Seismic analysis of paleotopography and stratigraphic controls on total organic carbon: Rich sweet spot distribution in the Woodford Shale, Oklahoma, USA

2017 ◽  
Vol 5 (1) ◽  
pp. T33-T47 ◽  
Author(s):  
Lennon Infante-Paez ◽  
Luis-Felipe Cardona ◽  
Brenton McCullough ◽  
Roger Slatt
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Sea Level ◽  
Seismic Analysis ◽  
Sweet Spot ◽  
Woodford Shale ◽  
Subaerial Exposure ◽  
Unconformity Surface ◽  
Topographic Relief ◽  
Sweet Spots

The Devonian Woodford Shale is a prolific unconventional resource shale for oil and gas. Like many such shales, the Woodford sits atop an unconformity on the surface of underlying carbonate rocks (mainly the Hunton Group in this case). There is variable topographic relief on the unconformity surface due to incised valleys, cave collapse, and/or karst formation during periods of subaerial exposure resulting from eustatic sea-level fluctuations. Anomalously high thicknesses of the Woodford, with relatively high total organic carbon (TOC), can form within topographic depressions on the unconformity surface, giving rise to potential “sweet spots” as drilling targets. It is likely that the topographic relief that formed during subaerial exposure created areas of restricted marine circulation (or possibly hypersaline lakes) during an early fall in the sea level, and thus, localized anoxic depositional environments conducive to preservation of organic matter (TOC). Seismic analysis, calibrated with well logs and cuttings, of two areas on the Cherokee Platform in Oklahoma were completed to test the discontinuous and isolated distribution, vertically and horizontally, of the TOC. In one area, the TOC ranged up to 10 wt.% and in the other area, up to 13 wt.%. Seismic inversion and attribute analysis demonstrated the patchy distribution of the TOC vertically and laterally in both areas. These patchy, discontinuous distribution spotlights areas where TOC was preserved (in the minibasins), and point to potential sweet-spot locations. The delineation of organic-rich sweet spots was accomplished by integrating geologic, geochemical, and geophysical data in probabilistic neural networks obtaining seismic impedance-derived TOC that was mapped across different locations in the Cherokee Platform.

Correlation of chemostratigraphy, total organic carbon, sequence stratigraphy, and bioturbation in the Woodford Shale of south-central Oklahoma

2018 ◽  
Vol 6 (1) ◽  
pp. SC43-SC54
Author(s):  
Sabrina M. Coleman ◽  
Douglas W. Jordan
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Sequence Stratigraphy ◽  
Algal Blooms ◽  
Bottom Water ◽  
Woodford Shale ◽  
X Ray ◽  
South Central ◽  
Technological Advances ◽  
Water Conditions

Technological advances in handheld X-ray fluorescence (HHXRF) have been instrumental in demonstrating the utility of chemostratigraphic data to create higher order sequence stratigraphic interpretations. This study seeks to identify the correlation between chemostratigraphy, total organic carbon, sequence stratigraphy, and bioturbation in the Woodford Shale of south-central Oklahoma using HHXRF and X-ray diffraction technologies. The use of multiproxy correlations allows for higher confidence identifying lateral changes in the Woodford Shale. Elemental data collected through HHXRF can be used as proxies to better understand the depositional environment of a formation. Titanium, Zr, K, and Al are all proxies for transgression and regression. Silica is associated with so many different elements that Si alone does not provide useful information; however, the ratio of Si/Al coupled with detrital proxies can give information on the presence of possible algal blooms, continentally derived sediment, or hiatal surfaces. Furthermore, relationships between other elements can give further understanding to bottom-water conditions at the time of deposition. This study examines the relationships between Mo, V, Ni, and P along with other elements and laboratory-collected data to further understand the bottom-water conditions during deposition of the organic-rich muds that make up the Woodford Shale in south-central Oklahoma. To some extent, it is then possible to correlate these higher-resolution understandings to open-hole well logs to increase our understanding, where the core is unavailable.

scholarly journals ANALISIS LOG TOC PASSEY DAN PENYEBARAN SERPIH PINIYA MENGGUNAKAN METODE SEISMIK INVERSI, CEKUNGAN AKIMEUGAH

2019 ◽  
Vol 23 (2) ◽  
pp. 29
Author(s):  
Winda Putri Anggraeni ◽  
Jarot Setyowiyoto ◽  
Ferian Anggara
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Sweet Spot ◽  
Shallow Marine ◽  
Organic Shale

