Integrated geologic, geophysical, and petrophysical data to construct full field geologic model of Cambrian-Ordovician and Upper Cretaceous reservoir formations, Central Western Sirte Basin, Libya

2019 ◽  
Vol 7 (1) ◽  
pp. T21-T37
Author(s):  
Abdalla A. Abdelnabi ◽  
Yousf Abushalah ◽  
Kelly H. Liu ◽  
Stephen S. Gao
Keyword(s):  
Upper Cretaceous ◽  
Thickness Variation ◽  
Reservoir Properties ◽  
Full Field ◽  
Vertical Heterogeneity ◽  
Field Static ◽  
Original Oil In Place ◽  
Well Data ◽  
Sirte Basin

The Cambrian-Ordovician and Upper Cretaceous formations, which are the main oil-producing formations in the central Sirte Basin, are structurally complex. The lateral and vertical heterogeneity of the reservoir formations is not well-understood, which negatively affects the performance of the reservoirs. We constructed efficient full-field static models that incorporate the lateral and vertical variation of those reservoir formations by integrating geologic and geophysical data. We determined lithology and reservoir properties by selecting appropriate petrophysical techniques that suit the available well data and overcome issues with unreliable well-log measurements. In the process of building structural models, defining and mapping the base of the Cambrian-Ordovician Gargaf Formation was very challenging because wells did not penetrate the basal formation, and the quality of the seismic data decreases with depth. Therefore, we applied techniques of adding isochore maps of the overlying Upper Cretaceous of the Bahi and Waha Formations to map basal contact and determine the thickness of the Gargaf Formation for the first time in the area. The constructed isochore maps showed the thickness variation and the distributions of the Bahi and Waha Formations and explained the influence of Gargaf paleotopography and faults on them. The fault models combined with facies and property models suggested an interconnection among the three main reservoirs. They also indicated that the quality of the Waha reservoir enhances as the lithology varies from limestones to calcareous sandstones, whereas the quality of the Gargaf reservoir was primarily controlled by fractures. The total estimate of the original oil in place with the largest contribution of hydrocarbon volume from the Waha Formation was [Formula: see text] stock tank barrel. The created model with a fine-scale geocellular covering an area of [Formula: see text] is unique to the study area and it can be updated and refined at any time with new data production and drilling activities.

Development of a Performance Assessment Model (PAM) for High Complexity Non-Conventional Reservoirs

2012 ◽  
Author(s):  
Juan M. Riaño Caraza ◽  
Fernando S. Flores Avila ◽  
Iván Faría Rojas ◽  
Luis E. Brito Rodríguez
Keyword(s):  
Performance Assessment ◽  
Assessment Model ◽  
Great Level ◽  
Vertical Heterogeneity ◽  
Original Oil In Place ◽  
Geological Complexity ◽  
Integral Complexity ◽  
A Current ◽  
A Performance

Chicontepec is one of the areas with the largest volume of original oil in place in Mexico; however, after more than 30 years of operation, its development has been very limited due to the high geological complexity and low rock quality of their reservoirs. The reservoirs are found in layered sequences of sediments deposited in turbiditic environments which have suffered different degrees of diagenesis, there is a great level of vertical heterogeneity and a very limited level of lateral continuity. The permeability of the reservoir area is in the range of 0.1 to 5 md, depending on the location and degree of diagenesis, with this level of permeability most wells require hydraulic fracturing to be produced economically. The volume of oil originally in place according to the latest certifications is around 130 billion barrels, of which to this date have been produced 200 MMbls, which represents a current recovery factor of 0.15%. In order to accelerate the development of reserves PEMEX has diversified efforts assigning some areas to other companies. This will provide greater ability to assess best practices and technologies. To evaluate the efforts of companies a performance assessment model was designed, which takes into account the integral complexity of each area to be fair in comparing the results obtained for the different areas. The aim of this paper is to describe the methodology used in the developing of the performance evaluation and integral complexity characterization models.

