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Collaborating Authors
Boundary description and high-quality reservoir prediction of sublacustrine fan in Luda area of Bohai oilfield
Wei, Gao (Bohai Oil Research Institute, CNOOC China Limited, Tianjin Branch) | Hui-Huang, Tan (Bohai Oil Research Institute, CNOOC China Limited, Tianjin Branch) | Sheng-Qiang, Zhang (Bohai Oil Research Institute, CNOOC China Limited, Tianjin Branch) | Guang-Rui, Xiao (Bohai Oil Research Institute, CNOOC China Limited, Tianjin Branch)
Different from typical sublacustrine fan with “vermicular” reflection characteristics, it can be effectively described by conventional means such as coherence cube and multi- attribute clustering. Seismic reflection types are various, seismic response law is not clear, and main controlling factors of seismic reflection of sublacustrine fan are ambiguous in Luda area. And also, reservoir and non reservoir impedance are poorly differentiated, and reservoir physical properties change rapidly. So, many difficulties in sublacustrine fan reservoir evaluation and favorable zones forecast are presented. At the same time, sublacustrine fan in the study area is a lithologic reservoir in slope zone. The key to determine the size and shape of lithologic trap is to determine the up-dip pinch point of sand body, which is not obvious in seismic response. This article has carried out research on reflection characteristics and description of high-quality reservoirs: 1. Through petrophysical analysis, numerical simulation technology and phase decomposition technology, the seismic response mechanism is analyzed, and the seismic reflection mode of sublacustrine fan is clarified. 2. Prestack simultaneous inversion technology based on waveform feature constraint is proposed. The low-frequency prestack inversion model is improved by using effective waveform information of formation and lithologic structure, which reduces the dependence of conventional inversion methods on well logging and stratigraphic framework model. Thus, fine prediction and characterization of lithologic pinch out point of sublacustrine fan with sparse well pattern are realized. The research results have guided the exploration of LDX-2, the first pure lithologic well in slope zone with historical significance. This well creates the largest thickness of oil and gas reservoir for Paleogene lithologic exploration in Bohai oilfield, with high oil and gas production. The research results have provided guidance for the of the area oil evaluation, and promoted 7 wells to pass the risk review, which has an important reference for exploration of other sublacustrine fan lithologic reservoirs in Bohai area. Note: This paper was accepted into the Technical Program but will not be presented at IMAGE 2021 in Denver, Colorado.
- Asia > China (0.70)
- North America > United States > Colorado > Denver County > Denver (0.24)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling > Seismic Inversion (0.70)
- Geophysics > Seismic Surveying > Seismic Processing > Seismic Migration (0.47)
3D seismic description for sublacustrine fan of Paleogene Dongying Formation: A case study in Jinzhou a structure zone, northern Liaozhong subdepression
Gao, Wei (China National Offshore Oilfield Corporation (CNOOC) Ltd Tianjin Branch, Bohai Oilfield) | Tan, Hui-Huang (China National Offshore Oilfield Corporation (CNOOC) Ltd Tianjin Branch, Bohai Oilfield) | Jiang, Ben-Hou (China National Offshore Oilfield Corporation (CNOOC) Ltd Tianjin Branch, Bohai Oilfield) | Li, Yao (China National Offshore Oilfield Corporation (CNOOC) Ltd Tianjin Branch, Bohai Oilfield)
ABSTRACT 3D seismic description for sublacustrine fan of Paleogene Dongying formation in Jinzhou A structure zone, northern Liaozhong subdepression of Bohai Oilfield is studied. From formation mechanism, sublacustrine fan is classified by means of logging data and seismic data. With forward modeling and log-seismic method, seismic reflection characters and response mechanism are well studied. By analyzing logging response, seismic reflection and attributes, the authors study the sedimentary characteristics, and divide the sublacustrine fan into three subfacies. Utilization of coherence cube and the technique of multi-attributes fusion, lateral distribution and inter facies development zone of sublacustrine fan can be well-depicted. Research results predict favorable sublacustrine fan reservoir area of Dongying formation in Jinzhou A structure zone, which have a great significance to guide this type of lithologic reservoir exploration. Presentation Date: Tuesday, October 18, 2016 Start Time: 9:15:00 AM Location: 156 Presentation Type: ORAL
- Geology > Geological Subdiscipline (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.40)
Application of Geological Modeling Technique Based on Seismic Frequency Division Processing and Fluids Substitution Forward Modeling in Lithologic Gas Reservoir Risk Assessment
Liu, Zongbin (Tianjin Branch of CNOOC Ltd.) | Lv, Zuobin (Tianjin Branch of CNOOC Ltd.) | Wen, Jiatao (Tianjin Branch of CNOOC Ltd.) | Yan, Hao (Tianjin Branch of CNOOC Ltd.) | Yang, Zhicheng (Tianjin Branch of CNOOC Ltd.)
