Radar detection of gas seepage associated with oil and gas deposits

1992 ◽  
Vol 30 (3) ◽  
pp. 630-633 ◽  
Author(s):  
M. Skolnik ◽  
D. Hemenway ◽  
J.P. Hansen
Keyword(s):  
Oil And Gas ◽  
Radar Detection ◽  
Gas Seepage

Complex Subsurface Well Abandonments Using Relief Well Methodologies

2021 ◽  
Author(s):  
Jamie Dorey ◽  
Georgy Rassadkin ◽  
Douglas Ridgway
Keyword(s):  
Case Studies ◽  
Best Practice ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Gas Seepage ◽  
Cost Efficient ◽  
Well Abandonment ◽  
Efficient Option ◽  
Practice Methods

Abstract The field experience in the continental US suggests that approximately 33% of plug and abandonment operations are non-routine, and 5% require re-entry (Greer C.R., 2018). In some scenarios, the most cost-efficient option for the intervention is drilling an intercept well to re-enter the target well or multiple wells externally using advanced survey management and magnetic ranging techniques. This paper presents the methods applied of relief well methodologies from the planning to execution of a complex multiple-well abandonment project. Improvements in Active Magnetic Ranging sensor design and applications have improved the availability of highly precise tools for the purpose of locating and intercepting wellbores where access is not possible. These instruments were commonplace on relief well interventions, however, have found a new application in solving one of the major issues facing the oil and gas industry. Subsurface abandonments are a complex task that requires a robust methodology. In this paper, we describe the techniques that have been built upon the best practices from industry experience (ISCWSA WISC eBook). This paper also illustrates how the combination of advanced survey management, gyro surveying, and magnetic ranging can be used following the best industry practices for fast and cost-efficient non-routine plug and abandonment. Case studies of several abandonment projects are presented showing the various technical challenges which are common on idle and legacy wells. The projects include wells that are currently under the ownership of an operator and orphaned wells that have been insufficiently abandoned and left idle over many decades. The case studies outline how the application of relief well methodologies to the execution of complex sub surface interventions led to the successful outcomes of meeting environmental and government regulations for wellbore abandonment. This includes performing multiple zonal isolations between reservoirs, water zones and preventing oil and gas seepage to the surface. The projects and their outcomes prove economically viable strategies for tackling the growing issue of idle and orphaned wells globally in a fiscally responsible manner. Combining industry best practice methods for relief well drilling, along with the technological advancements in magnetic ranging systems is a solution for one of the largest dilemmas facing the oil and gas industry in relation to idle and orphaned wellbores. These applications allow previously considered impossible abandonments to be completed with a high probability of long-term success in permanent abandonment.

scholarly journals Methane emission and consumption at a North Sea gas seep (Tommeliten area)

2005 ◽  
Vol 2 (4) ◽  
pp. 1197-1241 ◽  
Author(s):  
H. Niemann ◽  
M. Elvert ◽  
M. Hovland ◽  
B. Orcutt ◽  
A. Judd ◽  
...  
Keyword(s):  
North Sea ◽  
Oil And Gas ◽  
Salt Diapir ◽  
Anaerobic Oxidation Of Methane ◽  
Cold Seeps ◽  
The North ◽  
Oxidation Of Methane ◽  
Phylogenetic Cluster ◽  
Carbonate Formation ◽  
Gas Seepage

Abstract. The North Sea hosts large coal, oil and gas reservoirs of commercial value. Natural leakage pathways of subsurface gas to the hydrosphere have been recognized during geological surveys (Hovland and Judd, 1988). The Tommeliten seepage area is part of the Greater Ekofisk area, which is situated above the Tommeliten Delta salt diapir in the central North Sea. In this study, we report of an active seep site (56°29.90'N, 2°59.80'E) located in the Tommeliten area, Norwegian Block 1/9, at 75 m water depth. Here, cracks in a buried marl horizon allow methane to migrate into overlying clay-silt and sandy sediments. Hydroacoustic sediment echosounding showed several venting spots coinciding with the apex of marl domes where methane is released into the water column and potentially to the atmosphere during deep mixing situations. In the vicinity of the gas seeps, sea floor observations showed small mats of giant sulphide-oxidizing bacteria above patches of black sediments and carbonate crusts, which are exposed 10 to 50 cm above seafloor forming small reefs. These Methane-Derived Authigenic Carbonates (MDACs) contain 13C-depleted, archaeal lipids indicating previous gas seepage and AOM activity. High amounts of sn2-hydroxyarchaeol relative to archaeol and low abundances of biphytanes in the crusts give evidence that ANaerobic MEthane-oxidising archaea (ANME) of the phylogenetic cluster ANME-2 were the potential mediators of Anaerobic Oxidation of Methane (AOM) at the time of carbonate formation. Small pieces of MDACs were also found subsurface at about 1.7 m sediment depth, associated with the Sulphate-Methane Transition Zone (SMTZ). The SMTZ of Tommeliten is characterized by elevated AOM and Sulphate Reduction (SR) rates, increased concentrations of 13C-depleted tetraether derived biphytanes, and specific bacterial Fatty Acids (FA). Further biomarker and 16S rDNA based analyses give evidence that AOM at the Tommeliten SMTZ is mediated by archaea belonging to the ANME-1b group and Sulphate Reducing Bacteria (SRB) most likely belonging to the Seep-SRB1 cluster. The zone of active methane consumption was restricted to a distinct horizon of about 20 cm. Concentrations of 13C-depleted lipid biomarkers (e.g. 500 ng g-dw-1 biphythanes, 140 ng g-dw-1 fatty acid ai-C15:0), cell numbers (1.5x108 cells cm-3), AOM and SR rates (3 nmol cm-3 d-1 in the SMTZ are 2-3 orders of magnitude lower compared to AOM zones of highly active cold seeps such as Hydrate Ridge or the Gulf of Mexico.

