Seismic reservoir characterization in Marcellus shale

Interpretation, 2014

Evaluating and exploiting unconventional complex oil and gas reservoirs such as the Marcellus Shale gas reservoirs within the Appalachian Basin in Pennsylvania, USA, have gained considerable interest in recent years. Technologies such as conventional 3D seismic, horizontal drilling, and hydraulic fracturing have been at the forefront of the effort to exploit these resources. Recently, multicomponent seismic technologies have been integrated into some resource evaluation and reservoir characterization activities of low-permeability rock systems. We evaluated how multicomponent seismic technology provides value to reservoir characterization in shale gas exploration. We improved fault interpretations and natural fracture identifications by means of [Formula: see text] and [Formula: see text] integrated interpretation. In addition, using P-P-/P-SV-joint inversion, we extracted key parameters, such as [Formula: see text] ratio and density, that improve stratigraphic interpretation and ro...

Marine and Petroleum Geology, 2016

Defining the 3D geometry and internal architecture of reservoirs is important for prediction of hydrocarbon volumes, petroleum production and storage potential. Many reservoirs contain thin shale layers that are below seismic resolution, which act as impermeable and semi-permeable layers within a reservoir. Predicting the storage volume of a reservoir with thin shale layers from conventional seismic data is an issue due to limited seismic resolution. Further, gas chimneys indicative of gas migration pathways through thin shale layers, are not easily defined by conventional seismic data. Additional information, such as borehole data, can be used to aid mapping of shale layers, but making lateral predictions from 1D borehole data has high uncertainty. This paper presents an integrated workflow for quantitative seismic interpretation of thin shale layers and gas chimneys in the Utsira Formation of the Sleipner reservoir. The workflow combines the use of attribute and spectral analysis to add resolution to conventional seismic amplitude data. Detailed interpretation of these analyses reveals the reservoirs internal thin shale architecture, and the presence of gas chimneys. The comprehensive interpretation of the reservoirs internal structure is used to calculate a new reservoir storage volume. This is done based on the distribution of sand and interpreted shale layers within the study area, for this active CO2 storage site.

ASEG Extended Abstracts, 2018

Seismic integration has been a successful accessory in every data interpretation project. For shale gas exploration design, development and implementation, high-resolution seismic data are necessitated. In this context, every exploration project needs multi-disciplinary datasets and their integration that can minimize the ambiguity of the interpretative outcomes. What are the integrated solutions for imaging and interpreting shale gas and how do they impact our shale prospect business? How do we organize and standardize our integrated workflows to address issues of exploration, field development, including drilling campaigns of the unconventional reservoirs? So far, the conventional reservoirs of many worldwide basins did produce even without integrated workflows. With the increase in intricacy in structural and stratigraphic settings, in particular with the fractured shale environments, exploration and field development plans have become multifaceted, complicating the field operations. How do we take on the exploration, development and drilling campaign decisions using the integrated seismic solutions? How do we suggest the "integrated solutions" to our valued operators and service providers? Why are the conventional technologies failures and setbacks? How can we guide and recommend the petroleum companies on appropriate technologies and the reserve computations in shale environments? We come up with an "Integrated Seismic" (IS) strategy, addressing the issues and challenges. The applicability and feasibility of IS in various exploration projects including their execution and implementation in worldwide shale gas basins are discussed. IS has been playing a vital role, making huge impacts on the integrated interpretation projects, especially during prospect identification and risk evaluation stages.

ASEG Extended Abstracts, 2013

The Leading Edge, 2011

Surface seismic data have proven to be an invaluable asset for organizations producing hydrocarbons from unconventional resource plays. Initially, a primary benefit of surface seismic was the ability to locate and avoid drilling into zones with faults, fractures, and karsting which adversely affected the ability to complete the well successfully. More recent advances in prestack seismic data analysis yield attributes that appear to be correlated to formation lithology, rock strength, and stress fields. Knowledge and proper utilization of these attributes may prove valuable in the optimization of drilling and completion activities.

Interpretation

The Devonian Duvernay Formation in northwest central Alberta, Canada, has become a hot play in the past few years due to its richness in liquid and gaseous hydrocarbon resources. The oil and gas generation in this shale formation made it the source rock for many oil and gas fields in its vicinity. We attempt to showcase the characterization of Duvernay Formation using 3D multicomponent seismic data and integrating it with the available well log and other relevant data. This has been done by deriving rock-physics parameters (Young’s modulus and Poisson’s ratio) through deterministic simultaneous and joint impedance inversion, with appropriate quantitative interpretation. In particular, we determine the brittleness of the Duvernay interval, which helps us determine the sweet spots therein. The scope of this characterization exercise was extended to explore the induced seismicity observed in the area (i.e., earthquakes of magnitude [Formula: see text]) that is perceived to be associate...

2015

Summary This presentation will describe an unconventional case study in the context of an integrated interpretation workflow, incorporating converted-wave shear (PS) data. The objective of the case study was to enhance and improve the prediction of facies and geomechanical properties of a shale reservoir interval by incorporating the pre- and post-stack PS data. The conditioning, analysis and blending of the PS data into the more conventional workflow (which was presented at Geoconvention 2014) will be described to illustrate the successful integration of geological information and seismic attributes. The results of this expanded workflow will be compared to those achieved using the P-wave component only, with additional insight provided by a 3D VSP.

