Wellstrat Services Limited is an independent geological consultancy company, which through its personnel and associates offers a full range of analytical geological services.
Services offered include:
Wellstrat's personnel and associates provide biostratigraphical analyses; predominantly palynology, micropalaeontology and nannoplankton analysis. The application of biostratigraphy to hydrocarbon exploration, development and production is well understood, and Wellstrat's personnel offer a full range of high-resolution conventional and reservoir biostratigraphical analyses. Disciplines covered include:
These disciplines are used in the study of:
This is the study of acid resistant, organic-walled microfossils called palynomorphs. These are extremely useful environmental indicators as they can be derived from both marine and non-marine environments. Marine forms include acritarchs, chitinozoans, dinoflagellate cysts and prasinophycean algae. Pollen, spores and freshwater algae are the main non-marine groups.
The pollen and spores collectively known as sporomorphs together with dinoflagellate cysts are the main age indicators within the Mesozoic and Tertiary sequences. Acritarchs, chitinozoans and sporomorphs are the main groups used to date and characterise the Palaeozoic sections.
Quantitative analysis of samples is a primary feature of Wellstrat’s biostratigraphical approach. Using this approach reliable variations in the relative proportions of the different groups of marine and non-marine palynomorphs enables identification of subtle changes in palaeoenvironmental determinations. These changes together with similar variations identifiable through the other fossil disciplines can be incorporated into basic correlations and sequence stratigraphical models.
Analysis of the overall kerogen, including the palynomorphs referred to as palynofacies, provides an even greater resolution of the palaeoenvironmental interpretation.
Wellstrat's personnel have placed particular emphasis on developing our expertise in high-resolution palynofacies analysis in order to provide a powerful tool for horizontal biosteering in wellsite settings. Palynofacies is the study of the composition of acid resistant organic matter in sedimentary rocks, which can be used to aid the interpretation of depositional environments.
Palynofacies interpretation permits:
Micropalaeontology is the study of mainly marine, but some non-marine, microfaunal groups. Groups include foraminifera, ostracods, diatoms, radiolaria and miscellaneous micro- and macrofossils. The microfaunal groups are a critical part of palaeoenvironmental reconstructions. These are achieved by examining the presence or absence of benthonic and planktonic foraminifera, ratios of these foraminifera and the total diversity and composition of the microfaunas. Most of these forms are sensitive to water depth and some to temperature variations which provides environmental information on water salinity and depth.
Nannofossils are the microscopic calcareous remains of marine unicellular phytoplankton. Nannoplankton range in age from Late Triassic to Recent and are particularly useful in stratigraphical resolution of Cretaceous to Tertiary calcareous sequences.
Conodont analysis is particularly useful in subdivision of calcareous Carboniferous sequences. This service is offered through our associated company Conodata International.
Suitably qualified specialists are available for detailed age or palaeoenvironmental reconstructions of all other micro- and macrofossil groups.
Hot-shot analysis is available for palynology/palynofacies, micropalaeontology and nannofossils from both Flintshire and Aberdeen. We aim to achieve results within 3 – 6 hours from receipt of samples in the laboratory.
Wellstrat’s personnel and associate’s world-wide experience includes Northwest Europe, Africa, Middle and Far East, Caspian Sea and North and South America, offering complete stratigraphical coverage for the whole geological column.
Our extensive experience in North Africa and the Middle East has been gained through detailed high-resolution single and multi-well biostratigraphical studies including:
Wellstrat's personnel and associates continue to be very active in Libya. We have developed unrivalled experience in the biostratigraphy of Cretaceous and Tertiary sequences of the region. Current projects include:
Wellstrat are particularly active in Sudan. This is a frontier area for palynology, and our expertise has been fully developed in-house. Projects have included a multiwell correlation study of the Muglad Basin in Southwest Sudan. Sequences from Neocomian to Quaternary have been studied for palynology and palynofacies. A full understanding of the stratigraphical distribution of palynomorphs from this palynofloral province has been achieved. Projects Wellstrat's personnel have completed include:
Based on this wealth of experience Wellstrat is able to provide the most up to date analyses and interpretations for any well or outcrop section. Through our network of associates other geological disciplines can be integrated to provide a complete solution to any exploration questions. In summary we offer:
Sedimentological and Petrographical Analyses
A range of services aimed at characterisation of depositional environment, geometry, and factors controlling clastic and carbonate reservoir quality and its variability are offered through our associated company Integrated Reservoir Solutions (IReS). Services include:
Heavy mineral analysis is an alternative method of correlation that utilises stratigraphical changes in mineralogy mainly in clastic sediments. This method can be used to complement biostratigraphic analysis, or as a stand-alone method in barren sequences. It also provides information on sediment provenance, transport history and diagenesis. The technique combines transmitted light microscopic analysis with single-grain electron microprobe analysis to maximise stratigraphical resolution. This analysis is offered through our associates HM Associates.
