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Abstract Prestack anisotropic (orthotropic symmetry) AVAz inversion of full-azimuth 3D seismic data for fracture characterization of the upper Najmah Formation in northern Kuwait was conducted. This formation comprises a thin, tight, naturally fractured carbonate overlying a kerogen-rich shale source rock. The inversion methodology uses an orthotropic system of symmetry that is appropriate for analysis of vertical transverse isotropic (VTI) anisotropic rock layers containing swarms of aligned vertical fractures. Measured seismic amplitudes show good agreement with synthetic models created at different well locations, indicating reliable representation of fractures in amplitude data. Inversion results show good agreement with well and drilling data. Rock-physics modeling shows a relationship between elastic properties and seismic anisotropy and between elastic properties and reservoir properties, such as porosity and fracture density.
- Research Report > New Finding (0.49)
- Research Report > Experimental Study (0.35)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.53)
- Geophysics > Seismic Surveying > Seismic Processing (1.00)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.88)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling > Seismic Anisotropy (0.49)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > SAMA Formation (0.99)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale gas (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- (2 more...)
Subsurface and Wells Technical Data Architecture and Flow
Nazir, Nancy (Shell) | Dashti, Qasem (KOC) | Al Ashwak, Samar (KOC) | Al Ajmi, Neema (KOC)
Abstract Objectives/Scope This architecture is a result of a study completed for the Kuwait Oil Company under the Enhanced Technical Services Agreement with Shell. Specifically this covered subsurface data management. Several visits to Kuwait were required and during interviews with key stakeholders gaps where identified and many issues highlighted. The recommended architecture was modified to incorporate these requirements and finally agreed and approved. Methods, Procedures, Process This architecture was centered on having a QCed data store with seamless integration to KOC current existing systems. This reduced cost by the elimination of the need to introduce a new database. Further, this structure built on the existing knowledge base in place was a key factor in the architecture approval. The existing fragmented systems were characterized by different data values and data in several locations. There was a clear need for an integrated QCed data store. The need for clear accountabilities and for different disciplines to work together more closely was very much evident. The concept is derived from our Shell architecture structure concept but utilizing KOC existing systems. The focus in this architecture is on the seamless integration and defining clear data flows and roles and accountabilities. Each data type is covered by flow charts to specify the flow of data and the assigned focal points responsibilities and how the data is managed throughout the process. The structure and process is intended to keep the master data store always current with the latest QCed data. Uploading and quality review of the initial data set is therefore a key first step. Results, Observations, Conclusions With clear accountabilities and responsibilities defined and a clear data workflow the data store will be always in good shape. Having the QCed assured data at your fingertips saves a lot of time and money. Novel/Additive Information Having the technical user in ownership of his data and resposible on it's evergreening will assure the rest of the technical community they are using the latest most QCed data.
Abstract The Kuwait Oil Company is developing the North Kuwait Jurassic Gas fields in order to increase domestic gas supply. The reservoirs are difficult with deep, poor quality reservoirs under high pressure containing H2S and CO2 leading to significant challenges. KOC entered into an Enhanced Technical Service Agreement (ETSA) with Shell in order to benefit from IOC expertise and to optimize the development. Some 40 Shell staff work with KOC. A core element of the ETSA is to build and enhance KOC's staff competencies to develop the North Kuwait Jurassic Gas fields. This professional competencies development program is done through the application of various training and coaching activities. KOC has an established and well-structured competence assessment and training regime for all staff under their employment. Shell, with its wide experience in sour and High Pressure/High Temperature (HPHT) gas field development, is well placed to complement and build on this important competency development process. Shell has embarked on a journey to shorten it's time-to-autonomy by transitioning from traditional classroom training to providing structured development programs including on-the-job-training, blended learning and coaching. The paper will describe how training and coaching activities were selected for KOC's North Kuwait Jurassic Gas team, how they were implemented and monitored, and what the critical success factors were. Shell's training and coaching program to the North Kuwait Jurassic Gas team have started five years ago with a steady increase of activities year-on-year. The multiple years' implementation of the North Kuwait Jurassic Gas competency development program have allowed for learnings, review and fine-tuning of the program. The paper will address the most important elements for a successful training and coaching program in this unique partnership. This contains of four elements, the role of management and business; type of training and coaching event; staff's own involvement and training program management. The paper will show how an IOC supports an NOC to enhance staff competencies in a challenging technical area, how this training and coaching plan is being managed and executed and what are key elements to consider.
