3-D seismic imaging and seismic attribute analysis of genetic sequences deposited in low‐accommodation conditions

Geophysics ◽  
1996 ◽  
Vol 61 (5) ◽  
pp. 1351-1362 ◽  
Author(s):  
B. A. Hardage ◽  
D. L. Carr ◽  
D. E. Lancaster ◽  
J. L. Simmons ◽  
D. S. Hamilton ◽  
...  
Keyword(s):  
Seismic Data ◽  
Sediment Accumulation ◽  
Gas Reservoirs ◽  
Seismic Attribute ◽  
Gas Field ◽  
Reservoir System ◽  
Depositional Processes ◽  
Genetic Sequences ◽  
Data Windows ◽  
Reservoir Facies

A multidisciplinary team, composed of stratigraphers, petrophysicists, reservoir engineers, and geophysicists, studied a portion of Boonsville gas field in the Fort Worth Basin of North‐Central Texas to determine how modern geophysical, geological, and engineering techniques could be combined to understand the mechanisms by which fluvio‐deltaic depositional processes create reservoir compartmentalization in a low‐ to moderate‐accommodation basin. An extensive database involving well logs, cores, production, and pressure data from 200‐plus wells, [Formula: see text] [Formula: see text] of 3-D seismic data, vertical seismic profiles (VSPs), and checkshots was assembled to support this investigation. The reservoir system we studied was the Bend Conglomerate, a productive series of gas reservoirs composed of Middle Pennsylvanian fluvio‐deltaic clastics 900 to 1300 ft (275 to 400 m) thick in our project area. We were particularly interested in this reservoir system because evidence suggested that many of the sequences in this stratigraphic interval were deposited in low‐accommodation conditions (that is, in an environment where there was limited vertical space available for sediment accumulation), and our objective was to investigate how fluvio‐deltaic reservoirs were compartmentalized by low‐accommodation depositional processes. Using an extensive well log database (200 plus wells) and a core‐calibrated calculation of rock facies derived from these logs, we divided the Bend Conglomerate interval into ten genetic sequences, with each sequence being approximately 100 ft (30 m) thick. We then used local VSP and checkshot control to transform log‐measured depths of each sequence boundary to seismic two‐way time coordinates and identified narrow seismic data windows encompassing each sequence across the [Formula: see text] [Formula: see text] 3-D seismic grid. A series of seismic attributes was calculated in these carefully defined data windows to determine which attributes were reliable indicators of the presence of productive reservoir facies and which attributes could, therefore, reveal distinct reservoir compartments and potentially show where infield wells should be drilled to reach previously uncontacted gas reservoirs. Our best success was the seismic attribute correlations we found in the Upper and Lower Caddo sequences, at the top of the Bend Conglomerate. These sequences were deposited in a low‐accommodation setting, relative to other Boonsville sequences, and we found that reflection amplitude and instantaneous frequency, respectively, were reliable indicators of the areal distribution of reservoir facies in these low‐accommodation sequences.

On: “3-D seismic imaging and seismic attribute analysis of genetic sequences deposited in low‐ accommodation conditions” (B. A. Hardage, D. L. Carr, D.E. Lancaster, J. L. Simmons Jr., D. S. Hamilton, R. Y. Elphick, K. L. Oliver, and R. A. Johns, GEOPHYSICS, 61, 1351–1362)

Geophysics ◽  
1997 ◽  
Vol 62 (6) ◽  
pp. 1996-1998
Author(s):  
Miodrag M. Roksandić
Keyword(s):  
Fort Worth ◽  
Seismic Attribute ◽  
Gas Field ◽  
Fort Worth Basin ◽  
Multidisciplinary Study ◽  
Depositional Processes ◽  
Attribute Analysis ◽  
Reservoir Compartmentalization ◽  
Central Texas ◽  
Genetic Sequences

The paper deals with the results of a multidisciplinary study of the Bend Conglomerate (Middle Pennsylvanian fluvio‐deltaic clastics) in a portion of Boonsville gas field in the Fort Worth Basin of North‐Central Texas, especially with those related to the Caddo sequence, at the top of the Bend Conglomerate. The purpose of the study was “to determine how modern geophysical, geological, and engineering techniques could be combined to understand the mechanisms by which fluvio‐deltaic depositional processes create reservoir compartmentalization in a low‐ to moderate‐accommodation basin.” According to Hardage et al. (1996), complexly arranged key chronostratigraphic surfaces are major controls on compartmentalization and architecture of reservoirs. These key chronostratigraphic surfaces are flooding surfaces, maximum flooding surfaces, and erosion surfaces.

scholarly journals Prediction of Shale Gas Reservoirs Using Fluid Mobility Attribute Driven by Post-Stack Seismic Data: A Case Study from Southern China

