Top PDF Seismic Attributes for Carbonates

Seismic Attributes for Carbonates

Seismic Attributes for Carbonates

Even though a class 4 response frequently is associated with gas saturation (e.g., Castagna and Swan, 1997), this study has shown that this response can also be achieved as a result of other rock properties. However, when results were plotted in an intercept-gradient plot, this revealed a trend-line which fits all data points for variations of the considered factors quite accurately, except for values for fluid substitution, and values for pore model 1, and for very low porosity (Figure 6.29 b)). When more gas was present in the saturating fluid, intercept and gradient values deviated more from the trend-line, caused by reduced gradients and intercepts compared to full brine saturation. Thus, even though the interface studied felled into a class 4 both when fully brine saturated with original intrinsic rock properties, and when saturated with other fluid compositions, and for variations of other parameters, saturation by fluid compositions containing amounts of gas and/or oil could be separated from brine saturation, and from other factors. Thus, AVO studies may be valuable for fluid detection in carbonates, even though their complexity is high, which may give rise to considerable velocity variations. This is supported by observations of other authors. Li et al. (2003) have stated that fluids do affect carbonate rock properties with significant magnitude, and have found class 3 and 4 AVO effects to correspond to good quality reservoirs. Eissa et al. (2003) have observed a smaller intercept for gas-saturated dolomite than for tight limestone, and a small positive gradient for gas-dolomite, while tight limestone exhibits a larger negative gradient. Gas saturation of facies 2 gave a low intercept and a small positive gradient.
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Seismic Interpretation of Basement Faults Using Seismic Attributes – Using a Case Study of the Anding Field

Seismic Interpretation of Basement Faults Using Seismic Attributes – Using a Case Study of the Anding Field

Fractured basements are now considered to be new hydrocarbon plays, and recently, reservoirs in the Vietnam offshore area have been producing from the basement rock. Basement plays in the Malay Basin such as the Anding field is also now being extensively studied and explored for the possibility of their fractured basements to act as reservoirs. Since the basement in the Malay Basin varies from metasediments, to volcanics, granites, and then carbonates, the basement rock lacks primary porosity (Bishop, 2002). Swamps of fractures found in the basement were induced due to regional extensional or compressional forces during tectonic episodes, and these fractures act as the contributor for secondary porosity of the basement rocks for they provide interconnectivity and permeability. Fault zones are associated to be the weak zones and these zones can be further associated to neighbouring fracture zones. Having delineated faults that cut through the basement; this will help indicate where the possible zones of fracture nearby are. Besides that, faults also do act as a conduit of flow as well as a structural trap in hydrocarbon reservoirs. Faults are also generally regarded as shear fractures or extension fractures at the scale of an outcrop or greater ("Brittle deformation,")
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RESERVOIR STUDIES USING SEISMIC ATTRIBUTES AND WELL LOG AND WELL LOG ANALYSIS OF Y FIELD, NIGER DELTA

RESERVOIR STUDIES USING SEISMIC ATTRIBUTES AND WELL LOG AND WELL LOG ANALYSIS OF Y FIELD, NIGER DELTA

Gamma ray logs Shale usually contains small quantity of radioactive elements such as uranium (U) potassium (k) and thorium (TH). This produces gamma ray radiation from which the source can be detected by spectrometry. The log thus, detects shale horizon and can provide an estimate of the clay content and other sedimentary rocks. Amongst, the sediments, shales have by far the strongest radiation. That is why the log is called “Shale Log”. Gamma ray logs are usually expressed in API units. API is defined as 1/200 of the response generated by calibration standard, which is an artificial formation containing precisely known qualities of the three (3) radioactive elements, maintained by the American Petroleum Institute (API), Houston Texas.Shale–free sandstones and carbonates have low concentrations of radioactive materials and give low gamma ray readings. GR logs are usually recorded in track 1 with its scales chosen locally, but 0-100 or 0-150 API is common. It can be measured in both open and cased holes.
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The role of amorphous precursors in the crystallization of La and Nd carbonates.

