The facies analysis of a fan delta by integrating multiple discipline data — A case study of the KL-A oilfield, Bohai Bay Basin, China

2020 ◽  
Vol 8 (2) ◽  
pp. SF21-SF35 ◽  
Author(s):  
Zhijun Yin ◽  
Bo Zhang ◽  
Yue Hu ◽  
Jianmin Zhu ◽  
Cheng Guo ◽  
...  
Keyword(s):  
Horizontal Distribution ◽  
Hydrocarbon Exploration ◽  
Well Logs ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Fine Grained ◽  
Facies Classification ◽  
Fan Delta ◽  
Mouth Bar ◽  
Rms Amplitude

The third member of the Shahejie Formation (Es3) is the main hydrocarbon exploration target in the KL-A oilfield, Bohai Bay Basin, East China. The facies classification is an essential step in mapping the depositional system of Es3 within the Bohai Bay Basin. The facies model is important for identifying the “sweet” lithology within the reservoirs. We characterize the facies of Es3 by integrating cores, well logs, and seismic data. The analysis indicates that the Es3 consists of fan delta deposits. The analysis using well logs and cores indicates that there are five different lithofacies for the Es3 Formation: massive sandstone, horizontally bedded sandstone, trough cross-bedded sandstone, ripple cross-laminated sandstone, and massive mud. The microfacies of Es3 include distributary channel, distributary mouth bar, interdistributary bay, and lacustrine mudstone deposits. The sweet lithologies for hydrocarbon accumulation within the KL-A oilfield include the coarse- and fine-grained sand developed within the channels and distributary mouth bar. We use seismic rms amplitude strata slices to determine the horizontal distribution of facies of the fan delta. The correlation between rms amplitude and well logs indicates that relatively low rms amplitude anomalies on the strata slices can be used as an indicator for sandstone within the KL-A oilfield.

Application of seismic sedimentology in lithostratigraphic trap exploration: A case study from Banqiao Sag, Bohai Bay Basin, China

2020 ◽  
Vol 8 (3) ◽  
pp. T501-T514
Author(s):  
Mingjun Su ◽  
Jun Yao ◽  
Qilin Chen ◽  
Kaifeng Hu ◽  
Zhong Hong
Keyword(s):  
High Resolution ◽  
Hydrocarbon Exploration ◽  
Seismic Facies ◽  
Lake Basin ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Fan Delta ◽  
Seismic Sedimentology ◽  
Fifth Order ◽  
Order Sequence

A method of identifying lithostratigraphic traps based on seismic sedimentology is proposed. We first establish a 3D high-resolution (fifth-order) sequence stratigraphic framework by using the stratal slices. Then, the reservoir distribution and reservoir-seal assemblage are investigated within the high-resolution sequence framework. This method turns the interpretation of lithostratigraphic traps from traditional seismic facies-based approach to the dynamic analysis of high-resolution seismic geomorphic information. We divide the lower Sha-1 member in the Banqiao Sag, Bohai Bay Basin, East China, into fourth- and fifth-order sequences by applying our method. The fifth-order sequence corresponding to Sha1-2 shows that the fan delta-distal subaqueous fan depositional system can be observed at the bottom of Sha1-2. The bounding fault and paleogeomorphology control the deposition of sand, whereas the sand bodies in the fan delta and distal subaqueous fan are developed near the bounding fault and the open lake basin, respectively. We then predict the sand thickness based on the well logs and seismic amplitudes. Moreover, according to the structural features, at least four lithostratigraphic traps are identified. These traps form a good reservoir-seal assemblage with overlying mudstones deposited during the period of lacustrine level rising. The drilling results in Trap-3 suggest that, our method can be a method of choice for effectively identifying the lithostratigraphic traps, a significant measure for hydrocarbon exploration.

scholarly journals The influences of sedimentary environments on organic matter enrichment in fine-grained rocks of the Paleogene Shahejie formation in Nanpu Sag, Huanghua Depression, Bohai Bay Basin

2021 ◽  
pp. 014459872110310
Author(s):  
Min Li ◽  
Xiongqi Pang ◽  
Guoyong Liu ◽  
Di Chen ◽  
Lingjian Meng ◽  
...  
Keyword(s):  
Organic Matter ◽  
Source Rocks ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Humid Climate ◽  
High Productivity ◽  
Fine Grained ◽  
Huanghua Depression ◽  
Shahejie Formation ◽  
Nanpu Sag

The fine-grained rocks in the Paleogene Shahejie Formation in Nanpu Sag, Huanghua Depression, Bohai Bay Basin, are extremely important source rocks. These Paleogene rocks are mainly subdivided into organic-rich black shale and gray mudstone. The average total organic carbon contents of the shale and mudstone are 11.5 wt.% and 8.4 wt.%, respectively. The average hydrocarbon (HC)-generating potentials (which is equal to the sum of free hydrocarbons (S1) and potential hydrocarbons (S2)) of the shale and mudstone are 39.3 mg HC/g rock and 28.5 mg HC/g rock, respectively, with mean vitrinite reflectance values of 0.82% and 0.81%, respectively. The higher abundance of organic matter in the shale than in the mudstone is due mainly to paleoenvironmental differences. The chemical index of alteration values and Na/Al ratios reveal a warm and humid climate during shale deposition and a cold and dry climate during mudstone deposition. The biologically derived Ba and Ba/Al ratios indicate high productivity in both the shale and mudstone, with relatively low productivity in the shale. The shale formed in fresh to brackish water, whereas the mudstone was deposited in fresh water, with the former having a higher salinity. Compared with the shale, the mudstone underwent higher detrital input, exhibiting higher Si/Al and Ti/Al ratios. Shale deposition was more dysoxic than mudstone deposition. The organic matter enrichment of the shale sediments was controlled mainly by reducing conditions followed by moderate-to-high productivity, which was promoted by a warm and humid climate and salinity stratification. The organic matter enrichment of the mudstone was less than that of the shale and was controlled by relatively oxic conditions.