GeoSteering Through Challenging Fractured Limestone Reservoir becomes Achievable Utilizing High Definition Multi-Layer Boundary Mapping Technology - A Case Study from a Deep Gas Reservoirs
Al-Ajmi, Saad A. (Kuwait Oil Company) | Pattnaik, Chinmaya (Kuwait Oil Company) | Al-Dawood, Ahmed E. (Kuwait Oil Company) | Dashti, Qasem (Kuwait Oil Company) | AlFailakawi, Abdul Aziz (Kuwait Oil Company) | Chakravorty, Sandeep (Schlumberger Oilfield Eastern Limited) | Chandan, J. Keot (Schlumberger Oilfield Eastern Limited) | El-Derini, Khaled M. (Schlumberger Oilfield Eastern Limited)
Abstract Kuwait Oil Company is currently engaged in an early phase development of deep sub-salt tight naturally fractured carbonate reservoirs. These reservoirs has been tested and found to be gas bearing. They are uniquely characterized by dual porosity nature where natural fracture network systems are the primary flowing mechanism. The foremost challenge to produce from these reservoirs is the wellbore interaction with the natural fracture network systems. Despite drilling around 85 vertical and slightly deviated wells in this large challenging HP/HT reservoir complex, understanding and characterization of fractures is a challenge in the absence of horizontal wells, though fracture understanding has improved over time through careful integration and interpretation of logs, core, and seismic data. To achieve the dual objective of characterizing the fractures and to boost production, asset team recently embarked on the strategy to drill horizontal wells targeting these challenging tight reservoirs. As a fit for purpose solution to address these challenges, "High Definition Deep Directional Multi Boundary Detecting Technology" was incorporated in the drilling plan so that horizontal producers could be geosteered in the desired target intersecting as much fractures as possible. This technology, an advancement on the 1st generation "Distance to Boundary" technology is characterized by its extended capability to detect multiple bed boundaries based on resistivity contrast up to 20ft around the wellbore. The significantly improved new multilayer stochastic inversion also solves for structural dip along the wellbore azimuth (longitudinal dip). In the lateral section, this technology successfully mapped the reservoir roof as well as multiple thin intra layers inside the target reservoir along with information on longitudinal dips which helped immensely to optimize trajectory inclination and spatially position the wellbore across different layers as per plan. Apart from detecting reservoir boundaries, the inversion also mapped conductive and resistive fractures cutting wellbore at high angle for the first time, while trajectory was drilling across a fracture corridor. This further added confidence to geo-steering while drilling as wellbore cutting through such a fracture corridor was highly anticipated in predrill planning. Drillpipe conveyed borehole images acquired after drilling the well confirmed the presence of large swarms of fractures detected through inversion. The effective integration of data from different fields in a single platform, like LWD logs, boundary information, dip information, drill cuttings information and decisions taken based on the interpreted information paved the way for the successful drilling of this well and achieve the predrill objectives.
- Geology > Geological Subdiscipline > Stratigraphy (1.00)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.43)
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (0.68)
Field Development and Well Planning in Tight Carbonate Reservoir Using Fracture Characterization and In-Situ Stress Mapping From Core Reorientation Studies: Kuwait Case Study
Pattnaik, Chinmaya (FDGS, Kuwait Oil Company) | Rao, Narhari Srinivasa (FDGS, Kuwait Oil Company) | Al-Ashwak, Samar (FDGS, Kuwait Oil Company) | Al-Ajmi, Neema Hussain (FDGS, Kuwait Oil Company) | Kidambi, Vijaya Kumar (FDGS, Kuwait Oil Company) | Al Anzi, Abdullah Motar (FDGS, Kuwait Oil Company) | Dashti, Qasem (FDGS, Kuwait Oil Company) | Staffelbach, C.. (Corias) | Barbé, Jean-françois (Corias)
Abstract Fracture characterization is vital for efficient field development of naturally fractured Carbonate reservoirs. Successful development of fracture reservoir in the study area was possible due to early recognition of fracture play right from the exploration phase and through careful execution of relevant data acquisition campaign in the initial stages of field development. Comprehensive and integrated studies have been carried out over the past few years to arrive at an understanding of the conceptual model in deciphering structural evolution of North Kuwait Jurassic. Extensive core and image log data was acquired in the initial stages of field appraisal, which helped in comprehensive forward planning in design of deviated and horizontal wells. The data analysis steps included accurate and reliable reorientation of the cores. These data were calibrated with the image logs, along with available seismic attributes, which resulted in better understanding of structural evolution and sweet spotting of horizontal wells. This reorientation of the core data also helped in establishing a number of quantitative fractures attributes such as frequency, spacing, dip-azimuth and aperture along with mapping of in-situ stress directions. The detailed integration of these data also helped in accurately mapping the local and regional present day stress and its variations spatially across the fields. Stress direction across the field was helpful for deciding the azimuth of wells during well planning along with selection of completion strategy for current set of horizontal drilling Campaign. Drilling and testing results have been encouraging through enhanced reservoir performance in these tight carbonate reservoirs, based on these integrated studies.
