Preconditioning point-source/point-receiver high-density 3D seismic data for lacustrine shale characterization in a loess mountain area

2017 ◽  
Vol 5 (2) ◽  
pp. SF177-SF188 ◽  
Author(s):  
Wei Wang ◽  
Xiangzeng Wang ◽  
Hongliu Zeng ◽  
Quansheng Liang
Keyword(s):  
Data Quality ◽  
Seismic Data ◽  
Ordos Basin ◽  
Seismic Inversion ◽  
High Density ◽  
Seismic Survey ◽  
3D Seismic ◽  
Noise Characteristics ◽  
Lacustrine Shale ◽  
3D Seismic Data

In the study area, southeast of Ordos Basin in China, thick lacustrine shale/mudstone strata have been developed in the Triassic Yanchang Formation. Aiming to study these source/reservoir rocks, a 3D full-azimuth, high-density seismic survey was acquired. However, the surface in this region is covered by a thick loess layer, leading to seismic challenges such as complicated interferences and serious absorption of high frequencies. Despite a specially targeted seismic processing workflow, the prestack Kirchhoff time-migrated seismic data were still contaminated by severe noise, hindering seismic inversion and geologic interpretation. By taking account of the particular data quality and noise characteristics, we have developed a cascade workflow including three major methods to condition the poststack 3D seismic data. First, we removed the sticky coherent noise by a local pseudo [Formula: see text]-[Formula: see text]-[Formula: see text] Cadzow filtering. Then, we diminished the random noise by a structure-oriented filtering. Finally, we extended the frequency bandwidth with a spectral-balancing method based on the continuous wavelet transform. The data quality was improved after each of these steps through the proposed workflow. Compared with the original data, the conditioned final data show improved interpretability of the shale targets through geometric attribute analysis and depositional interpretation.

Application of 3D seismic attributes to optimize the placement of horizontal wells within a tight gas sand reservoir, Ordos Basin, China

Geophysics ◽  
2016 ◽  
Vol 81 (3) ◽  
pp. B77-B86 ◽  
Author(s):  
Zhiguo Wang ◽  
Jinghuai Gao ◽  
Xiaolan Lei ◽  
Xiaojie Cui ◽  
Daxing Wang
Keyword(s):  
Seismic Data ◽  
Ordos Basin ◽  
Horizontal Wells ◽  
Tight Gas ◽  
3D Seismic ◽  
Seismic Attribute ◽  
Horizontal Drilling ◽  
The Ordos Basin ◽  
Gas Bearing ◽  
3D Seismic Data

The Lower Permian Xiashihezi Formation in the Ordos Basin, China, is a quartz-sandstone reservoir with low porosity and low permeability. We have acquired 3D seismic data and well data from 18 vertical and four horizontal wells to indicate the potential of seismic attribute analyses in locating seismic sweet spots for lateral placement of horizontal wells. Using the analytic wavelet transform with a Morse wavelet, the integration of high tuning spectral components, high sweetness and high spectral attenuation helped us to estimate the distribution of gas-bearing tight sands in the Xiashihezi Formation. Our results revealed that the principal target of horizontal drilling and production was gas-bearing massive point bars in the braided river delta setting of the Ordos Basin. The integrated workflow of the seismic attribute analysis contributes to the optimal horizontal well planning by mining and exposing critical geological information of a tight gas sand reservoir from within 3D seismic data.

Why 3D seismic data are an asset for exploration and mine planning? Velocity tomography of weakness zones in the Kevitsa Ni-Cu-PGE mine, northern Finland

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. B33-B46 ◽  
Author(s):  
Alireza Malehmir ◽  
Ari Tryggvason ◽  
Chris Wijns ◽  
Emilia Koivisto ◽  
Teemu Lindqvist ◽  
...  
Keyword(s):  
Seismic Data ◽  
Mine Planning ◽  
Seismic Survey ◽  
Open Pit ◽  
3D Seismic ◽  
Reflection Data ◽  
Northern Side ◽  
Weakness Zone ◽  
Weakness Zones ◽  
3D Seismic Data

Kevitsa is a disseminated Ni-Cu-PGE (platinum group elements) ore body in northern Finland, hosted by an extremely high-velocity ([Formula: see text]) ultramafic intrusion. It is currently being mined at a depth of approximately 100 m with open-pit mining. The estimated mine life is 20 years, with the final pit reaching a depth of 500–600 m. Based on a series of 2D seismic surveys and given the expected mine life, a high-resolution 3D seismic survey was justified and conducted in the winter of 2010. We evaluate earlier 3D reflection data processing results and complement that by the results of 3D first-arrival traveltime tomography. The combined results provide insights on the nature of some of the reflectors within the intrusion. In particular, a major discontinuity, a weakness zone, is delineated in the tomography results on the northern side of the planned pit. Supported by the reflection data, we estimate the discontinuity, likely a thrust sheet, to extend down approximately 600 m and laterally 1000 m. The weakness zone terminates prominent internal reflectivity of the Kevitsa intrusion, and it is associated with the extent of the economic mineralization. Together with other weakness zones, a couple of which are also revealed by the tomography study, the discontinuity forms a major wedge block that influences the mine bench stability on the northern side of the open pit and likely will cause more issues during the extraction of the ore in this part of the mine. We argue that 3D seismic data should routinely be acquired prior to commencement of mining activities to maximize exploration efficiency at depth and also to optimize mining as it continues toward depth. Three-dimensional seismic data over mineral exploration areas are valuable and can be revisited for different purposes but are difficult to impossible to acquire after mining has commenced.

