NEW THINKING ON THE PETROLEUM PROSPECTIVITY OF DEEP MESOZOIC SEDIMENTS IN NEW ZEALAND BASINS

Geochemical studies, reinterpretation of early seismic data and information from new seismic surveys are extending the concept of economic basement for hydrocarbons in several New Zealand basins. Older Cretaceous and even Jurassic and Triassic rocks, previously considered to be 'basement' by petroleum explorationists, may have significance as petroleum prospects.Triassic–Jurassic Murihiku Supergroup sedimentary sequences are up to 15 km thick, and the upper parts are still of low metamorphic rank. Vitrinite reflectances and Hydrogen Indexes from Murihiku Supergroup coals sampled from outcrop and drillholes indicate good oil potential, and, together with rock porosity of up to 18%, suggest that the Murihiku Supergroup may be prospective.In the offshore Canterbury Basin, reinterpretation of seismic data has shown there is probably a thick sedimentary section below what was previously mapped as the regional basement horizon. This seismic interval can be related to a similar section developed in the adjacent Great South Basin where a mid-Cretaceous, rift- fill section of hydrocarbon-bearing rocks, drilled in the Kawau–1 well had good source and reservoir potential.In the onshore Canterbury Basin, a recent vibroseis survey has revealed apparent sedimentary section extending down to more than 4,000 m which might also be the expression of a mid-Cretaceous rift-fill section, similar to that in the nearby Great South Basin and in the formerly adjacent Taranaki Basin, or possibly the older Murihiku Supergroup. This potential for a mature oil and gas source section provides the basis for further exploration of the area.There are similar prospective sequences in several other New Zealand basins.

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PETROLEUM POTENTIAL OF THE GREAT SOUTH BASIN, NEW ZEALAND—NEW SEISMIC DATA IMPROVES IMAGING

The APPEA Journal ◽

10.1071/aj06008 ◽

2007 ◽

Vol 47 (1) ◽

pp. 145 ◽

Cited By ~ 8

Author(s):

C. Uruski ◽

C. Kennedy ◽

T. Harrison ◽

G. Maslen ◽

R.A. Cook ◽

...

Keyword(s):

New Zealand ◽

Seismic Data ◽

Oil And Gas ◽

Petroleum Industry ◽

Source Rocks ◽

Seismic Survey ◽

Recording Time ◽

Petroleum Potential ◽

South Basin ◽

Time Migration

Much of the Great South Basin is covered by a 30,000 km grid of old seismic data, dating from the 1970s. This early exploration activity resulted in drilling eight wells, one of which, Kawau–1a, was a 461 Bcf gas-condensate discovery. Three other wells had significant oil and gas shows; in particular, Toroa–1 had extensive gas shows and 300 m oil shows. Cuttings are described in the geological logs as dripping with oil. The well was never tested due to engineering difficulties, meaning that much of the bore was accidentally filled with cement while setting casing.In early 2006, Crown Minerals, New Zealand’s petroleum industry regulating body, conducted a new 2D seismic survey in a previously lightly surveyed region across the northern part of the Great South Basin. While previous surveys were generally recorded for five seconds, sometimes six, with up to a 2,500-metre-long cable, the new survey, acquired by CGG Multiwave’s Pacific Titan, employed a 6,000-metre-long streamer and recorded for eight seconds.The dataset was processed to pre-stack time migration (PreSTM) by the GNS Science group using its access to the New Zealand Supercomputer. Increasing the recording time yielded dividends by more fully imaging, for the first time, the nature of rift faulting in the basin. Previous data showed only the tops of many fault blocks. The new data show a system of listric extensional faults, presumably soling out onto a mid-crust detachment. Sedimentary reflectors are observed to seven seconds, implying a thickness of up to 6,000 m of section, probably containing source rock units. The rotated fault blocks provide focal points for large compaction structures. The new data show amplitude anomalies and other features possibly indicating hydrocarbons associated with many of these structures. The region around the Toroa–1 well was typified by anomalously low velocities, which created a vertical zone of heavily attenuated reflections, particularly on intermediate processing products. The new data also show an amplitude anomaly at the well’s total depth (TD) which gives rise to a velocity push-down.Santonian age coaly source rocks are widespread and several reservoir units are recognised. The reservoir at Kawau–1a is the extensive Kawau Sandstone, an Early Maastrichtian transgressive unit sealed by a thick carbonate-cemented mudstone. In addition to the transgressive sandstone target, the basin also contains sandy Eocene facies, and Paleogene turbidite targets may also be attractive. Closed structures are numerous and many are very large with potential to contain billion barrel oil fields or multi-Tcf gas fields.

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Seismogeological characteristics and oil-and-gas prospects of the cambrian sediments within the Vilyui hemisyneclise

Недропользование. Горное дело. Направления и технологии поиска, разведки и разработки месторождений полезных ископаемых. Экономика. Геоэкология: Материалы XVI международной конференции (20-24 апреля 2020, Новосибирск) ◽

10.18303/b978-5-4262-0102-6-2020-007 ◽

2020 ◽

Author(s):

Igor A. Gubin ◽

◽

Alexey E. Kontorovich ◽

Andrey M. Fomin ◽

◽

...