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Carbonate reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Faults and fracture characterization (1.00)
Coexistence of Gas-Condensate and Volatile Oil at Pressure Higher than Saturation Pressure. Physical Explanation and Modeling Approaches. Case Study: Sabriyah Field in North Kuwait Jurassic Asset
Fava, Guido (Schlumberger) | Descubes, Elena (Schlumberger) | Daoud, Ahmed (Schlumberger) | Sharifzadeh-Najafi, Ahmad (Schlumberger) | Al-Enezi, Bashayer (Kuwait Oil Company) | Al-Arouj, Mutlaq (Kuwait Oil Company) | Dashti, Qasem (Kuwait Oil Company)
Abstract Sabriyah and Raudhatain are the main fields producing from the Middle Marrat Jurassic formation in North Kuwait with approximately 5 km distance between the two fields. Raudhatain fluid is considered as Volatile Oil, while Sabriyah is described as Gas-condensate. 16 PVT samples from Raudhatain were analyzed and described as Volatile oil. 12 PVT samples taken from Sabriyah field where 7 samples show gas condensate behavior and rest shows volatile oil. A key challenge in understanding the Sabriyah fluid characterization is the fact that 5 well samples that showed Volatile oil behavior are not separated from the Gas condensate wells by any apparent barrier. In addition, the initial reservoir pressure is much higher than the saturation pressure, preventing the equilibrium of those fluids. The objectives for this study are to analyze the physical explanation of coexistent of oil and gas-Condensate in one communicated reservoir with reservoir pressure higher than saturation pressure, apply different modeling approaches to accurately describe the fluid behavior in Sabriyah field and finally capture the influence of uncertainty in the type of fluid on the production forecast. The physical explanation for this phenomenon was investigated from different points of view: the variation of temperature, compositional variation with depth, existence of geological barriers, and facies changes. It was found that the compositional variation with depth and the change of fluids with changes of facies can provide reasonable explanation for this phenomenon. The first explanation related to compositional variations with depth is supported by the observed data that shows a strong relationship between depth and fluid type, while the temperature did not influence significantly the gas-oil phase change. The second explanation related to the concept of gas and oil charge depending on facies is supported by mercury injection capillary pressure data taken from different depth in the reservoirs, this concept improves the understanding of fluid distribution which could not be explained in previous approaches. This paper shows the way of modeling this phenomena based on these two explanations, which honor both static and dynamic data with special reference to the effect of these different modeling approaches on the production forecast of Sabriyah field. The near critical fluids which are the type of fluids in Sabriyah field are usually problematic to handle with Equation of State; therefore solving this particular case is expected to add technical value to reservoirs of the same type of fluids. The facies dependence of gas and oil distribution and the way of modeling this phenomenon is an innovative view that can contribute to the description of similar fields.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Upper Marrat Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sargelu Formation (0.99)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Sabriyah Field > Marrat Formation > Sabiriyah Mauddud (SAMA) Formation (0.99)
- (3 more...)
