Structural Features Controls of Coalbed Methane (CBM) Accumulation in the Weibei CBM Field, Southeastern Ordos Basin

2014 ◽  
Vol 962-965 ◽  
pp. 79-82 ◽  
Author(s):  
Ya Dong Bai ◽  
Tao Tao Yan ◽  
Jian Guo Wu ◽  
Yong Luo
Keyword(s):  
Theoretical Analysis ◽  
Seismic Data ◽  
Coalbed Methane ◽  
Ordos Basin ◽  
Structural Features ◽  
Gas Content ◽  
Normal Faults ◽  
Distribution Characteristics ◽  
Structural Interpretation ◽  
High Consistency

Based on the structural interpretation of seismic data, we analyzed the gas controlling effects of folds and faults on CBM accumulation qualitatively. Meanwhile, we discussed the lateral sealing ability of the major overthrust faults quantificationally by bringing in “Shale Gouge Ratio (SGR)”, which is proved to be applicable in analyzing the gas controlling effects of faults. The results of the theoretical analysis show that overthrust faults have better sealing effects than normal faults, and synclines are more conducive to CBM accumulation than anticlines. The SGR computed results show a high consistency with the distribution characteristics of the CBM gas content. In all, the folds have little controlling on CBM accumulation, and the faults play a major role in the gas controlling on CBM accumulation in the Weibei CBM field.

Structure of giant buried mud volcanoes in the South Caspian Basin: Enhanced seismic image and field gravity data by using normalized full gradient method

2018 ◽  
Vol 6 (4) ◽  
pp. T861-T872
Author(s):  
Mehrdad Soleimani ◽  
Hamid Aghajani ◽  
Saeed Heydari-Nejad
Keyword(s):  
Seismic Data ◽  
Root Zone ◽  
Gravity Data ◽  
Complex Structure ◽  
Normal Faults ◽  
Mud Volcanoes ◽  
South Caspian Basin ◽  
Structural Interpretation ◽  
Seismic Image ◽  
Normalized Full Gradient

Defining the root zone of mud volcanoes (MVs), structural interpretation, and geologic modeling of their body is a problematic task when only seismic data are available. We have developed a strategy for integration of gravity and seismic data for better structural interpretation. Our strategy uses the concept of the normalized full gradient (NFG) for integration of gravity and seismic data to define geometry and the root zone of MVs in the southeast onshore of the Caspian Sea. Our strategy will increase the resolution of the seismic envelope compared with the conventional Hilbert transform. Prior to interpretation, we applied the NFG method on field gravity data. First, we perform a forward-modeling step for accurate NFG parameter definition. Second, we estimate the depth of the target, which is the root zone of the MV here. Interpretation of field gravity data by optimized NFG parameters indicates an accurate depth of the root zone. Subsequently, we apply the NFG method with optimized parameters on a 2D seismic data. Application of our strategy on seismic data will enhance resolution of the seismic image. The depth of the root zone and the geometry of the MV and mud flows was interpreted better on the enhanced image. It also illustrates the complex structure of a giant buried MV, which was not well-interpreted on conventional seismic image. Interpretation of the processed data reveals that the giant MV had lost its connection to its reservoir, whereas the other MV is still connected to the mud reservoir. The giant MV is composed of complex bodies due to pulses in the mud flows. Another MV in the section indicates narrow neck with anticline and listric normal faults on its top. Thus, application of the NFG concept on seismic image could be considered as an alternative to obtain enhanced seismic image for geologic interpretation.