Cekungan Akimeugah memiliki potensi hidrokarbon dengan adanya beberapa rembesan minyak dan gas bumi disekitar daerah penelitian. Hal ini mengindikasikan adanya sistem minyak dan gas bumi yang bekerja pada daerah tersebut. Serpih Piniya merupakan salah satu formasi yang berpotensi menjadi batuan induk sekaligus batuan reservoar yang baik. Batuan induk yang mengandung hidrokarbon ditentukan oleh kuantitas material organik (Total Organic Carbon). Untuk itu, perlu diketahui kuantitas material organik (TOC) serta penyebaran dari Serpih Piniya.Serpih Piniya disusun oleh litologi dominan serpih dengan sisipan batulanau dan batupasir. Formasi ini diendapkan pada lingkungan laut dangkal (shallow marine) dengan asosiasi fasies offshore transition hingga offshore. Jumlah kuantitas material organik (TOC) dari data sampel sebesar 0.552 wt% termasuk ke dalam kategori batuan induk yang bersifat cukup (fair). Tipe kerogen Serpih Piniya adalah tipe II – III yang dapat menghasilkan hidrokarbon minyak dan gas. Litofasies serpih yang dapat menghasilkan hidrokarbon adalah organic shale. Interval organic shale terdapat pada sumur AK-6 sebanyak 46 zona dan sumur AK-9 sebanyak 34 zona. Perhitungan TOC Passey menghasilkan nilai TOC rata-rata sebesar 0.527 wt% menandakan Serpih Piniya berada pada kategori batuan induk yang bersifat cukup.Penyebaran nilai TOC menggunakan seismik inversi untuk mengetahui model geologi bawah permukaan. Penyebaran nilai TOC tinggi ditandai dengan nilai impedansi akustik yang rendah, area tersebut terletak pada bagian rendahan daerah penelitian. Area sweet spot secara umum berada disekitar sumur AK-2, area tersebut memiliki nilai TOC berkisar 0.552 wt% dengan ketebalan Serpih Piniya kurang lebih sebesar 1200 m.

scholarly journals INTEGRATED OF GEOMECHANICS WELLBORE STABILITY & SWEET SPOT ZONE ANALYSIS TO UNCONVENTIONAL WELL DRILLING OPTIMIZATION

PETRO ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 21
Author(s):  
Allen Haryanto Lukmana
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Shear Failure ◽  
Horizontal Stress ◽  
Wellbore Stability ◽  
Brittleness Index ◽  
Sweet Spot ◽  
Collapse Pressure ◽  
Laboratory Test Results ◽  
Shale Formation

<strong><em>Abstract </em></strong>Central Sumatra Basin is one of the largest hydrocarbon producer basins in Indonesia. The largest hydrocarbons accumulation in this basin does not rule out the possibility of hydrocarbons also trapped in shale source rock. The potential for hydrocarbon shale is in the Brown Shale Pematang Group layer. The obstacle to development is the depth of the Brown Shale layer so deep that further case studies are needed. This study aims to analyze the geomechanical wellbore stability modelling for drilling and determination sweet spot zone supported by x-ray diffraction (XRD), brittleness index (BI), total organic carbon (TOC) analysis. The geomechanical wellbore stability modelling based on pore pressure, shear failure gradient/collapse pressure, fracture gradient, normal compaction trend, minimum horizontal stress, maximum horizontal stress and overburden gradient analysis. Brittleness index considers each parameter from XRD data which dominantly contains clay, quartz, and calcium. Based on XRD analysis of shale samples from Limapuluh Koto Area, it showed that the samples included the brittle shale group because of the dominant quartz, while the samples from Kiliran Jao were shale brittle because of dominant carbonate (carbonate-rich). From laboratory test results of 8 rock samples from Brown Shale Formation outcrop in Limapuluh Koto Area, it was obtained total organic carbon (TOC) value is 4-17% (average 8%). The shale thickness estimated &gt; 30 m, the brittleness index shale estimated 0.71, and the gradient of over-pressure on Brown Sahle Pematang Group estimated 0.57 psi/ft &amp; 0.53 psi/ft from log data analysis. So the output of this results the study is expected to get stable borehole, minimum of non-productive time (NPT), the problem when drilling such as caving and sloughing. Based on (Mt, 2013), the prospect criteria results can be concluded that the Brown Shale Formation has good unconventional hydrocarbon shale potential. It can be carried out with further research.