2020 ◽  
Vol 11 (1) ◽  
pp. 219
Author(s):  
Jing Zeng ◽  
Alexey Stovas ◽  
Handong Huang ◽  
Lixia Ren ◽  
Tianlei Tang
Keyword(s):  
Shale Gas ◽  
Seismic Data ◽  
Spectral Decomposition ◽  
Southern China ◽  
Gas Reservoirs ◽  
Seismic Attribute ◽  
Longmaxi Formation ◽  
Shale Gas Reservoirs ◽  
The Sichuan Basin ◽  
Shale Reservoirs

Paleozoic marine shale gas resources in Southern China present broad prospects for exploration and development. However, previous research has mostly focused on the shale in the Sichuan Basin. The research target of this study is expanded to the Lower Silurian Longmaxi shale outside the Sichuan Basin. A prediction scheme of shale gas reservoirs through the frequency-dependent seismic attribute technology is developed to reduce drilling risks of shale gas related to complex geological structure and low exploration level. Extracting frequency-dependent seismic attribute is inseparable from spectral decomposition technology, whereby the matching pursuit algorithm is commonly used. However, frequency interference in MP results in an erroneous time-frequency (TF) spectrum and affects the accuracy of seismic attribute. Firstly, a novel spectral decomposition technology is proposed to minimize the effect of frequency interference by integrating the MP and the ensemble empirical mode decomposition (EEMD). Synthetic and real data tests indicate that the proposed spectral decomposition technology provides a TF spectrum with higher accuracy and resolution than traditional MP. Then, a seismic fluid mobility attribute, extracted from the post-stack seismic data through the proposed spectral decomposition technology, is applied to characterize the shale reservoirs. The application result indicates that the seismic fluid mobility attribute can describe the spatial distribution of shale gas reservoirs well without well control. Based on the seismic fluid mobility attribute section, we have learned that the shale gas enrich areas are located near the bottom of the Longmaxi Formation. The inverted velocity data are also introduced to further verify the reliability of seismic fluid mobility. Finally, the thickness map of gas-bearing shale reservoirs in the Longmaxi Formation is obtained by combining the seismic fluid mobility attribute with the inverted velocity data, and two favorable exploration areas are suggested by analyzing the thickness, structure, and burial depth. The present work can not only be used to evaluate shale gas resources in the early stage of exploration, but also help to design the landing point and trajectory of directional drilling in the development stage.

Characterizing tight sand gas reservoirs using 3D3C seismic data in Sulige gas field

2012 ◽  
Author(s):  
Daxing Wang ◽  
Yuhua Zhao ◽  
Mengbo Zhang ◽  
Yonggang Wang ◽  
Xinwei He ◽  
...  
Keyword(s):  
Seismic Data ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Tight Sand Gas

3-D seismic stratal‐surface concepts applied to the interpretation of a fluvial channel system deposited in a high‐accomodation environment

Geophysics ◽  
1999 ◽  
Vol 64 (2) ◽  
pp. 609-620 ◽  
Author(s):  
Bob A. Hardage ◽  
Randy L. Remington
Keyword(s):  
Seismic Data ◽  
Seismic Stratigraphy ◽  
Reference Surface ◽  
Fluvial System ◽  
Seismic Attribute ◽  
Depositional Sequence ◽  
Channel System ◽  
Geologic Time ◽  
Depositional Processes ◽  
Reflection Peak

A fundamental thesis of seismic stratigraphy is that seismic reflections follow impedance contrasts that coincide with stratal surfaces, which are surfaces where depositional processes occur at a fixed moment in geologic time. This stratal‐surface concept is used in this paper to image a narrow (width ∼300 ft or 90 m), thin, fluvial channel system that is embedded within a seismic reflection peak that reflects from a large (about 2 × 2 mi or 3.2 × 3.2 km) area of nonchannel facies that dominate the waveshape of the reflection peak. The targeted channel facies are confined to an interval that vertically spans less than 30 ft. According to principles of seismic stratigraphy, four conformable seismic stratal surfaces that pass through the interior of this channel sequence were constructed across a 2 × 2-mi (3.2 × 3.2-km) (approximately) area of a 3-D seismic‐data volume. The channel images portrayed on these seismic horizons, which were spaced at vertical increments of 2 ms, illustrate the principle that seismic attributes viewed on seismic stratal surfaces provide valuable images of facies distributions within thin‐bed sequences and help seismic interpreters segregate channel facies from nonchannel facies. These stratal‐surface interpretations of the fluvial system were then integrated to create a thin (8-ms-thick), stratal‐bounded seismic‐data window that spans the short geologic time period during which the targeted fluvial depositional system was active. Seismic‐attribute calculations within this stratal‐bounded analysis window improve parts of the channel image by integrating the facies information from all stratal surfaces into a unified seismic attribute that vertically spans the total depositional sequence. A comparison is made between channel images on seismic stratal surfaces that are conformable to two different reference surfaces, one reference surface being positioned below the targeted fluvial system and the second reference surface being above the thin‐bed channels. This comparison supports the premise that seismic interpreters should extrapolate stratal surfaces both upward and downward across a thin‐bed target to optimize the image of that target.