The Paleozoic prospectivity of the Browse Basin, Australia

2020 ◽  
Vol 60 (2) ◽  
pp. 685
Author(s):  
Said Amiribesheli ◽  
Joshua Thorp ◽  
Julia Davies
Keyword(s):  
Seismic Data ◽  
Inversion Algorithm ◽  
Reservoir Properties ◽  
Depth Migration ◽  
Canning Basin ◽  
Petroleum Systems ◽  
Amplitude Versus Offset ◽  
Long Offset ◽  
Well Data

Most of the discovered hydrocarbons in the Browse Basin occurred within the Mesozoic intervals, while deeper Paleozoic sequences have been seldom explored. Lack of Paleozoic exploration in the Browse Basin has been attributed to the lack of well penetrations, poor understanding of the petroleum systems and paucity of seismic data. The onshore Canning Basin with several commercial fields and discoveries is the most appropriate analogue for understanding the Paleozoic sequences in the region. With the integration of geophysical data (i.e. gravity, magnetic and seismic), well data and geology, the Paleozoic prospectivity of the Browse Basin can be further enlightened. Modern long offset (8 m) Vampire 2D seismic data were acquired by Searcher to address some of the complex challenges in the Browse Basin. Reservoir quality of the Brewster Formation, volcanic discrimination within the Plover Formation and identification of deeper Triassic and Paleozoic plays are some examples of these challenges in the Browse Basin. Recently Searcher reprocessed this regionally important Vampire 2D seismic dataset that ties to 60 wells. The broadband pre-stack depth migration reprocessed data were inverted to extract three petro-elastic properties of acoustic impedance, Vp/Vs and density by three-term amplitude versus offset inversion algorithm to improve imaging of deeper plays and delineate reservoir properties. This paper discusses how several potential Paleozoic reservoir-seal pairs can be identified in the Browse Basin by utilising the integration of Vampire 2D seismic data, quantitative interpretation products, regional geology and knowledge of the Canning Basin’s fields and discoveries. Previously there was little exploration of Paleozoic plays because they could not be imaged on seismic data. The potential Paleozoic reservoirs identified in this study include Permo-Carboniferous subcrop, Carboniferous-Devonian anticline and Carboniferous-Devonian rollover plays.

Stochastic inversion by trace matching for carbonate reservoir property prediction: A Mishrif Reservoir case study

2019 ◽  
Vol 38 (1) ◽  
pp. 27-34 ◽  
Author(s):  
Sara R. Grant ◽  
Matthew J. Hughes ◽  
O. J. Olatoke ◽  
Neil Philip
Keyword(s):  
Seismic Data ◽  
Carbonate Reservoir ◽  
Inversion Process ◽  
Reservoir Properties ◽  
Stochastic Inversion ◽  
Large Numbers ◽  
Well Data ◽  
Established Technique

Estimation of reservoir properties and facies from seismic data is a well-established technique, and there are numerous methods in common usage. Our 1D stochastic inversion process (ODiSI), based on matching large numbers of pseudowells to color-inverted angle stacks, produces good estimations of reservoir properties, facies probabilities, and associated uncertainties. Historically, ODiSI has only been applied to siliciclastic reservoir intervals. However, the technique is equally suited to carbonate reservoirs, and ODiSI gives good results for the Mishrif Reservoir interval in the Rumaila Field in Iraq. Of course, a thorough awareness of the quality of all input well data and detailed validation of the parameters input to the inversion process is crucial to understanding the accuracy of the results.

Evaluating the efficiency of using different variants of background models for inversion calculations

2020 ◽  
pp. 36-52
Author(s):  
I. A. Kopysova ◽  
A. S. Shirokov ◽  
D. V. Grandov ◽  
S. A. Eremin ◽  
E. N. Zhilin
Keyword(s):  
Seismic Data ◽  
Oil And Gas ◽  
Rock Properties ◽  
Elastic Parameters ◽  
Reservoir Properties ◽  
Acoustic Inversion ◽  
Well Data ◽  
Background Models ◽  
Effective Penetration

The use of the method of seismic data acoustic inversion, in the presence of thick gas cap, can lead to difficulties when building background models of elastic parameters. In this regard, in the conditions of acoustically contrast thin environments within the perimeter of the Russkoye oil and gas condensate field, in addition to the standard version based on the well data, the authors considered a number of modified techniques ("block", "flat", and background models). The use of these background models provided the best results and made it possible to significantly improve the quality of predicting rock properties; based on the drilling results, effective penetration was ensured at 66 %, which was 102 % of the plan. Also, based on the inversion results, it became possible to predict reservoir properties using the Bayesian lithotype classification method.