Sweet-spot mapping of the Goldwyer Formation through formation evaluation and property modelling in the Canning Basin, Barbwire Terrace case study

2017 ◽  
Vol 57 (2) ◽  
pp. 692
Author(s):  
Munther Alshakhs ◽  
Reza Rezaee
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Source Rock ◽  
Water Saturation ◽  
Total Porosity ◽  
Resource Assessment ◽  
Estimation Methods ◽  
Sweet Spot ◽  
Canning Basin ◽  
Hydrocarbon Resource

The Goldwyer Formation of the Canning Basin has been regarded as a highly prospective shale petroleum play. This study assesses the potential prospectivity of this source rock as an unconventional hydrocarbon resource via property modelling. Considering the sparsity of wells penetrating the Middle Ordovician Goldwyer across the vast under-explored area of the Canning Basin, a basin-wide study of the source rock is not justified. Due to a higher well density, assessment of the Goldwyer Formation within the Barbwire Terrace, a sub-division of the Canning Basin, is carried out instead. This assessment includes the estimation of key shale play properties, such as, total organic carbon, total porosity, water saturation, and brittleness. Each property was estimated from available well wireline log data by testing multiple estimation methods. Total organic carbon values were derived from multiple regressions of different well data. A simplified Archie’s equation was used to estimate water saturation. Density porosity method was used for total porosity estimations. Sonic data along with density were utilised to estimate the brittleness index. Each property was then modelled across the Barbwire Terrace, which provided geostatistical estimates on the propagation of each parameter. In order to generate sweet spot maps, averaged maps of the properties were combined in a weighted manner. In the model, the Goldwyer Formation was divided into three layers based on dominant lithology. The uppermost shale dominated layer was predicted by the model to be the most prospective stratigraphic zone. The sweet spot maps highlight the southern flanks of the northern and western part of the Barbwire Terrace as the highest prospective geographic locations. This approach attempts to simplify the complexity of unconventional resource assessment, and has provided a single product evaluating the prospectivity of the Goldwyer as a hydrocarbon resource.

Phanerozoic Oxygen

2017 ◽  
Author(s):  
Donald Eugene Canfield
Keyword(s):  
Oxygen Consumption ◽  
Organic Carbon ◽  
Sea Level ◽  
Time Scale ◽  
Atmospheric Oxygen ◽  
Sea Level Change ◽  
Oxygen Production ◽  
Level Change ◽  
History Of ◽  
Geologic Processes

This chapter discusses the modeling of the history of atmospheric oxygen. The most recently deposited sediments will also be the most prone to weathering through processes like sea-level change or uplift of the land. Thus, through rapid recycling, high rates of oxygen production through the burial of organic-rich sediments will quickly lead to high rates of oxygen consumption through the exposure of these organic-rich sediments to weathering. From a modeling perspective, rapid recycling helps to dampen oxygen changes. This is important because the fluxes of oxygen through the atmosphere during organic carbon and pyrite burial, and by weathering, are huge compared to the relatively small amounts of oxygen in the atmosphere. Thus, all of the oxygen in the present atmosphere is cycled through geologic processes of oxygen liberation (organic carbon and pyrite burial) and consumption (weathering) on a time scale of about 2 to 3 million years.

CHARACTERISATION OF DISSOLVED ORGANIC CARBON (DOC) LEACHED FROM LEAVES IN WATER

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Markus Heryanto Langsa
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Total Organic Carbon ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography ◽  
Chromatography Mass Spectrometry ◽  
Pinus Radiate

<p>Penelitian ini bertujuan untuk menentukan senyawa organik khususnya organic karbon terlarut (DOC) dari dua spesies daun tumbuhan (<em>wandoo eucalyptus </em>and <em>pinus radiate, conifer</em>) yang larut dalam air selama periode 5 bulan leaching eksperimen. Kecepatan melarutnya senyawa organic ditentukan secara kuantitatif dan kualitatif menggunakan kombinasi dari beberapa teknik diantaranya Total Organic Carbon (TOC) analyser, Ultraviolet-Visible (UV-VIS) spektrokopi dan pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).</p><p>Hasil analisis DOC dan UV menunjukkan peningkatan yang tajam dari kelarutan senyawa organic di awal periode pengamatan yang selanjutnya berkurang seiring dengan waktu secara eksponensial. Jumlah relatif senyawa organic yang terlarut tergantung pada luas permukaan, aktifitas mikrobiologi dan jenis sampel tumbuhan (segar atau kering) yang digunakan. Fluktuasi profil DOC dan UV<sub>254</sub> disebabkan oleh aktifitas mikrobiologi. Diperoleh bahwa daun kering lebih mudah terdegradasi menghasilkan senyawa organic dalam air dibandingkan dengan daun segar. Hasil pyrolysis secara umum menunjukkan bahwa senyawa hidrokarbon aromatic dan fenol (dan turunannya) lebih banyak ditemukan pada residue sampel setelah proses leaching kemungkinan karena adanya senyawa lignin atau aktifitas humifikasi mikrobiologi membuktikan bahwa senyawa-senyawa tersebut merupakan komponen penting dalam proses karakterisasi DOC.</p>

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