Hydrocarbon indicators on seismic data: Insights from poroviscoelastic modeling, amplitude, and frequency variation with offsets from the Drake Point gas field, Western Arctic Islands, Canada

2014 ◽  
Vol 2 (4) ◽  
pp. SP45-SP59
Author(s):  
Mathieu J. Duchesne ◽  
Bernard Giroux ◽  
Kezhen Hu
Keyword(s):  
Seismic Data ◽  
Low Frequency ◽  
Frequency Variation ◽  
Class Iii ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Amplitude Variation With Offset ◽  
Seismic Amplitude ◽  
Impedance Modeling ◽  
Western Arctic

The evaluation of drilling prospects is frequently based on seismic amplitude anomalies. To decipher “true” seismic prospects from “false” ones, we used poroviscoelastic (PVE) models, as opposed to other formalisms such as acoustic, elastic, viscoelastic, and poroelastic models, that provided a solution that takes into account solid and fluid attenuation mechanisms separately to model the earth’s response to the propagation of a seismic wavefield. Here, a PVE impedance modeling scheme was tested using seismic and well-log data collected on a conventional gas reservoir in the Canadian Arctic. Comparisons between seismic-to-well ties achieved using acoustic and PVE media indicated that the latter provided more realistic synthetic seismograms. Although prestack analysis revealed that the present lithological context was of class I amplitude variation with offset (AVO), the seismic signature observed was of class III AVO. Consequently, the increase in amplitude with offset was interpreted to be induced not by a lithological change (i.e., shale to sand) combined with a gas-charged interval, but rather by an increase in porosity within the sandstone reservoir itself where the gas has accumulated. Frequency variation with offset analysis using spectral decomposition, image low-frequency shadows on the far offsets attributed to the gas accumulation that were correlative with the AVO anomaly. This highlighted the importance of far offsets in anomalous amplitude and frequency events attributed to the occurrence of gas reservoirs observed on stacked data and that these events can be missed if seismic hydrocarbon indicators were solely investigated on stacked data. Finally, the method of analysis emphasized the importance of combining indirect arguments coming from the observation of prestack and stacked seismic data in the time and frequency domains for reducing risk to an acceptable level before a prospect can be drilled.

Detailed Lithological Study Leads to New Insights about the Pre-Tertiary and Tertiary Reservoirs in the Suban Gas Field, South Sumatra Basin, Indonesia

2021 ◽  
Author(s):  
B. R. Permana
Keyword(s):  
Seismic Data ◽  
Common Knowledge ◽  
Crystalline Rock ◽  
Carbonate Reservoir ◽  
Age Dating ◽  
Integrated Analysis ◽  
The South ◽  
Gas Field ◽  
Absolute Age ◽  
Reservoir Facies

The basement igneous intrusive rock lithology in the South Sumatra Basin was previously suggested to be a solely granitic rock. It is also a common knowledge that the Miocene Baturaja Formation carbonates are one of the prolific reservoirs. However, after a comprehensive reservoir recharacterization had been conducted in the Suban Field, new insights regarding these two rock types were revealed. The basement lithology consists of a more complex metasediment containing Andesite, Granodiorite, and Gabbro and an Oligocene-age carbonate reservoir was also identified. The reservoir recharacterization was carried out by conducting an integrated analysis to reconstruct the complex reservoir configuration utilizing seismic data, core, cuttings, absolute age dating, and biostratigraphy. Seismic data was utilized as a general framework for reservoir architecture due to the resolution that allowed to describe the reservoir configuration in detail. Core and cuttings were used to identify the reservoir facies, and absolute age dating along with biostratigraphy were used to construct geochronology for each reservoir facies. Finally, well to well correlation was performed to reconstruct complex reservoir configurations. The result of the study indicated that the reservoir age in the field can be divided into two parts, pre-Tertiary (PRT) basement and Tertiary sediments. The PRT of Suban Field comprises several types of crystalline rock that will have different respond to the stresses and the Tertiary section that consists of clastic and several carbonate facies of different ages that vary across the study area. This study offers new insights regarding the basement configuration and the emerging carbonate play. Different igneous rock compositions reflect a complex magmatism process in South Sumatra. Oligocene carbonates that were identified in Suban could open the opportunity to discover a hydrocarbon-bearing Oligocene carbonate play in the South Sumatra Basin.

scholarly journals Pitfalls and limitations in seismic attribute interpretation of tectonic features