A full range of analytical, interpretative and training services in petroleum geochemistry are available through our associates GHGeochem Limited. Geochemical programmes can be devised for client’s projects, training in all aspects of geochemistry, data review work, reservoir geochemistry studies, maturation modelling and all aspects of geochemical interpretation.
The main services can be summarised as follows:
Wellstrat's personnel can assess the level of carbonisation of a sample by studying the colour of the palynomorphs within an assemblage. The results are compared to a Thermal Alteration Index (TAI). This is a numerical scale based on palynomorph colours and linked with phases of organic maturation and petroleum generation. As the palynomorphs undergo thermal maturation the colour deepens from yellow through brown and finally black. By recording these colour changes and comparing them to the Thermal Alteration Index, an initial assessment of the geothermal history, and therefore petroleum potential, can be established.
Basin modelling is a service available through experienced specialists on 1-D, 2-D and 3-D modelling packages dependent on client's requirements. Particular emphasis is placed on thermal history modelling which is the key for accurate prediction of timing and volumes of hydrocarbon generation. The results can show the timing and amounts of generation as well as the direction of migration.
Sequence stratigraphy is the study of biostratigraphy, chronostratigraphy, sedimentology and seismic stratigraphy with the aim of producing a framework for the correlation of sedimentary facies. This framework is used in facies mapping, the development of reliable sequence stratigraphical models, developing a better understanding of sediment distribution within a reservoir sequence and predictive geological modelling.
Relevant sequence stratigraphical studies involving Wellstrat's personnel and associates include:
This is a new tool for sequence correlation, complementing conventional biostratigraphy and offering improved resolution over conventional chemical stratigraphy in thick and monotonous, barren and fossiliferous sections. It enables the recognition of stratigraphically significant events and surfaces, and provenance changes by chemical element fingerprinting. This technique can be combined with biostratigraphy in fossiliferous sections to test and refine biostratigraphic interpretations and correlations. Furthermore it is independent of fauna and flora, and thus can be used to extrapolate sequence stratigraphic models into continental and other poorly fossiliferous sediments.
The description and graphical representation of the lithology of sediments plays a crucial part in the understanding of any sequence. A similarity in lithologies is a conventional method of correlation between well sections. As similar lithologies occur in different age sediments stand alone interpretations have to be treated with caution. However when lithological interpretations are combined with biostratigraphical data they provide a more robust tool in correlation.
Wireline Log Analysis and Correlations
This technique is used to define the wireline log characteristics of sedimentary packages and their bounding surfaces. Wireline profiles of similar character, preferably constrained by biostratigraphical or chemical events, can be correlated as a basic geological tool.
Wellstrat's personnel have developed their expertise in high-resolution biostratigraphical analysis in order to provide a powerful tool for interpretation of depositional environments. Biofacies (microfauna, microflora and palynofacies) analysis represents a geological interpretation of sedimentary dispersed organic material, which together with lithofacies studies can provide the key to identification of depositional environments. Different lithofacies have their own physical characteristics related to grain size and sorting variations, which are largely dependant upon depositional processes, such as supply of sediment and depositional energy conditions. Similar depositional processes, however, may not always be limited to one environment and can be found in quite contrasting types of depositional settings. Thus, from lithofacies alone, it is not always possible to reconstruct precisely the palaeodepositional environment. In this respect, a biofacies approach in conjunction with sedimentology can permit a more accurate environmental intrepretation and the ability to reconstruct palaeodepositional settings.
The provision of specialised personnel in wellsite settings, both onshore and offshore, is a core service offered by Wellstrat.