Reservoir characterization using microseismic facies analysis integrated with surface seismic attributes

2016 ◽  
Vol 4 (2) ◽  
pp. T167-T181 ◽  
Author(s):  
Aamir Rafiq ◽  
David W. Eaton ◽  
Adrienne McDougall ◽  
Per Kent Pedersen
Keyword(s):  
Seismic Data ◽  
Principal Curvature ◽  
Facies Analysis ◽  
Shape Index ◽  
Seismic Attributes ◽  
Seismic Survey ◽  
3D Seismic ◽  
Frequency Distributions ◽  
Scaling Properties ◽  
3D Seismic Data

We have developed the concept of microseismic facies analysis, a method that facilitates partitioning of an unconventional reservoir into distinct facies units on the basis of their microseismic response along with integrated interpretation of microseismic observations with 3D seismic data. It is based upon proposed links between magnitude-frequency distributions and scaling properties of reservoirs, including the effects of mechanical bed thickness and stress heterogeneity. We evaluated the method using data from hydraulic fracture monitoring of a Late Cretaceous tight sand reservoir in central Alberta, in which microseismic facies can be correlated with surface seismic attributes (primarily principal curvature, coherence, and shape index) from a coincident 3D seismic survey. Facies zones are evident on the basis of attribute crossplots, such as maximum moment release rate versus cluster azimuth. The microseismically defined facies correlate well with principal curvature anomalies from 3D seismic data. By combining microseismic facies analysis with regional trends derived from log and core data, we delineate reservoir partitions that appear to reflect structural and depositional trends.

scholarly journals Geohazard detection using 3D seismic data to enhance offshore scientific drilling site selection

2020 ◽  
Vol 28 ◽  
pp. 1-27 ◽  
Author(s):  
David R. Cox ◽  
Paul C. Knutz ◽  
D. Calvin Campbell ◽  
John R. Hopper ◽  
Andrew M. W. Newton ◽  
...  
Keyword(s):  
Site Selection ◽  
Seismic Data ◽  
Seismic Survey ◽  
3D Seismic ◽  
Seismic Reflection Data ◽  
Scientific Drilling ◽  
The North ◽  
Reflection Data ◽  
3D Seismic Data ◽  
Geohazard Assessment

Abstract. A geohazard assessment workflow is presented that maximizes the use of 3D seismic reflection data to improve the safety and success of offshore scientific drilling. This workflow has been implemented for International Ocean Discovery Program (IODP) Proposal 909 that aims to core seven sites with targets between 300 and 1000 m below seabed across the north-western Greenland continental shelf. This glaciated margin is a frontier petroleum province containing potential drilling hazards that must be avoided during drilling. Modern seismic interpretation techniques are used to identify, map and spatially analyse seismic features that may represent subsurface drilling hazards, such as seabed structures, faults, fluids and challenging lithologies. These hazards are compared against the spatial distribution of stratigraphic targets to guide site selection and minimize risk. The 3D seismic geohazard assessment specifically advanced the proposal by providing a more detailed and spatially extensive understanding of hazard distribution that was used to confidently select eight new site locations, abandon four others and fine-tune sites originally selected using 2D seismic data. Had several of the more challenging areas targeted by this proposal only been covered by 2D seismic data, it is likely that they would have been abandoned, restricting access to stratigraphic targets. The results informed the targeted location of an ultra-high-resolution 2D seismic survey by minimizing acquisition in unnecessary areas, saving valuable resources. With future IODP missions targeting similarly challenging frontier environments where 3D seismic data are available, this workflow provides a template for geohazard assessments that will enhance the success of future scientific drilling.

Technology, investment and people: a process for extending the life of the Central Fields Complex, Gippsland Basin

2008 ◽  
Vol 48 (1) ◽  
pp. 133
Author(s):  
Michael Gross ◽  
Abdul Aziz Abdul Rahim ◽  
Erin Broad ◽  
Dean Grant ◽  
Brad Hargreaves
Keyword(s):  
Data Integration ◽  
Data Quality ◽  
Seismic Data ◽  
Depositional Environments ◽  
3D Seismic ◽  
Initial Development ◽  
Technology Investment ◽  
Technical Advances ◽  
Gippsland Basin ◽  
3D Seismic Data

The greater Central Fields complex of the Gippsland Basin, comprised of the Halibut, Fortescue and Mackerel fields, has produced 1.7 billion barrels of oil from four platforms in 37 years of production. After the initial development drilling phases from Halibut (1969–70), Mackerel (1977–80), Fortescue (1983–86) and Cobia (1983–85) platforms and five in-fill drilling campaigns (1992–2003) it is still possible to target unswept highly productive multi-darcy reservoirs along with bypassed zones in lower quality sands. During 2007, a six well program was completed from the Halibut platform using an upgraded workover rig that added significant volumes with combined initial rates of more than 16,000 barrels of oil per day. In addition, despite being conductor limited, the program tested strategic concepts and demonstrated significant remaining potential in a variety of reservoir qualities and depositional environments. The outstanding success of the 2007 program was based on an up-to-date geologic framework, key technical advances, ongoing investment commitment and multi-discipline integration across workplace functions. Advancements in 3D seismic data quality and analyses, reservoir surveillance, innovative slot recovery and data integration all played a role in the success of the program. Building on the success elements of the 2007 program, a higher capacity rig has been mobilised and upgraded to apply new drilling technologies to access the remaining potential and help mitigate basin decline.

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