The role of amorphous precursors in the crystallization of La and Nd carbonates.

sen et al. (2010) 58 and Beck and Andreassen (2010) 62 thus, it is not surprising that we observed spherulitic growth. The high SI values suggest that the supersaturation condition for spherulitic growth would have been fulfilled if the crystals were formed directly from solution. Nevertheless in our experi- ments La- and Nd-bearing crystalline carbonates formed via amorphous precursors, meaning that the aqueous solution had to be in equilibrium with ALC or ANC prior to the for- mation of the crystalline phases. There is however, no data about the solubility products of these precursors available and therefore calculating SI values for crystalline La and Nd car- bonates when the aqueous solution was in equilibrium with ALC or ANC is impossible. Yet, it is well known that amor- phous precursors are usually more soluble than the crystalline phases they transform into. The best-known example is ACC, which is one order of magnitude more soluble than vaterite or calcite. 48
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The role of amorphous precursors in the crystallization of La and Nd carbonates

The role of amorphous precursors in the crystallization of La and Nd carbonates

major REE carbonates occurring in natural REE deposits also contain F − as well as OH − in their structures (see references in Table SI-1†). Many studies have addressed the crystalline pro- ducts of the synthesis of REE carbonates from aqueous solu- tions as a function of crystallization temperature, pressure, nature and concentrations of reagents or stirring. 32–34 Further- more, some studies have focused on the e ff ect of the ionic radii of di ff erent REEs on the crystal structure of the crystalline product. 33,35 However, information about the early stages of the precipitation reactions and the role that amorphous pre- cursors or metastable intermediates may play in the crystalliza- tion pathways is surprisingly scarce. Recently, we have shown 36 that dysprosium (Dy) carbonates form via the crystallization of a highly hydrated amorphous precursor (amorphous dyspro- sium carbonate, Dy 2 (CO 3 ) 3 ·4H 2 O). A few studies mention the
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Transport-controlled hydrothermal replacement of calcite by Mg-carbonates

Transport-controlled hydrothermal replacement of calcite by Mg-carbonates

Reactive transport models are 33 used to predict the rates and spatial patterns of dolomitization e.g., Wilson et al., 2001; 34 Jones and Xiao, 2005; Whitaker and Xiao, 2010 and apply da[r]

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Carbonates from Olduvai Gorge, Tanzania: Palaeohydrology and geochronology

Carbonates from Olduvai Gorge, Tanzania: Palaeohydrology and geochronology

Palaeolake Olduvai formed in a shallow, rift shoulder basin on the edge of what is now the Serengeti Plain, supplied by fluvial delivery draining from the alluvial fan to the east and from the craton in the west (Hay, 1976). Similar to many lakes in the region today palaeolake Olduvai has been interpreted to have been saline with a high pH of ~9.5-10 (Hay and Kyser, 2001). The lake appears to have been persistent and from stratigraphic considerations likely no more than a few metres deep, perhaps up to 10 metres at highstands (Hay, 1976). The lacustrine sediments are primarily olive-green, waxy, Mg-rich smectite and interlayered illite/smectite clays derived largely by alteration of volcaniclastic material by reaction with the saline, alkaline lake water, and partially from unaltered detrital material (Deocampo et al., 2002; Hay and Kyser, 2001; Mees et al., 2007). In addition, the lake basin trapped episodic influxes of the volcaniclastic deposits are used to correlate the stratigraphy across the gorge. This depositional complex produced a unique stratigraphy of interbedded lake sediments, sandstones and tuffs, and provided host sediments for the authigenic precipitation of carbonates (Figure 5-3).
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Lithostratigraphy, sedimentology and diagenesis of the Ordovician carbonates, southern Thailand

Lithostratigraphy, sedimentology and diagenesis of the Ordovician carbonates, southern Thailand

Veizer, 1986, Ordovician spars in the Gordon Limestone, Tasmania Wang and Rao, 1989, and Ordovician cements from Nevada Ross et al., 1975, the 18Q values of marine cements in the Thung S[r]