Multicomponent 3-D characterization of a coalbed methane reservoir

Geophysics ◽  
1996 ◽  
Vol 61 (2) ◽  
pp. 315-330 ◽  
Author(s):  
Edward L. Shuck ◽  
Thomas L. Davis ◽  
Robert D. Benson
Keyword(s):  
Shear Wave ◽  
Seismic Data ◽  
Coalbed Methane ◽  
Accurate Determination ◽  
P Wave ◽  
Seismic Survey ◽  
Fracture Density ◽  
Structural Interpretation ◽  
Coalbed Methane Reservoir

Methane is produced from fractured coalbed reservoirs at Cedar Hill Field in the San Juan Basin. Fracturing and local stress are critical to production because of the absence of matrix permeability in the coals. Knowledge of the direction of open fractures, the degree of fracturing, reservoir pressure, and compartmentalization is required to understand the flow of fluids through the reservoir. A multicomponent 3-D seismic survey was acquired to aid in coalbed methane reservoir characterization. Coalbed reservoir heterogeneities, including isolated pressure cells, zones of increased fracture density, and variable fracture directions, have been interpreted through the analysis of the multicomponent data and integration with petrophysical and reservoir engineering studies. Strike‐slip faults, which compartmentalize the reservoir, have been identified by structural interpretation of the 3-D P‐wave seismic data. These faults form boundaries for pressure cells that have been identified by P‐wave reflection amplitude anomalies. The analysis of polarizations, traveltimes, and reflection amplitudes from the shear‐wave seismic data has allowed the identification of zones of variable fracture direction and fracture density. There is good agreement between stresses inferred from the structural interpretation and those indicated by the shear‐wave polarizations. Reflection amplitudes have been calibrated to seismic velocities and reservoir pressures through the use of petrophysical data taken from core samples. New methods have been developed for the statistical analysis of prestack shear‐wave polarizations, poststack polarizations, and the accurate determination of traveltime anisotropy. The prestack polarization analysis method allows for rapid and efficient determination of a dominant polarization direction. Shear‐wave anisotropy has been quantified over the reservoir zone using both traveltime and thin‐bed reflection response with excellent agreement between the two methods. Crack densities computed from the anisotropy show two regions of high crack density, one coinciding with a sealed overpressured cell and the other in the region of the Hamilton ♯3 well. This indicates the potential for monitoring production of coalbed methane reservoirs using multicomponent seismology.

scholarly journals Coalbed Methane Potential Evaluation and Development Sweet Spot Prediction Based on the Analysis of Development Geological Conditions in Yangjiapo Block, Eastern Ordos Basin, China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xinyu Fu ◽  
Yanjun Meng ◽  
Zhongcheng Li ◽  
Peng Kong ◽  
Suoliang Chang ◽  
...  
Keyword(s):  
Water Level ◽  
Coalbed Methane ◽  
Evaluation Method ◽  
Ordos Basin ◽  
Gas Content ◽  
Fuzzy Evaluation ◽  
Sweet Spot ◽  
Southeastern Part ◽  
Geological Conditions ◽  
Reduced Water

The evaluation and prediction of favorable coalbed methane (CBM) sweet spot play an important role in well location deployment and recovery prediction in CBM blocks. This work investigates the CBM geology and accumulation characteristics of No. ( 8 + 9 ) coal in the Carboniferous Taiyuan Formation in Yangjiapo block based on data from 14 CBM wells. The desorption index is proposed to be used to study the CBM desorption potential in Yangjiapo block, and the parameter of reduced water level is adopted to study the CBM hydrodynamics of the block. Furthermore, the analytical hierarchy fuzzy evaluation method is used to evaluate and prediction the CBM development sweet spot in Yangjiapo block. The results show that the buried depth of the No. ( 8 + 9 ) coal seam in Yangjiapo block varies from 693.20 to 1213.20 m, the coal thickness is from 5.40 to 13.10 m, the gas content is from 5.89 to 10.55 m3/t, and the minimum horizontal principal stress is from 9.80 to 20.82 MPa. The desorption potential is better in the southeastern and central-western part of the block. It is found that there is a positive relationship between CBM content and hydrodynamics and indicated that CBM easily concentrates in the lower reduced water level area. The CBM favorable development sweet spot is forecasted to be located in the southeastern part, central-western region, and northeastern part of Yangjiapo block.

scholarly journals Productivity subarea of CBM field and its key controlling factors: A case study in the Hancheng pilot test area, southeastern Ordos Basin, China