Abstract JZ Gasfield is an offshore sublacustrine fan lithologic gas field located in Bohai Bay Basin, in China, with a buried depth of about 1750m. It is currently in the stage of overall development plan preparation. Two exploration wells have been drilled. They show that the gas field has characteristics of rapid lateral change in reservoir, complex distribution range and connectivity of sand bodies. In addition, the few drilling data, large well spacing and low resolution of seismic data in the evaluation stage make it extremely challenging to establish an accurate geological model of gas reservoir. In order to solve the above problems, in this paper, an integrated geological modeling method based on seismic frequency division processing and fluid substitution forward modeling is proposed. There are four key aspects to this method. (1) Using seismic sedimentology, the lateral distribution ranges of sublacustrine fan sand bodies are described by seismic frequency division processing and interpretation technique and seismic variance attribute. (2) Based on markers of single-well, logging and seismic faceis, the average instantaneous frequency attribute is selected by optimizing the seismic attributes in the dominant frequency band, and then the distribution ranges of three subfacies including inner fan, middle fan and outer fan of the sublacustrine fan are characterized, and the fine sedimentary pattern of the sublacustrine fan is established. (3) Based on an understanding of the sedimentary pattern, fluid substitution forward modeling is carried out, and the superposition and connectivity of the sublacustrine fan sand body are described. (4) A 3D geological model of the sublacustrine fan sand body is established by using a new four-step modeling method including the concept of facies-in-facies modeling: 1) A model of the distribution of the sand body is established through a deterministic modeling method; 2) Within the sand body, according to the division results of subfacies, the distribution model of sub-facies is established; 3) A fine lithofacies model is established by combining stochastic simulation with deterministic modeling and hierarchical modeling from rough to fine under the constraint of a seismic attribute; 4) Petrophysical models are established by lithofacies control, which provide a more accurate geological model for preparation of the gas field development plan. Based on this comprehensive study, it is concluded that there is a great possibility of reservoir disconnection between the inner fan and the middle fan, where the gas reservoir is located, and the inner fan in the updip position of the structure has the risk of no gas accumulation, and the drilling risk in the development stage is greater than the potential. Based on this geological understanding, the available reserves of the gas field are reduced by nearly 40%.