scholarly journals A Study on Astronomical Cycle Identification and Environmental Response Characteristics of Lacustrine Deep-Water Fine-Grained Sedimentary Rocks: A Case Study of the Lower Submember of Member 3 of Shahejie Formation in Well Fanye-1 of Dongying Sag, Bohai Bay Basin, China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Ledan Yu ◽  
Jun Peng ◽  
Tianyu Xu ◽  
Yubin Wang ◽  
Haodong Han
Keyword(s):  
Sedimentary Rocks ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Fine Grained ◽  
Dongying Sag ◽  
Response Characteristics ◽  
Milankovitch Cycle ◽  
Study Interval ◽  
Shahejie Formation ◽  
Rock Strata

With the further exploration and development of shale oil and gas, cycle division of fine-grained sedimentary rock strata has been increasingly highly focused on by scholars. Owing to the application of the theory of classical sequence stratigraphy based on water depth changes and its technical methods being unsatisfactory in the isochronous division and correlation of deep-water fine-grained sedimentary strata, the cycle division of fine-grained sedimentary rock strata has always been a difficult point in the study of sequence stratigraphy. In this paper, the Milankovitch cycle recorded from the study interval and the environment response characteristics were studied, with the lacustrine shale in the lower third submember of the Paleogene Shahejie Formation (lower Es3 submember) in Well Fanye-1 of the Dongying sag, Bohai Bay Basin, as the object of study, by such technical means as thin section identification and X-ray whole rock diffraction, based on such data as logging data and geochemistry, combining the methods of spectral analysis, wavelet transform, and modulus extremum. The results showed that the stratigraphic cycle thicknesses caused by long eccentricity, short eccentricity, and obliquity periods were 38.95 m, 12.98 m, and 4.10 m, respectively, and a total of 16 short eccentricity periods and 4.5 long eccentricity periods were identified in the study interval. Thus, it was further calculated that the sedimentation time was approximately 1.905 Ma, and the average sedimentation rate was estimated to be 0.105 m/ka. Studies have shown that the sedimentary environment of lacustrine fine-grained sedimentary rocks is controlled by the astronomical period, based on which the climate as a whole changes from relatively dry and cold to warm and wet when the eccentricity increases. The identification of the Milankovitch cycle of the lacustrine fine-grained sedimentary strata will provide references for the study of high frequency sequence and the division of high-resolution sequence strata, which can effectively solve the scientifically difficult isochronous division and correlation of lacustrine shale strata.

Reservoir Modeling of Fan Delta with Sparse Wells: A Case from CFD Oilfield in Shijiutuo Uplift, Bohai Bay Basin

2019 ◽  
Author(s):  
Xiaoming Ye ◽  
Pengfei Wang ◽  
Junfei Li ◽  
Jianmin Yang ◽  
Feifei Miao ◽  
...  
Keyword(s):  
Reservoir Modeling ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Fan Delta

The Depositional System of Dongying Formation and Subtle Reservoir Exploration in Sha’nan Structural Belt Qikou Sag of Bohai Bay Basin, China

2012 ◽  
Vol 616-618 ◽  
pp. 32-37
Author(s):  
Ren Li Qi ◽  
Kai Yuan Chen ◽  
Bo Niu ◽  
Zhan Tao Xing
Keyword(s):  
Analysis Data ◽  
Hydrocarbon Exploration ◽  
Seismic Facies ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Hydrocarbon Source Rock ◽  
Offshore Area ◽  
Qikou Sag ◽  
Sand Bar ◽  
Geological Analysis

The subtle reservoir has become an important exploration target within the Bohai Bay Basin, especially in the Qikou sag. In order to guide subtle reservoirs exploration in offshore area geological analysis to Sha’nan structural belt is carried out in this paper. Qikou sag has large thickness, high abundance, ideal type hydrocarbon source rock. By unconformity recognition technique and paleotectonic analysis technique, results show that tectonic uplift had provided sedimentary source to the depression around it after Es1. By 3-D seismic interpretation technique and Seismic facies analysis, the sedimentary facies was confirmed. Geological analysis results show that sand bar, subaqueous fan is developed around it in Ed3. With the new geological analysis data sedimentary model of Sha’nan structural belt has been built in this paper. The sand bar and subaqueous fans showed a good reservoir potential, which are advantageous to oil accumulations. The southern part of Sha’nan structural belt has good hydrocarbon exploration potential.

Three-dimensional forward stratigraphic modelling of the gravel-to mud-rich fan-delta in the slope system of Zhanhua Sag, Bohai Bay Basin, China

2017 ◽  
Vol 79 ◽  
pp. 18-30 ◽  
Author(s):  
Qianghu Liu ◽  
Xiaomin Zhu ◽  
Hongtao Zhu ◽  
Keyu Liu ◽  
Mingxuan Tan ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Fan Delta ◽  
Slope System
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