3D Geological Model Creates Potential for Increased Production in Libyan Field

2021 ◽  
Vol 73 (08) ◽  
pp. 44-45
Author(s):  
Chris Carpenter
Keyword(s):  
Upper Cretaceous ◽  
Reservoir Characterization ◽  
Technical Conference ◽  
Reservoir Quality ◽  
Geostatistical Model ◽  
Reservoir Properties ◽  
Hydrocarbon Production ◽  
Reservoir Characteristics ◽  
Sirte Basin ◽  
Oil Company

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 201417, “Reservoir Characterization and Geostatistical Model of the Cretaceous and Cambrian-Ordovician Reservoir Intervals, Meghil Field, Sirte Basin, Libya,” by Mohamed Masoud, Sirte Oil Company; W. Scott Meddaugh, SPE, Midwestern State University; and Masud Eljaroshi Masud, Sirte Oil Company, prepared for the 2020 SPE Annual Technical Conference and Exhibition, originally scheduled to be held in Denver, Colorado, 5–7 October. The paper has not been peer reviewed. The study outlined in the complete paper focuses on developing models of the Upper Cretaceous Waha carbonate and Bahi sandstone reservoirs and the Cambrian-Ordovician Gargaf sandstone reservoir in the Meghil field, Sirte Basin, Libya. The objective of this study is to develop a representative geostatistically based 3D model that preserves geological elements and eliminates uncertainty of reservoir properties and volumetric estimates. This study demonstrates the potential for significant additional hydrocarbon production from the Meghil field and the effect of heterogeneity on well placement and spacing. Introduction The reservoir of interest consists of three stratigraphic layers of different ages: the Waha and Bahi Formations and the Gargaf Group intersecting the Meghil field. The Waha reservoir is a porous limestone that forms a single reservoir with underlying Upper Cretaceous Bahi sandstone and Cambro-Ordovician Gargaf Group quartzitic sandstone. The Waha provides excel-lent reservoir characteristics. The Bahi has fair to good reservoir characteristics, while the Gargaf Group has very poor reservoir quality. The Waha and Bahi contain significant amounts of hydrocarbons. The Bahi is composed of erratically distributed detritus from the eroded Gargaf Group. The characteristic of the Gargaf sediments is quartzitic sandstones indurate to a quartzite with low reservoir quality.

scholarly journals Enhancement of Region of Interest CT Reconstructions through Multimodal Data

2018 ◽  
Vol 4 (1) ◽  
pp. 331-335
Author(s):  
David Schote ◽  
Tim Pfeiffer ◽  
Georg Rose
Keyword(s):  
Substantial Reduction ◽  
Region Of Interest ◽  
Proof Of Concept ◽  
Multimodal Data ◽  
New Approach ◽  
Full Field ◽  
Lack Of Information ◽  
Ct Data ◽  
Flight Measurements

AbstractComputed tomography (CT) scans are frequently used intraoperatively, for example to control the positioning of implants during intervention. Often, to provide the required information, a full field of view is unnecessary. I nstead, the region-of-interest (ROI) imaging can be performed, allowing for substantial reduction in the applied X-ray dose. However, ROI imaging leads to data inconsistencies, caused by the truncation of the projections. This lack of information severely impairs the quality of the reconstructed images. This study presents a proof-of-concept for a new approach that combines the incomplete CT data with ultrasound data and time of flight measurements in order to restore some of the lacking information. The routine is evaluated in a simulation study using the original Shepp-Logan phantom in ROI cases with different degrees of truncation. Image quality is assessed by means of normalized root mean square error. The proposed method significantly reduces truncation artifacts in the reconstructions and achieves considerable radiation exposure reductions.