scholarly journals Oil and gas seepage offshore Georgia (Black Sea) – Geochemical evidences for a paleogene-neogene hydrocarbon source rock

2021 ◽  
Vol 128 ◽  
pp. 104995
Author(s):  
Thomas Pape ◽  
Martin Blumenberg ◽  
Anja Reitz ◽  
Georg Scheeder ◽  
Mark Schmidt ◽  
...  
Keyword(s):  
Source Rock ◽  
Black Sea ◽  
Oil And Gas ◽  
Hydrocarbon Source Rock ◽  
Gas Seepage

scholarly journals POLA ANOMALI GAYABERAT DAERAH TALIABU-MANGOLE DAN LAUT SEKITARNYA TERKAIT DENGAN PROSPEK MINYAK BUMI DAN GAS

2016 ◽  
Vol 12 (2) ◽  
pp. 65
Author(s):  
Saultan Panjaitan ◽  
Subagio Subagio
Keyword(s):  
Gravity Anomaly ◽  
Late Cretaceous ◽  
Middle Jurassic ◽  
Late Jurassic ◽  
Oil And Gas ◽  
Research Area ◽  
Black Shales ◽  
Reservoir Rocks ◽  
Gas Seepage ◽  
Anomaly Pattern

Anomali gayaberat di daerah penelitian merupakan anomali tertinggi di Indonesia, secara umum dikelompokkan ke dalam 2 (dua) satuan, yaitu: kelompok anomali gayaberat 160 mGal hingga 260 mGal membentuk pola rendahan/cekungan anomali, dan kelompok anomali gayaberat 260 mGal hingga 620 mGal membentuk pola tinggian anomali. Anomali sisa 0 mGal hingga 5 mGal membentuk tinggian anomali, diduga merupakan gambaran antiklin dengan diameter 10 – 15 kilometer. Perangkap struktur migas di daerah Minaluli, Madafuhi dan Lekosula Pulau Mangole berdekatan dengan lokasi rembesan migas, sehingga diusulkan untuk dilakukan pemboran eksplorasi. Sedangkan di Pulau Taliabu, Tolong, Pena, Samuya dan Teluk Jiko masih perlu dilakukan penambahan data. Batuan reservoir terdiri dari batupasir dan batugamping Formasi Tanamu berumur Kapur Akhir, menempati daerah beranomali sisa 0 mGal hingga 5 mGal, dengan rapat massa batuan sekitar 2.65 gr/cm³. Batuan induk adalah Formasi Buya umur Jura Tengah - Jura Akhir dari serpih hitam dengan rapat massa 2.71 gr/cm³, dan dapur migas terbentuk di sekitar daerah beranomali sisa -4 mGal hingga -28 mGal yang membentuk sub-cekungan di utara lepas pantai Pulau Mangole. Kata kunci: gayaberat, dapur minyak, cekungan, migas, serpih hitam, anomali sisa, rapat massa, antiklin, batuan induk. The gravity anomaly of research area is the highest anomaly in Indonesia, generally it can be grouped into 2 (two) units, that are 160 mGal up to 260 mGal anomaly groups formed low anomaly pattern, and 260 mGal up to 620 mGal anomaly groups formed high anomaly pattern. 0 mGal to 5 mGal residual anomaly formed high anomaly pattern, it is interpreted as anticline with diameter are 10-15 kilometers. The trap oil and gas structures of this area at Minaluli, Madafuhi, and Lekosula are near the location of oil and gas seepage, that is propose to explore and drill in that area. Whereas in Taliabu Island, Tolong, Pena, Samuya, and Jiko Gulf still need increasing datas. Reservoir rocks consist of sandstones and limestones of Tanamu Formations were Late Cretaceous age, that occupied the location of 0 mGal to 5 mGal residual anomaly with density 2.65 g/cm ³. Hostrock are Buya Formation are Middle Jurassic - Late Jurassic from black shales with density 2.71 g/cm³, and kitchen oil were formed in the area - 4 mGal to -28 mGal residual anomaly that formed low anomaly in the northern offshore of Mangole Island. Keyword: gravity, oil kitchen, basin, oil and gas, black shales, recidual anomaly, density, anticline, hostrocks.