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Quantification of wettability characteristics for carbonates using different salinities

Quantification of wettability characteristics for carbonates using different salinities

Further decrease in the salinity shows an insignificant effect on the contact angle behavior Different effects on the contact angle were obtained for three o kinds of dead crude oil exam[r]

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Novel geochemical fingerprints of biogenicity applied to ancient carbonates

Novel geochemical fingerprints of biogenicity applied to ancient carbonates

In  view  of  its  importance  for  geochemical  signal  preservation,  the  effect  of   diagenetic  modification  of  carbonate  chemistry  has  been  investigated.  Webb  et  al.   (2009)  established  that  during  the  neomorphism  of  calcite  after  original  aragonite  in   Pleistocene  scleractinian  coral  skeletons  in  a  vadose  meteoric  setting,  many  trace   elements    changed  as  expected  in  relative  and  absolute  concentrations  (e.g.  Sr,  Ba  and   U  were  lost  whereas  Mn  increased).  However,  it  was  also  found  that  the  REE  survived   this  near-­‐worst  case  scenario  of  diagenesis  (i.e.  neomorphism)  largely  intact.  For  this   reason,  the  REE  have  assumed  a  prevalent  role  in  attempts  at  reconstructing  aspects   of  the  ancient  environment  from  microbial  carbonates.  One  of  the  more  compelling   observations  for  the  survival  of  original  REE  is  the  interpretable  co-­‐variation  of  Fe-­‐ isotope  composition  with  REE  systematics  and  water  depth  (inferred  from  
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The synthesis of carbonates and related compounds from carbon dioxide

The synthesis of carbonates and related compounds from carbon dioxide

SYNTHESIS OF CARBAMATES Introduction Reaction of Alcohols with Sulfonyl Carbamates Introduction Synthesis of Phenyl N,N-Diethyl Carbamate Synthesis of n-Propyl N,N-Diethyl Carbamate Reac[r]

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The Li isotope composition of marine biogenic carbonates: patterns and mechanisms

The Li isotope composition of marine biogenic carbonates: patterns and mechanisms

Dellinger, M. and West, A.J. and Paris, G. and Adkins, J.F. and Pogge von Strandmann, Philip A.E. and Ullmann, C.V. and Eagle, R.A. and Freitas, P. and Bagard, M.-L. and Ries, J.B. and Corsetti, F.A. and Perez-Huerta, A. and Kampf, A.R. (2018) The Li isotope composition of marine biogenic carbonates: patterns and mechanisms. Geochimica et Cosmochimica Acta 236 , pp. 315-335. ISSN 0016-7037.

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To identify entities and their relationships. To describe entities using attributes, multivalued attributes, derived attributes, and key attributes.

To identify entities and their relationships. To describe entities using attributes, multivalued attributes, derived attributes, and key attributes.

The Enrollment table is not in 2NF, because the candidate key in the table is {ssn, courseId} and title is partially dependent on courseId. To normalize Enrollment into 2NF, you need to remove the non-key attributes that are dependent on the partial key from the relation and place them along with the partial keys in one or more separate tables. The

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3D seismic attributes analysis in reservoir characterization: the Morrison NE field & Morrison field, Clark County Kansas

3D seismic attributes analysis in reservoir characterization: the Morrison NE field & Morrison field, Clark County Kansas

Identification of potentially productive zones within the Viola limestone are based on instantaneous attributes analysis and amplitude anomalies. Using the workflow presented by this study could benefit future development plans in the Morrison and Morrison NE fields of east- central Clark County, KS as well as other locations in southwest and south-central Kansas. Identification of doublets forming at the top of the Viola imply a velocity anomaly associated with either the presence of hydrocarbons, the presence of more porous rock or a combination of the two. Low velocity anomalies increase the resolution of the seismic data which results in the doublets observed in the seismic trace data. Instantaneous phase and normalized amplitude attributes are helpful in identifying these velocity anomalies forming a doublet in the seismic trace data. The purpose of generating instantaneous phase and normalized amplitude attributes was to identify zones with hydrocarbon producing potential.
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Modification of Argillous Raw Materials by Additives Comprising Carbonates