Pure and Applied Geophysics, 2017

Thin hydrocarbon reservoir facies pose resolution challenges and waveform-signature opportunities in seismic reservoir characterization and prospect identification. In this study, we present a case study, where instantaneous frequency variation in response to a thin hydrocarbon pay zone is analyzed and integrated with other independent information to explain drilling results and optimize future drilling decisions. In Morrison NE Field, some wells with poor economics have resulted from well-placement incognizant of reservoir heterogeneities. The study area in Clark County, Kanas, USA, has been covered by a surface 3D seismic reflection survey in 2010. The target horizon is the Viola limestone, which continues to produce from 7 of the 12 wells drilled within the survey area. Seismic attributes extraction and analyses were conducted with emphasis on instantaneous attributes and amplitude anomalies to better understand and predict reservoir heterogeneities and their control on hydrocarbon entrapment settings. We have identified a higher instantaneous frequency, lower amplitude seismic facies that is in good agreement with distinct lithofacies that exhibit better (higher porosity) reservoir properties, as inferred from well-log analysis and petrographic inspection of well cuttings. This study presents a pre-drilling, data-driven approach of identifying sub-resolution reservoir seismic facies in a carbonate formation. This workflow will assist in placing new development wells in other locations within the area. Our low amplitude high instantaneous frequency seismic reservoir facies have been corroborated by findings based on well logs, petrographic analysis data, and drilling results.

69th EAGE Conference and Exhibition incorporating SPE EUROPEC 2007, 2007

Proceedings of the 2nd Unconventional Resources Technology Conference, 2014

An integrated study of the well Zhao-104 and surrounding seismic volume within the shale gas reservoir in South China has been conducted with the objective of generating shale formation properties related to fracture orientation and intensity in the area and deriving such reservoir rock properties as data quality allows. Seismic attribute analysis of anisotropy from elliptical velocity inversion indicates that anisotropy varies horizontally and vertically, and that it is dominantly controlled by stress azimuth, which conforms to the current day stress field as independently determined from borehole break-outs. For the reservoir, it appears that the modern-day SH (N40E) orientation approximates the conjugate fracture orientation of a wrench-faulted tectonic regime; this map pattern suggests a clockwise net rotation of the stress field from time of deposition to the present-day by 40°. Very large strike-slip faults (cutting the survey) have low anisotropy. Intermediate strike-slip faults cutting the entire shale section may exhibit larger anisotropy. Structural depressions formed by transtension act as TOC-rich sinks and likewise feature large anisotropy vectors. Relative paleo-sea-level change influenced mineral assemblages and elastic properties of systems tracts. Of several interpreted transgressions, only the first transgressive phase is associated with significant TOC-deposition.

SEG Technical Program Expanded Abstracts 2013, 2013

Shale resources characterization has gained attention in the last decade or so, after the M ississippian Barnett shale was successfully developed with the application of hydraulic fracing and horizontal drilling. For characterization of shale gas formations different workflows using 3D surface seismic data have been introduced. We propose an integrated workflow for the characterization of the M ontney shale formation, one of the largest and economically viable resource plays in North America. We also compare results to those that were obtained by an existing workflow described elsewhere.

2019

A successful shale exploration strategy entails identification of “sweet spots” or the places with maximum potential for shale oil/gas and desirable brittle behavior (fracability). The total organic carbon (TOC) and Brittleness Index (BI) are the two important parameters that can assist in identification of such locales. Higher TOC or total organic carbon is generally associated with shale sequences having good hydrocarbon storage while the rocks with high BI values are more amenable to fracturing. The identified sweet spot should therefore exhibit high TOC and high BI values. Although identification of these intervals through core analysis in laboratorybased measurements can be very accurate but these are in-turn very expensive and time consuming!! The paper presents an integrated workflow for identification of sweet spots within shale plays using wire-line logs and seismic derived rock physical properties. A synthetic TOC log has been derived using Passey’s method with the lab der...

SEG Technical Program Expanded Abstracts 2011, 2011

Surface seismic data has proven to be an invaluable asset for organizations producing hydrocarbons from unconventional resource plays. Initially, one of the primary benefits of surface seismic was the ability to locate and avoid drilling into zones with faults, fractures and karsting which adversely affected the ability to complete the well successfully. More recent advances in pre-stack seismic data analysis yield attributes that appear to be correlated to formation lithology, rock strength and stress fields. Knowledge and proper utilization of these attributes may prove valuable in the optimization of drilling and completion activities. In this article we show an integrated seismic approach based on pre-stack azimuthal seismic data analysis and well log information to identify "sweet spots", estimate geomechanical properties and in-situ principal stresses.

SEG Technical Program Expanded Abstracts 2019

The Delaware and Midland Basins are multistacked plays with production being drawn from different zones. Of the various prospective zones in the Delaware Basin, the Bone Spring and Wolfcamp formations are the most productive and thus are the most-drilled zones. A 3D seismic survey was acquired in the northern part of Delaware Basin and after processing was picked up, to understand the reservoirs of interest and pick the sweet spots. We describe the whole reservoir characterization exercise that was carried out on this data in three different phases. We discuss phase 1 here, beginning with a brief description of the geology of the area and the stratigraphic column, and going on to the well ties for the different available wells over the 3D seismic survey, estimation of the shear curves where the measured shear curves were missing, the generation of an accurate low-frequency model for impedance inversion, preconditioning of the prestack seismic data, use of different lithotrends in inversion and finally the prestack simultaneous impedance inversion.

Proceedings of the 5th Unconventional Resources Technology Conference, 2017

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