2018 ◽  
Vol 37 (1) ◽  
pp. 102-124 ◽  
Author(s):  
Yanfei Liu ◽  
Dazhen Tang ◽  
Song Li ◽  
Hao Xu ◽  
Shu Tao ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Ordos Basin ◽  
Gas Production ◽  
Test Area ◽  
Gas Content ◽  
Pilot Test ◽  
Coal Seams ◽  
Geological Factors ◽  
Drop Rate

The Hancheng block in the southeastern Ordos Basin is one of the earliest and the most important areas for coalbed methane exploration and development in China. However, there are significant production variations in different wells or even some adjacent wells in the Hancheng block. To reveal the reasons of production differences in such a small scale, further detailed studies of coalbed methane productivity in the Hancheng pilot test area, a precursor trial area in Hancheng block with mature, well-characterized coalbed methane reservoirs and long-term production database, were conducted. The influence of nine factors (including engineering and geological factors) on gas production was analyzed. By introducing the rough set theory, which is applicable to the vague, imprecise, and incomplete information system, this paper presents a method for quantitative evaluation of the influencing factors on gas production. The results indicate that there are certain distribution characteristics of productivity in Hancheng pilot test area, which can be partitioned into four zones. The degressive order of the influencing degree of these nine factors is (i) the distance between the well and the fault, (ii) the structure curvature of the coal seams, (iii) the gas content, (iv) the critical reservoir ratio, (v) the volume of the fracturing liquids per meter, (vi) the volume of the fracturing sand per meter, (vii) the dynamic liquid level drop rate, (viii) the depth, and (ix) the thickness. Geological factors, especially the influence of fault, structural curvature of the coal seams and gas content, play a major role in controlling long-term gas production. Engineering factors (effect of fracturing and dynamic liquid level drop rate) have always been integral parts of coalbed methane development.

Evaluation of the Gas Content of Coal Reservoirs with Geophysical Logging in Weibei Coalbed Methane Field, Southeastern Ordos Basin, China

2013 ◽  
Vol 734-737 ◽  
pp. 331-334
Author(s):  
Tao Tao Yan ◽  
Zhi Qiang Liu ◽  
Li Ren Xing ◽  
Yong Luo ◽  
Ya Dong Bai ◽  
...  
Keyword(s):  
Coalbed Methane ◽  
Gamma Ray ◽  
Ordos Basin ◽  
Measured Data ◽  
Gas Content ◽  
Burial Depth ◽  
Geophysical Logging ◽  
Natural Gamma ◽  
Geophysical Logs ◽  
Movement Intensity

Gas content is one of the most important factors in the process of exploration and development of coalbed methane (CBM). The relationships between gas content and characteristics of geophysical logs have been evaluated for the No. 5 coal seam in Weibei CBM field. It is found that the main well loggings that have good responses for gas contents are the compensating density, natural gamma-ray, compensating neutron, natural spontaneous potential and acoustic. A theoretical model was proposed to calculate the gas content by using these well logging data and as well as the burial depth. The calculated gas contents fits well with the measured data with a small relative-error of 0.38-5.05%. In the model, both tectonic movement intensity and the gas accumulation were taken into consideration. Key words: Coalbed methane, Weibei coalfield, Ordos Basin, Gas content, Geophysical logging

Global Mapping and Analysis of the Structural Features in the Northern Smooth Plains of Mercury

2021 ◽  
Author(s):  
marco cardinale ◽  
Gaetano Di Achille ◽  
David A.Vaz
Keyword(s):  
Imaging System ◽  
Structural Features ◽  
Planetary Science ◽  
Altimeter Data ◽  
Normal Faults ◽  
Laser Altimeter ◽  
Volcanic Material ◽  
Geological Map ◽  
Dual Imaging

