets of single sand body, and 8 maps are made. Three longitudinal sections of 11 wells in the First Member of Palaeogene Kongdian Formation in Guan 15-2 Block had been made, and sedimentary facies of single sand bodys had been contrasted.6) With single sand body of sequence - sedimentary facies and sand body distribution maps, 8 sets of single sand body structure are clear and 8 maps are made.7) Through this study, based on the correlation and classification of equitime deposition time unit, high-resolution sequence stratigraphic framework had been built. And under the control of the medium-term cycles, fine deposition model had been created. Detailed and accurate analysis and characterization of microstructure morphology of top boundary of single sand bodys was made. The research for the next work including foundation of three-dimensional geological model of reservoir, reserves re-count, reservoir heterogeneity research and prediction of favorable reservoir, provides a reliablegeological evidence. At the same time, this study will provide effective guidance for the oil field research and production of future work. |
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