scholarly journals Identifikasi Potensi Rembesan Mikro di Lapangan Migas Melalui Deteksi Mineral Lempung Menggunakan Citra Landsat 8 OLI/TIRS, Studi Kasus Lapangan Migas Cekungan Jawa Barat Bagian Utara

2018 ◽  
Vol 15 (1) ◽  
Author(s):  
Tri Muji Susantoro ◽  
Ketut Wikantika ◽  
Asep Saepuloh ◽  
Agus Handoyo Harsolumakso
Keyword(s):  
Clay Minerals ◽  
Oil And Gas ◽  
Short Wave ◽  
Grain Size Analysis ◽  
Landsat 8 ◽  
Landsat 8 Oli ◽  
Gas Field ◽  
Gas Seepage ◽  
Oil And Gas Field ◽  
Short Wave Infrared

Clay minerals in the oil and gas field have changed with an increase of the quantities in the middle of the oil and gas field and reduction in the edges. This reduction is the effect of micro seepage from oil and gas from the subsurface. The aims of the research is to identify the potential oil and gas seepage through clay mineral mapping. The data used where Landsat 8 OLI/TIRS with recording dated September 25, 2015. The method used in the mapping of clay minerals using the ratio of 1.55-1.75 µm (Short Wave Infrared 1) and 2.08-2.35 µm (Short Wave Infrared 2). The result of Landsat 8 OLI/TIRS data processing shows the potential of anomalies in edges of the oil and gas field. The anomaly is a change in the index value of clay minerals that tend to be lower with values 1.0 to 1.5 than the middle of oil and gas field with values 1.5 to 2.0. The potential pattern of the anomaly follows the border of the oil and gas field. Field surveys show that oil and gas field based on grain size analysis is dominated by clay-sized soil. The dominant clay minerals from X-Ray Diffraction analysis are smectite (56%) and kaolinite (6%).ABSTRAKMineral lempung di lapangan migas mengalami perubahan dengan terjadinya peningkatan kandungannya pada tengah lapangan migas dan pengurangan di tepinya. Pengurangan ini merupakan efek adanya rembesan mikro dari migas yang berasal dari bawah permukaan. Kajian ini bertujuan untuk mengidentifikasi adanya potensi rembesan migas melalui pemetaan mineral lempung. Adapun data yang digunakan adalah Landsat 8 OLI/TIRS dengan perekaman tanggal 25 September 2015. Metode yang digunakan pada pemetaan mineral lempung menggunakan perbandingan panjang gelombang 1.55-1.75 µm (Short Wave Infrared 1) dengan 2.08-2.35 µm (Short Wave Infrared 2). Hasil pengolahan data Landsat 8 OLI/TIRS menunjukkan adanya potensi anomali di tepi lapangan migas. Anomali tersebut berupa perubahan nilai indeks mineral lempung yang cenderung lebih rendah yaitu dengan nilai 1,0 – 1,5 dibandingkan lokasi di tengah lapangan yaitu dengan nilai 1,5 – 2,0.  Pola potensi anomali tersebut mengikuti batas tepi lapangan migas. Survei lapangan menunjukkan bahwa pada lapangan migas berdasarkan analisis ukuran butir didominasi oleh tanah berukuran lempung. Adapun mineral lempung yang dominan dari hasil analisis XRD berupa smektit (56%) dan terdapat kaolinit (6%).