Unconformities on the Scotian Shelf

1974 ◽  
Vol 11 (1) ◽  
pp. 89-100 ◽  
Author(s):  
Lewis H. King ◽  
Brian MacLean ◽  
Gordon B. Fader
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Upper Cretaceous ◽  
Scotian Shelf ◽  
Early Tertiary ◽  
Late Tertiary ◽  
Glacial Processes ◽  
Well Data ◽  
Seismic Reflection Profiles ◽  
Cut And Fill

Four erosional unconformities have been recognized within the Mesozoic-Cenozoic succession on the Scotian Shelf, on the basis of data from high resolution seismic reflection profiles. Older unconformities are known from well data and others may be revealed by detailed biostratigraphic studies.The oldest of the four unconformities discussed in this paper is of Early Cretaceous age and appears to mark, with discordance, the boundary between Jurassic and Cretaceous strata on the western part of the shelf. A second angular unconformity, of Late Cretaceous age, has been recognized on the central part of the shelf where the basal part of the Banquereau Formation (Tertiary and uppermost Cretaceous) oversteps the zero-edge of the Wyandot Formation (Upper Cretaceous) and lies upon truncated beds of the Dawson Canyon Formation (Upper Cretaceous). Cut-and-fill relationships characterize a third unconformity developed during Early Tertiary time. A fourth unconformity was developed in Late Tertiary – Pleistocene time by fluvial processes and later by glacial processes. Although in many areas the latest unconformity appears to be the most conspicuous one on the shelf, its configuration closely follows the geomorphic expression developed during the previous period of erosion. The regional extent of the Cretaceous unconformities is not known, and they might only occur near basin margins and on structural and basement highs.

scholarly journals Seismostratigraphic Interpretation of Upper Cretaceous Reservoir from the Carpathian Foreland, Southern Poland

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7776
Author(s):  
Andrzej Urbaniec ◽  
Anna Łaba-Biel ◽  
Anna Kwietniak ◽  
Imoleayo Fashagba
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Tectonic Setting ◽  
Small Scale ◽  
Reservoir Properties ◽  
Southern Poland ◽  
Seismic Sequence Stratigraphy ◽  
First Results ◽  
Depositional Architecture ◽  
The Impact

The Upper Cretaceous complex in the central part of the Carpathian Foreland (southern Poland) is relatively poorly recognized and described. Its formations can be classified as unconventional reservoir due to poor reservoir properties as well as a low recovery factor. The main aim of the article is to expand knowledge with conclusions resulting from the analysis of the latest seismic data with the application of seismic sequence stratigraphy. Moreover, the seismic attributes analysis was utilized. The depositional architecture recognition based on both chronostratigraphic horizons and Wheeler diagram interpretations was of paramount importance. A further result was the possibility of using the chronostratigraphic image for tectonostratigraphic interpretation. Two distinguished tectonostratigraphic units corresponding to megasequences were recognized. A tectonic setting of the analyzed interval is associated with global processes noticed by other authors in other parts of the central European Late Cretaceous basin, but also locally accompanied by evidence of small-scale tectonics. This study fills the gap on the issue of paleogeography in the Late Cretaceous sedimentary basin of the Carpathian Foreland. It presents the first results of detailed reconstruction of the basin paleogeography and an attempt to determine the impact of both eustatic and tectonic factors on sedimentation processes.

Role of surface water in the formation of underground water in Aghstafachai-Ganjachai interfluve and its usage prospects

2020 ◽  
pp. 58-62
Author(s):  
A.R. Ibrahimova ◽  
Keyword(s):  
Underground Water ◽  
Point Of View ◽  
Tectonic Structure ◽  
Climate Type ◽  
Geophysical Surveys ◽  
Mineralization Degree ◽  
Well Data

With the purpose of water resources estimation of Aghstafachai-Ganjachai interfluve, geophysical surveys have been carried out. As a result, based on the well data, the maps were developed and interface conditions of the territory specified. The tectonic structure of Aghstafachai-Ganjachai interfluve lowland is associated with the formation of a sole artesian basin on its territory. Aghstafachai, Hasansu, Tovuzchai, Zeyemchai, Shamkirchai, Goshgarchai, Ganjachai and Kurekchai, being the main source of groundwater recharge, created a combined alluvial cone on the territory. The underground water of these rivers were studied in the sloping plain and the estimation of its volume carried out as well. It was revealed that the underground water on a large part of studied territory is fresh and less mineralized. From the bacteriological point of view, it is clean water. The content of microelements and harmful chemical substances in the water does not exceed the standards set for the drinkable water. Despite the long-term usage, the quality of the underground water, the mineralization degree and chemical composition remain unchanged. The regime of underground water is characterized with the irrigated climate type. Hydrogeological indexes and the parameters of ground water horizon in the studied area justify the possibility of their research for water supply.

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