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Fine characterization and reservoir prediction of the sublacustrine fan under facies constrain: A case study of Bohai Sea, China
Wang, Jun (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch, Tianjin, P.R.China) | Lv, Zhenyu (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch, Tianjin, P.R.China) | Liu, Teng (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch, Tianjin, P.R.China) | Li, Hong (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch, Tianjin, P.R.China) | Zhang, Jingsi (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch, Tianjin, P.R.China)
ABSTRACT Sub-lacustrine fan is gradually becoming a significant exploration field of lithological hydrocarbon reservoir as one of the lacustrine depositional systems, and breakthroughs from rift lacustrine basins have been made in recent years. The study area is located in the southern steep zone of Shijiutuo uplift of Bohai Sea. Based on a series of data including seismic data, well logging, etc. Sequence stratigraphic framework is established, which makes it clear that the sublacustrine fan is developed in the lower system tract of the second member of Dongying formation. and it is characterized by strong amplitude reflection and multi-stage deposition. Under the constraints of the sequence stratigraphic frame, six stage of the sublacustrine fan are recognized and three types of depositional elements could be identified, which include strong reflection stripe channel, strongly leaflike reflection of lobes, and weak reflection of leveeoverbank sediments. From early to late period, the sub-lacustrine fan overall moving from east to west horizontally. And has the characteristics of sedimentary evolution of early stage is lobe-thin layer, medium stage is channel-thin layer. On this basis, a sedimentary model of sub-lacustrine fan in this study area is established. Under the guidance of facies constrain, the reservoir prediction of sub-lacustrine fan was carried out qualitatively and semi-quantitatively, and the relationship between amplitude and thickness of sand body was established. At the same time, various geophysical techniques such as 3-D visualization, seismic spectrum decomposition, timefrequency analysis and multi-attribute fusion were used to characterize the reservoir of the sub-lacustrine fan. According to the prediction of hydrocarbon anomaly range in this area with pre-stack fluid detection factor, the results show that the hydrocarbon is very obvious and the exploration potential is great in the high tectonic area, especially in the sedimentary range of the channels. Presentation Date: Wednesday, October 17, 2018 Start Time: 9:20:00 AM Location: Poster Station 5 Presentation Type: Poster
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > China Government (0.30)
Sequence architecture and depositional evolution of Eocene to Oligocene, synrift to early postrift strata in the Baiyun Sag, South China Sea
Gao, Nanan (China University of Geosciences, Virginia Tech) | Lin, Changsong (China University of Geosciences, China University of Geosciences, Virginia Tech) | Eriksson, Kenneth (Virginia Tech) | Zhang, Zhongtao (Shenzhen Branch of CNOOC Ltd.) | Gao, Da (Yangtze University) | Zhang, Bo (Shenzhen Branch of CNOOC Ltd.) | Shu, Liangfeng (Shenzhen Branch of CNOOC Ltd.) | Wei, An (China University of Geosciences)
Abstract The Pearl River Mouth Basin (PRMB), located on the northern continental margin of the South China Sea, underwent a complex evolution during the Paleogene. We have focused on the Baiyun Sag in the PRMB with the goal of constructing the architecture and depositional evolution of the Eocene–Early Oligocene synrift stage to the Late Oligocene early postrift stage of basin evolution. Based on analysis of 3D seismic data complemented by well logs and cores, the Paleogene basin fills can be classified into three composite sequences bounded by regional unconformities and 14 sequences bounded by local unconformities. We identify seismic facies on the basis of different internal reflection configurations, external shapes, and contact relationships. The distribution of seismic facies and lithologies interpreted from gamma-ray curves reveal that the synrift basin fill consists mainly of fan delta deposits adjacent to the southern fault scarp, braid delta deposits on the adjacent hanging-wall blocks, and lacustrine mudstones and sublacustrine fan deposits in the center of the basin. The overlying early postrift stage is dominated by shelf and shelf-slope environments, with widespread developed southward-prograding deltas and submarine fans. Tectonics is the principal controlling factor on the development and distribution of depositional systems during the synrift stage. In contrast, sea-level changes superimposed on long-term subsidence related to thermal cooling determined the stacking patterns of sequences during the postrift stage. The results provide new insights on synrift and early postrift tectonics and sedimentation patterns along an evolving passive margin.
- Asia > China > South China Sea (0.35)
- Asia > China > Guangdong Province (0.30)
- Phanerozoic > Cenozoic > Paleogene > Eocene (1.00)
- Phanerozoic > Cenozoic > Paleogene > Oligocene > Upper Oligocene > Chattian (0.35)
- Phanerozoic > Cenozoic > Paleogene > Oligocene > Lower Oligocene > Rupelian (0.34)
- South America > Paraguay > Tarija Basin (0.99)
- South America > Bolivia > Tarija Basin (0.99)
- North America > United States > Wyoming > Uinta Basin (0.99)
- (15 more...)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Sedimentology (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Geologic modeling (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)