Geochemistry of oil-and-gas seepage in Lake Baikal: towards understanding fluid migration system

2020 ◽  
Author(s):  
Evgeniya Egoshina ◽  
Michail Delengov ◽  
Olesya Vidishcheva ◽  
Elena Bakay ◽  
Natalya Fadeeva ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Organic Matter ◽  
Lake Baikal ◽  
Oil And Gas ◽  
Fluid Migration ◽  
Central Spot ◽  
Isotopic Analyses ◽  
Gas Seepage ◽  
Geochemical Studies ◽  
Thermogenic Methane

<p>Baikal is a Cenozoic syn-rift sedimentary basin with many surficial manifestations of distinct hydrocarbon system. Focused gas seeps, gas-hydrate accumulations, and various mud volcanoes are abundant all over the lake bottom and were recently studied in order to characterize an upward fluid migration from deeper strata. Highly concentrated oil seeps which can provide detailed information on basin fluid migration pathway configurations are mostly developed at the east coast and rift flank of Lake Baikal.</p><p>Herewith, we report results of detailed geochemical studies (gases, organic matter, bitumen, pore waters, and sediments) completed on samples collected from an area of active oil and gas seepage, asphalt/tar edifices and subbottom gas-hydrates occurrences located 18 km offshore the Gorevoy Utes cape (the eastern coast of the lake) at the depth of 850-950 m.</p><p>As a part of the Class@Baikal-2018 expedition, two high-resolution seismic profiles (total length of about 10 km) crossing the fluid discharge zone in transverse directions were acquired to locate 22 bottom sampling stations and to retrieve samples. Four more seismic lines and 12 sampling cores were collected during the follow up Class@Baikal-2019 cruise.</p><p>The highest concentrations of all gases and a fresh crude oil in sediments are characteristic for a spot of only about 500 m in diametre, marking a probable centre of the most intense deep fluid migration to the surface. The elemental composition characteristic of sampled oil was determined as follow: C=83.84%, H=10.67%, N=0.37%, and S<0.08% by wt. And its molecular compounds are 15% asphaltenes, 20% resins, 35% aromatic hydrocarbons, and 30% saturates.</p><p>High concentration of methane was also detected in samples at the distance from this central spot all around the studied field. According to isotopic analyses, this indicates lateral redistribution of thermogenic methane ongoing together with enhanced bacterial methane generation in surrounding sediments. δ13С of methane from the peripheries varies from -70.98 ‰ to -88.46 ‰, whereas the δ13С of methane from the central spot is heavier (up to -41.00 ‰). The high content of methane homologues (ethane and propane) and carbon dioxide is characteristic and indicative for all samples taken from the central spot. A few samples collected outside of the central zone demonstrated the high thermogenic methane concentration, carbon dioxide content and presence of some methane homologues as well. Most likely this points out at existence of locally permeable segments aside of main conduit, probably some fractures accompanying the central pathway. Interestingly, no fresh oil was found in those samples.</p><p>Rock-Eval pyrolysis, isotopic analyses and biomarker studies revealed that the source rocks for both hydrocarbon gases and oil are terrigeneous and contain predominant humic organic matter components (kerogen type III). These strata belong to different maturation stages, ranging from low-mature to peak-mature, which is well explained by the complex structure of the rift sedimentary infill and documented presence of local thermal anomalies in the region.</p><p>Results of geochemical studies are incorporated into an integrated model of source-to-surface fluid migration to explain the observed peculiarities of the Gorevoy Utes seepage area.</p>

scholarly journals A review of oil and gas seepage in the Nuussuaq Basin, West Greenland – implications for petroleum exploration

2020 ◽  
Author(s):  
Flemming G. Christiansen ◽  
Jørgen A. Bojesen-Koefoed ◽  
Gregers Dam ◽  
Troels Laier ◽  
Sara Salehi
Keyword(s):  
Structural Model ◽  
Oil And Gas ◽  
Source Rocks ◽  
Petroleum Exploration ◽  
Lateral Migration ◽  
West Greenland ◽  
Gas Seepage ◽  
Petroleum Generation ◽  
And Migration ◽  
Migration Pathways

The Nuussuaq Basin in West Greenland has an obvious exploration potential. Most of the critical elements are well documented, including structures that could form traps, reservoir rocks, seals and oil and gas seepage that documents petroleum generation. And yet, we still lack a full understanding of the petroleum systems, especially the distribution of mature source rocks in the subsurface and the vertical and lateral migration of petroleum into traps. A recently proposed anticlinal structural model could be very interesting for exploration if evidence of source rocks and migration pathways can be found. In this paper, we review all existing, mostly unpublished, data on gas observations from Nuussuaq. Furthermore, we present new oil and gas seepage data from the vicinity of the anticline. Occurrence of gas within a few kilometres on both sides of the mapped anticline has a strong thermogenic fingerprint, suggesting an origin from oil-prone source rocks with a relatively low thermal maturity. Petroleum was extracted from an oil-stained hyaloclastite sample collected in the Aaffarsuaq valley in 2019, close to the anticline. Biomarker analyses revealed the oil to be a variety of the previously characterised “Niaqornaarsuk type,” reported to be formed from Campanian-age source rocks. Our new analysis places the “Niaqornaarsuk type” 10 km from previously documented occurrences and further supports the existence of Campanian age deposits developed in source rock facies in the region.

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