2015 ◽  
Vol 3 (1) ◽  
pp. SB5-SB15 ◽  
Author(s):  
Kurt J. Marfurt ◽  
Tiago M. Alves
Keyword(s):  
Seismic Data ◽  
Seismic Attributes ◽  
Seismic Attribute ◽  
3D Data ◽  
Amplitude Data ◽  
Seismic Sections ◽  
Push Down ◽  
Data Coherence ◽  
Level Of Experience ◽  
Tectonic Features

Seismic attributes are routinely used to accelerate and quantify the interpretation of tectonic features in 3D seismic data. Coherence (or variance) cubes delineate the edges of megablocks and faulted strata, curvature delineates folds and flexures, while spectral components delineate lateral changes in thickness and lithology. Seismic attributes are at their best in extracting subtle and easy to overlook features on high-quality seismic data. However, seismic attributes can also exacerbate otherwise subtle effects such as acquisition footprint and velocity pull-up/push-down, as well as small processing and velocity errors in seismic imaging. As a result, the chance that an interpreter will suffer a pitfall is inversely proportional to his or her experience. Interpreters with a history of making conventional maps from vertical seismic sections will have previously encountered problems associated with acquisition, processing, and imaging. Because they know that attributes are a direct measure of the seismic amplitude data, they are not surprised that such attributes “accurately” represent these familiar errors. Less experienced interpreters may encounter these errors for the first time. Regardless of their level of experience, all interpreters are faced with increasingly larger seismic data volumes in which seismic attributes become valuable tools that aid in mapping and communicating geologic features of interest to their colleagues. In terms of attributes, structural pitfalls fall into two general categories: false structures due to seismic noise and processing errors including velocity pull-up/push-down due to lateral variations in the overburden and errors made in attribute computation by not accounting for structural dip. We evaluate these errors using 3D data volumes and find areas where present-day attributes do not provide the images we want.

Predict Channel Sand Body Distribution Characteristics of South Eighth District Based on RMS Amplitude Attributes & Frequency Division

2013 ◽  
Vol 734-737 ◽  
pp. 404-407 ◽  
Author(s):  
Yu Shuang Hu ◽  
Si Miao Zhu
Keyword(s):  
Seismic Data ◽  
Physical Property ◽  
Sedimentary Facies ◽  
Distribution Area ◽  
Frequency Division ◽  
Root Mean Square Amplitude ◽  
Seismic Attribute ◽  
Body Distribution ◽  
Attribute Analysis ◽  
Sand Body

A big tendency in oil industry is underestimating the heterogeneity of the reservoir and overestimating the connectivity, which results in overly optimistic estimates of the capacity. With the development of seismic attributes, we could pick up hidden reservoir lithology and physical property information from the actual seismic data, strengthen seismic data application in actual work, to ensure the objectivity of the results. In this paper, the channel sand body distribution in south eighth district of oilfield Saertu is predicted through seismic data root-mean-square amplitude and frequency division to identify sand body boundaries, predict the distribution area channel sand body characteristics successfully, which consistent with the sedimentary facies distribution. The result proves that seismic attribute analysis has good practicability in channel sand body prediction and sedimentary facies description.

A Study of Downhole Drillable Pulsing Cementing Device with Low Frequency Self-Excited Hydraulic Oscillation and its Field Application

2012 ◽  
Vol 450-451 ◽  
pp. 1536-1539
Author(s):  
Cui Ping Nie ◽  
Deng Sheng Ye
Keyword(s):  
Setting Time ◽  
Low Frequency ◽  
Field Application ◽  
Displacement Efficiency ◽  
Cement Slurry ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Gas Well ◽  
Hydraulic Oscillation ◽  
Injection Technology

Abstract: Usually we pay more attention on how to improve gas well cementing quality in engineering design and field operations, and there are so many studies on cement agents but few researches on cement slurry injection technology. The field practice proved that conventional cementing technology can not ensure the cementing quality especially in gas well and some abnormal pressure wells. Most of the study is concentrated on cement agents and some cementing aspects such as wellbore condition, casing centralization etc. All the factors analysis on cementing quality has pointed out that a combination of good agents and suitable measurements can improve cementing quality effectively. The essential factor in cementing is to enhance the displacement efficiency, but normal hole condition and casing centralization are the fundamental for cementing only. Pulsing cementing is the technology that it can improve the displacement efficiency especially in reservoir well interval, also it can shorten the period from initial to ultimate setting time for cement slurry or improve thickening characteristics, and then to inhibit the potential gas or water channeling. Based on systematically research, aiming at improving in 7″ liner cementing, where there are multi gas reservoirs in long interval in SiChuan special gas field, well was completed with upper 7″ liner and down lower 5″ liner, poor cementing bonding before this time. So we stressed on the study of a downhole low frequency self-excited hydraulic oscillation pulsing cementing drillable device and its application, its successful field utilization proved that it is an innovative tool, and it can improve cementing quality obviously.

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