Modification of Argillous Raw Materials by Additives Comprising Carbonates

A recalculation form an element composition to a content of oxide !0, SiO 2 leads to a conclusion, that !0:SiO 2 ratio is many times lower in the ceramics made from not modified clay as compared to clay, containing carbonates, which explains a detected decrease of mechanical strength in a case of modification. At the same time, it is detected, that surface structures are stronger, than internal ones, both in modified and not modified specimens. That fact can be explained by a partial pores’ formation in internal areas (visible decrease of specimens is detected) because of burning out of an organic component 19 . That data is supported
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Mechanisms of Surface Charge Modification of Carbonates in Aqueous Electrolyte Solutions

Mechanisms of Surface Charge Modification of Carbonates in Aqueous Electrolyte Solutions

In particular, we exploited the surface-enhanced infrared absorption phenomena of a model phosphoester on U(IV) nanoparticles for the first time to examine the heterogeneous reaction mec[r]

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Mechanisms of surface charge modication of carbonates in aqueous electrolyte solutions

Mechanisms of surface charge modication of carbonates in aqueous electrolyte solutions

It is argued that divalent cations Ca2+ and Mg2+ would result in positive and neutral complexes with stearic acid molecules, which may result in strongly bound stearic acid films, where[r]

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3D seismic attributes analysis to outline channel facies and reveal heterogeneous reservoir stratigraphy; Weirman Field, Ness County, Kansas, USA

3D seismic attributes analysis to outline channel facies and reveal heterogeneous reservoir stratigraphy; Weirman Field, Ness County, Kansas, USA

The wavelet transform allows the decomposition of a signal into various levels of scales or “resolution.” Different analyzing wavelets could be used in the decomposition process. Multi-resolution analysis has the potential to detect sub-seismic resolution channel sand bodies through some experimental attributes synthesis, which would also enhance subtle litho-facies related interpretive seismic patterns. Ojo and Sindiku (2003) used the seismic application of spectral decomposition to 3D seismic data from Southern Nigeria to map the geometry of incised channels. The spectral response of this study showed the lateral channel complex clearly and indicated fault trends. Wavelet transform is used in this study over the traditional Fourier transform function mainly because it has the ability to localize seismic information in the time- frequency domain simultaneously (Miao and Moon, 1999). The Fourier transform:
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Application of Seismic Attributes for Delineation of Channel Geometries and Analysis of Various Aspects in Terms of Lithological and Structural Perspectives of Lower Goru Formation, Pakistan

Application of Seismic Attributes for Delineation of Channel Geometries and Analysis of Various Aspects in Terms of Lithological and Structural Perspectives of Lower Goru Formation, Pakistan

If Spontaneous potential logs were available, then the thickness of the sands could be measured and it would be more beneficial for the deep studies. But to overcome this issue, we have applied spectral decomposition bands to fulfill our objective. Presence of sands is clearly proved from the seismic dominant frequency attribute. With the availability of more well data, the uncertainty level would be much reduced for compartmentalization of the channeled reservoir. The future well locations can be those which are shown by the blue arrows on domi- nant frequency attribute horizon slice (Figure 10).
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The Effects of Seismic Spectrum on Seismic Analysis

The Effects of Seismic Spectrum on Seismic Analysis

In the seismic computation of regenerative heat exchanger of Lingao II nuclear power plant, it is found that although two components are the same in structures, while they are put in different plants, the results differs far from each other. When analyzing these phenomenon in former time, we may think it’s caused by model itself, but the fact is not so. What kind of effect will the magnitude of seismic spectrum and the location change of the seismic spectrum peak value be on seismic computation results? In order to know these problems clearly, it is indispensable to analyze seismic computation results reasonably and heighten working efficiency.
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