Keyword(s):

Seismic Data ◽

Structural Model ◽

Oil And Gas ◽

Sedimentary Cover ◽

Data Interpretation ◽

Hydrocarbon Generation ◽

Deep Drilling ◽

Middle Cambrian ◽

Seismic Surveys ◽

Gas Source

Based on geological and geophysical data, such as deep drilling, well logging, seismic surveys CDP-2D, DSS, SK-VSP a sedimentary cover structural model of the Vilyui hemisineclise to the lower Cambrian roof is constructed. According to seismic data interpretation, the ubiquitous development of the oil and gas source Kuonamka formation is predicted within the internal boundaries of the Vilyui hemisyneclise, where it formed an extensive center of hydrocarbon generation. Clinoform-built Middle Cambrian rocks (Maysky stage) overlie Kuonamka formation. The reservoirs development in the Maysky stage rocks is substantiated, a forecast map of porosity coefficients is generated.

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Hydrocarbon systems of the Crimean-Caucasian segment of the Alpine folded system

Georesursy ◽

10.18599/grs.2021.4.3 ◽

2021 ◽

Vol 23 (4) ◽

pp. 21-33

Author(s):

Vagif Kerimov ◽

Nurdin Yandarbiev ◽

Rustam Mustaev ◽

Andrey Kudryashov

Keyword(s):

Oil And Gas ◽

Foreland Basin ◽

Gas Content ◽

Hydrocarbon Generation ◽

Gas Source ◽

Coal Petrology ◽

Geochemical Studies ◽

Cenozoic Sediments ◽

Oil Formation ◽

Residual Potential

The article is devoted to the generation and accumulation systems in the territory of the Crimean-Caucasian segment of the Alpine folded system. An area of prolonged and stable sagging in the Mesozoic and Cenozoic – the Azov-Kuban Trough, which is a typical foreland basin – is distinguished within this segment. According to the results of geological and geochemical studies and modelling, depocentres are identified in this area, consolisated in four generative and accumulative hydrocarbon systems: Triassic-Jurassic, Cretaceous, Eocene and Maikop. Chemical-bitumenological, pyrolytic and coal petrology analysis of rock samples were carried out to assess geochemical conditions of oil and gas content in Meso-Cenozoic sediments. The modelling results made it possible to study and model the elements and processes of hydrocarbon systems in the Meso-Cenozoic in the Western Crimean-Caucasian region. It has been established that the extended catagenetic zoning is typical for these areas, which is caused by high rates of sedimentation and sagging, and large thicknesses of oil-bearing sediments in the source of oil formation, accordingly. The degree of organic matter depletion characterized the residual potential of the oil and gas source strata, was investigated. It is important for predicting and assessing the possibility of hydrocarbon generation.

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New style of honeycomb structures revealed on 3D seismic data indicate widespread diagenesis offshore Great South Basin, New Zealand

Marine and Petroleum Geology ◽

10.1016/j.marpetgeo.2017.05.035 ◽

2017 ◽

Vol 86 ◽

pp. 140-154 ◽

Cited By ~ 11

Author(s):

C.K. Morley ◽

A. Maczak ◽

T. Rungprom ◽

J. Ghosh ◽

J.A. Cartwright ◽

...

Keyword(s):

New Zealand ◽

Seismic Data ◽

3D Seismic ◽

South Basin ◽

Honeycomb Structures ◽

3D Seismic Data

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THE EAST COAST BASIN OF NEW ZEALAND, AN EMERGING PETROLEUM PROVINCE

The APPEA Journal ◽

10.1071/aj04043 ◽

2005 ◽

Vol 45 (1) ◽

pp. 563 ◽

Cited By ~ 3

Author(s):

C.I. Uruski ◽

B.D. Field ◽

R. Funnell

Keyword(s):

New Zealand ◽

Seismic Data ◽

Oil And Gas ◽

East Coast ◽

Data Set ◽

Sequence Stratigraphic ◽

Large Structures ◽

Oil Generation ◽

Wide Range ◽

Reservoir Facies

More than 300 oil and gas seeps are known in the onshore East Coast Basin of North Island, New Zealand. Spectacular geological structures have been explored by more than 40 wells, only three of which have been offshore. Results are tantalising, with 70% of wells yielding oil or gas shows. Westech’s two gas discoveries onshore at Kauhauroa and Tuhara in northern Hawkes Bay remain un-developed at present.Strong gas shows were encountered in both open-file wells drilled offshore and elevated gas readings were recorded in the recent Tawatawa–1 well, but reservoir quality was poor.Nevertheless, good reservoir facies are abundant in the East Coast Basin. A wide range of Miocene and Pliocene sands and limestones, with porosities of 20% and above are known from outcrop and wells. But, modern, good quality seismic data are essential to allow sequence stratigraphic interpretation and a reasonable likelihood of predicting the distribution of reservoir facies. As part of its program to stimulate exploration in New Zealand, the NZ government is commissioning a new 4,000 km, highquality 2D seismic data set with the intention of making it freely available to interested exploration companies by mid-2005.The very thick sedimentary succession, the presence of direct hydrocarbon indicators on seismic data, the strong gas shows in wells drilled offshore and the reasonable expectation of oil generation and expulsion into numerous large structures with good reservoir facies combine to make the offshore East Coast Basin an attractive exploration venue.