<p>Orbital data from the Messenger spacecraft (1) reveal that part of the Mercury surface is covered by smooth plains, which are interpreted to be flood volcanic material across the planetary surface (2). In this work, we present a detailed geo-structural map of the northern smooth plains between<span class="Apple-converted-space">  </span>latitudes 29°N and 65°N. Our 1:100.000-scale map is obtained semi-automatically, using an algorithm to map all scarps from a DEM (3,4) followed by visual inspection and classification in ArcGIS. We created a DEM<span class="Apple-converted-space">  </span>using the raw MLA (Mercury Laser Altimeter) data (1) ,with 500 m/pix, and we used the Mercury Messenger MDIS (Mercury Dual Imaging System) (1,2) base map with 166m per pixel for the classification stage. With this approach, we mapped and characterized 51664 features on Mercury, creating a database with several morphometric attributes (e.g. length, azimuth, scarp height) which we will use to study the tectonic evolution of the smooth plains.<span class="Apple-converted-space"> </span></p> <p>In this way, we classified wrinkle ridges’s scarps, ghost craters, rim craters and central peaks. The morphometric parameters of the wrinkle ridges will<span class="Apple-converted-space">  </span>be quantitatively analyzed, in order to characterizer the possible tectonic process that could have formed them.</p> <p>This map can be considered an enhancement for the north pole of the global geological map of Mercury (1, 5).</p> <p> </p> <p>References</p> <ul> <li>Hawkins, S. E., III, et al. (2007), The Mercury Dual Imaging System on the MESSENGER spacecraft, Space Sci. Rev., 131, 247–338..<span class="Apple-converted-space"> </span></li> <li>Denevi, B. W., et al. (2013), The distribution and origin of smooth plains on Mercury, J. Geophys. Res. Planets, 118, 891–907, doi:10.1002/jgre.20075.</li> <li>Alegre Vaz, D. (2011). Analysis of a Thaumasia Planum rift through automatic mapping and strain characterization of normal faults. Planetary and Space Science, 59(11-12), 1210–1221. doi:10.1016/j.pss.2010.07.008 .</li> <li>Vaz, D. A., Spagnuolo, M. G., & Silvestro, S. (2014). Morphometric and geometric characterization of normal faults on Mars. Earth and Planetary Science Letters, 401, 83–94. doi:10.1016/j.epsl.2014.05.022.</li> <li>Kinczyk, M. J., Prockter, L., Byrne, P., Denevi, B., Buczkowski, D., Ostrach, L., & Miller, E. (2019, September). The First Global Geological Map of Mercury. In <em>EPSC-DPS Joint Meeting 2019</em> (Vol. 2019, pp. EPSC-DPS2019).</li> </ul>

scholarly journals Geological Characteristics of Unconventional Gas in Coal Measure of Upper Paleozoic Coal Measures in Ordos Basin, China

2016 ◽  
Vol 20 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Jinxian He ◽  
Xiaoli Zhang ◽  
Li Ma ◽  
Hongchen Wu ◽  
Muhammad Ashraf
Keyword(s):  
Shale Gas ◽  
Coalbed Methane ◽  
Oil And Gas ◽  
Ordos Basin ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
Unconventional Gas ◽  
Geological Characteristics ◽  
Upper Paleozoic ◽  
Coal Measures

<p>There are enormous resources of unconventional gas in coal measures in Ordos Basin. In order to study the geological characteristics of unconventional gas in coal Measures in Ordos Basin, we analyzed and summarized the results of previous studies. Analysis results are found that, the unconventional gas in coal measures is mainly developed in Upper Paleozoic in Eastern Ordos Basin, which including coalbed methane, shale gas and tight sandstone gas. The oil and gas show active in coal, shale and tight sandstone of Upper Paleozoic in Ordos Basin. Coalbed methane reservoir and shale gas reservoir in coal measures belong to “self-generation and self- preservation”, whereas the coal measures tight sandstone gas reservoir belongs to “allogenic and self-preservation”. The forming factors of the three different kinds of gasses reservoir are closely related and uniform. We have the concluded that it will be more scientific and reasonable that the geological reservoir-forming processes of three different kinds of unconventional gas of coal measures are studied as a whole in Ordos Basin, and at a later stage, the research on joint exploration and co-mining for the three types of gasses ought to be carried out.</p>

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