Biostratigraphy is the main discipline utilised at the wellsite to give stratigraphical control through drilled sections. This facilitates accurate casing, coring point and TD selection. Wellstrat's personnel have helped develop a method of biosteering using palynofacies in sand dominated reservoirs. A mobile palynological processing unit and technical support staff are available through associates for wellsite contracts. The advantages of wellsite biostratigraphy can be summarised as follows:
A revolutionary new chemical analyser has been specially developed for wellsite operations through our associates. This new equipment provides real-time analysing of the cuttings while drilling. The results enable the recognition of stratigraphically significant events and surfaces, and provenance changes by chemical element fingerprinting. This technique can be combined with biostratigraphy in fossiliferous sections to refine the stratigraphical control. It can also be utilised in poorly fossiliferous sediments.
Transmitted light microscopic analysis for heavy mineral interpretation is available through our associates. This analysis has been used on a number of occasions in conjunction with biostratigraphy, increasing the stratigraphical control of the well bore in real-time. In other areas where biostratigraphic control is limited then Heavy Mineral analysis has been used as an independent technique.
The description and graphical representation of the lithology of the drilled section is available at the wellsite.
Petrographical and microfossil analyses by transmitted light microscopical examination is another service that is offered at wellsite through Wellstrat.
Other services provided include the following:
Project and Data Management
Wellstrat has gained vast experience in conducting multi-well and multi-disciplinary studies in several geological basins worldwide, most recently in North Africa, especially in Libya. These long-term studies also involved data and sample material management. We are now able to offer project and data material management services at the client’s offices as well as in our offices and store-facilities in the United Kingdom.
Wellstrat Services, through their membership of various professional societies, have access to some of the finest map and literature reference libraries in the world. These facilities can be accessed for review and copies of selected articles, subject to copyright rules, can be arranged to our client’s requirements.
Training and Courses
Wellstrat can arrange full training in all aspects of the following Geological Analytical Services.
This training is lecture, laboratory and / or field based and is specially designed to fit individual client requirements.
Our training and short courses have the advantage of supplementing lectures with case histories, extracted from our in-house research data and related commercial projects.
Field courses have proven benefits and are offered at a variety of levels and locations, from specific focused topics to a more general introductory level suitable for support staff.
1. Short course on the industrial application of palynological sciences with particular emphasis on the North African and Middle Eastern petroleum provinces.
The course available is primarily aimed at oil industry personnel working in North Africa or the Middle East who require a working knowledge of the application of palynology to hydrocarbon exploration. Various modules can be made available, including Palaeozoic palynology and Late Cretaceous to Tertiary palynology. This short course can be tailor-made to the client’s requirements, and other modules can be made available as required. The course is also open to biostratigraphers who require retraining in palynology; or an expert introduction to the North African and / or Middle Eastern regions; or managers and supervisors who need to interact with biostratigraphers. Non-industrial personnel are also welcome to attend this course.
2. Workshop course on sedimentary organic matter composition and maturation analysis for evaluation of the source rock potential and petroleum generation.
The course is primarily aimed at oil industry employees who wish to train in kerogen analysis, palynomorph (miospore) colour and maturation studies under transmitted and fluorescence light microscopy. The training will involve examination of various kerogen types such as vitrinite, inertinite (woody material) and sapropelic organic matter (SOM) for the interpretation of palynofacies and palaeoenvironments. The degree of thermal maturation and metamorphism of organic matter permits identification of the source quality, maturity and hydrocarbon generation potential of the source sediments. The data generated from these studies when integrated with the analytical geochemical studies provides a better understanding of the geochemical history of a petroleum basin.
Recent training courses run by Wellstrat Services include the following:
Wellstrat is actively engaged in identifying non-proprietary geological projects and is currently engaged in the following project:
1 Regional Geology of the Orange Basin, Offshore Republic of South Africa.
This project is conducted jointly with IReS and the Petroleum Agency of South Africa.
Wellstrat can offer full processing services for all biostratigraphical disciplines. These include standard palynological preparations for palynostratigraphy and palynofacies, washed and picked (quantitative and semi-quantitative) micropalaeontological preparations, thin sections suitable for micropalaeontological and petrographical analyses and nannofossil preparations. A mobile palynological processing unit and technical support staff are available for wellsite contracts.