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OIL EXPLORATION IN NEW ZEALAND—PAST AND FUTURE TRENDS

The APPEA Journal ◽

10.1071/aj70005 ◽

1971 ◽

Vol 11 (1) ◽

pp. 35

Author(s):

H. R. Katz

Keyword(s):

New Zealand ◽

Oil And Gas ◽

East Coast ◽

Small Scale ◽

Expiry Date ◽

Seismic Surveys ◽

The North ◽

Geophysical Surveys ◽

Increased Activity ◽

Commercial Field

The earliest lease for oil prospecting was granted in 1865, and the first bore went down in 1866. Since then and up to 1936, 130 wells were drilled mainly in Taranaki, the East Coast of the North Island and the West Coast of the South Island. No commercial field was discovered, but some oil and gas was found sporadically — sometimes enough for local small-scale consumption — which kept interests alive.The Petroleum Act in 1937 vested all petroleum prospecting and mining rights in the Crown; with minor modification, it has regulated exploration to the present day. The war-time years saw renewed activity by several major companies; the first seismic surveys were undertaken, and some 20 holes were drilled. But except intermittent, small production from the Moturoa field in New Plymouth (the she of the first well of 1866), no further success was achieved and exploration ceased after 1944. The present period of activity started in 1955. On land the Kapuni gas-condensate field was discovered in 1959, and offshore the much larger Maui field in 1969. Both are in the Taranaki Basin which, having the best prospects in the country, has also received far more attention than other areas.Land operations sharply decreased after 1965 when Shell and BP, the only majors with on-land interests, began concentrating on new offshore holdings while still retaining their original big land concessions. Amongst the increasing number of independents continued regrouping of interests, farm deals, etc., have become common, and these companies account for nearly all activity on land during more recent years. Practically all drilling after 1965, which from a 5,686 ft. low in 1966 increased to 28,741 ft. in 1969 and 16,952 ft. in 1970 (the smaller 1970 figure is mainly due to rig shortage), was done by companies other than Shell-BP, many of them newcomers. Since to these the more promising prospects have been unavailable, exploration has noticeably shifted to areas of lesser and even marginal prospects.Concessions have for a number of years covered all lands of even remotest possibilities; the total area leased is around 50,000 sq. miles.Offshore the first concessions were granted in 1965; in 1970 they covered 384,547 sq. miles. Extensive geophysical surveys followed nearly immediately, and the first well was spudded by Esso in October, 1968. The second well, by Shell in March, 1969, discovered the large Maui field, later confirmed by two step-outs. Up to November 1970, 10 offshore wells with an aggregate footage of 101,181 ft. were drilled.I he only offshore rig now has left but additional targets are already established, and more will undoubtedly be after seismic surveys presently in course. Offshore drilling is expected to resume as soon as possible, particularly in concessions soon to expire. In large areas only recently granted, however, excessive water depth of up to 1000 m will prevent drilling for probably many years.On land, the tendency for wider participation in joint ventures is likely to continue. Increased activity by small operators is expected, as domestic rig availability has improved and many concessions are nearing expiry date. New licences to be granted over Greymouth and Canterbury areas which have drawn many competing applications should further stimulate the picture. Since Shell-BP in 1970 finally farmed out their large block in Taranaki which still holds the best prospects and many unexplored features, new operations are expected also there before expiry in 1973; BP-Shell's East Coast holdings expire in 1972 and the future of these two blocks which since 1955 have been in the hands of the same consortium, will probably be most important to further developments in New Zealand.

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Prospects of oil and gas potential of the Pripyat trough carbonate complex

Georesursy ◽

10.18599/grs.2019.2.110-116 ◽

2019 ◽

Vol 21 (2) ◽

pp. 110-116

Author(s):

Natalya P. Fadeeva ◽

Elena N. Poludetkina ◽

Yury A. Petrichenko

Keyword(s):

Oil And Gas ◽

Carbonate Complex ◽

Oil And Gas Exploration ◽

Oil And Gas Fields ◽

Gas Source ◽

Geological Work ◽

Gas Fields ◽

Geochemical Studies ◽

Gas Potential ◽

Carbonate Complexes

Oil-geological work in the Pripyat oil and gas basin has been going on for over 70 years; to date, more then 80 oil and gas fields have been discovered there, but due to the ever-growing need for energy consumption, work on the identification of new resources is constantly continuing. Geochemical studies of oil deposits, as well as 3D modeling of the processes of generation, emigration and accumulation of hydrocarbons, taking into account all risk factors, made it possible to identify promising objects for oil and gas exploration in the subsalt and intersalt carbonate complexes. The calculated scales of generation, emigration and accumulation of hydrocarbons, carried out as a result of geochemical and basin modeling, turned out to be comparable and showed that the oil and gas source potential of the Devonian sediments of the Pripyat trough was realized by no more than one third.

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