Integrated Reservoir Characterization of Deep Kerogen-rich Unconventional Resource Play in North Kuwait
Rao, Jonna Dayakar ((Kuwait Oil Company)) | Al-Ashwak, Samar ((Kuwait Oil Company)) | Al-Anzi, Abdullah Motar ((Kuwait Oil Company)) | Maki, Musaed Yaseen ((Kuwait Oil Company)) | Narhari, Srinivasa Rao ((Kuwait Oil Company)) | Dashti, Qasem ((Kuwait Oil Company)) | Chakravorty, Sandeep ((Schlumberger))
Abstract Organic-rich Kerogen of Lower Kimmeridgian to Upper Oxfordian age comprises of thinly laminated Kerogen with calcareous mudstone deposited in deep basinal environment. It has a consistent thickness of 50' in the entire study area with an average porosity of 4-6pu with nanodarcy permeability and is the main source for hydrocarbon plays in Kuwait. This rock sequence occurs at depths of 14000-15000 ft under HPHT conditions. Huge success of shale gas plays in North America has prompted the characterization of these source rocks to evaluate their resource play potential for the first time in Kuwait. The Kerogen under study differs from proven US Shale gas fields in terms of comparatively higher TOC content, greater depth and much less in thickness (50ft) and in a Pre-salt setting. Hence these are challenging in terms of completion and production. These are inferred to be Type II Oil & Gas prone based on Vitrinite reflectance range from 0.98 to 1.17. Tight rock analysis (TRA) and geo-mechanical studies of selected core samples within the study area provide critical input for Kerogen characterization. Kerogen is divisible into seven units based on electro-logs and log derived TOC and are correlatable with distinct facies assemblage, TRA derived petrophysical data and Geomechanical properties. Core derived UCS, Triaxial Compression test and Brazilian test based on lab results have brought out clear anisotropic behavior and enabled to bring out mechanical stratigraphy by integrating geomechanical properties and litho-facies variations within the Kerogen. This workflow has brought out the distinction of the carrier beds in alternations with Kerogen-rich layers as well as planned well trajectory along the carrier bed in the central part of Kerogen. Lastly, proppant compatibility tests combined with Young's Modulus provide valuable input for planning horizontal wells and subsequent hydro-frac design for completion.
- North America > United States (0.94)
- Asia > Middle East > Kuwait (0.93)
- Phanerozoic > Mesozoic > Jurassic > Upper Jurassic > Kimmeridgian (0.55)
- Phanerozoic > Mesozoic > Jurassic > Upper Jurassic > Oxfordian (0.54)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- Geology > Rock Type > Sedimentary Rock > Organic-Rich Rock (0.71)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.57)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (0.94)
Challenges and Uncertainties in Reservoir Geomechanical Characterization for Horizontal Well Planning in Deep Unconventional Reservoirs in North Kuwait Fields
Acharya, Mihira N. (Kuwait Oil Company, Kuwait) | Chakravorty, Sandeep (Schlumberger, Kuwait) | Al-Mershed, Abdul Mohsen (Kuwait Oil Company, Kuwait) | Darous, Christophe (Schlumberger, Kuwait) | Joshi, Girija K. (Kuwait Oil Company, Kuwait) | Al-Ajmi, Mejbel S. (Kuwait Oil Company, Kuwait) | Dashti, Qasem (Kuwait Oil Company, Kuwait)
Abstract Appraisal of deep unconventional reservoirs through horizontal and high angle drilling campaign in North Kuwait Jurassic Fields requires the knowledge of in-situ stress regime, particularly orientation and magnitudes, to provide optimized solution for safe drilling and completion designs. A comprehensive geomechanical analysis i.e. broader geomechanical framework of the overburden section and a detailed geomechanical characterization at the reservoir targets for drainhole section, for the best possible orientations and stability parameters during drilling and completion is a key for the fields with sparse vertical and deviated wells control and short production history. This paper outlines the integrated approach adopted and discusses the challenges and uncertainties in the reservoir geomechanical modelling and characterization. Interpretation of caliper data and borehole images are used to determine the stress direction for vertical and near vertical wells. The minimum stress and maximum stress directions are established from orientation of breakouts, maximum ovality from calipers and from orientation of drilling induced fractures respectively. Comprehensive integrated geomechanical properties for all the formations units of the unconventional reservoir sequence are computed. The results indicate that the stress regime varies from ‘strike-slip to inverse’ and are found being formation dependent with associated intrinsic rock mechanical properties and spatial position of the wells under study. 1-D mechanical earth model (MEM) and WBS analysis are also done to calibrate the results. The stress magnitudes are constrained using data frac job results. Results of study and knowledge of stress direction and regime are used for the planning and defining horizontal well trajectories optimization as well as in estimating mud weight window for safe drilling and optimizing completion designs.
- Geophysics > Borehole Geophysics (1.00)
- Geophysics > Seismic Surveying > Borehole Seismic Surveying (0.90)
Abstract North Kuwait Jurassic Complex consists of 6 fields with 4 major reservoirs. Total of 19 integrated reservoir models incorporating seismic, geological, petrophysical, and engineering data have been constructed to delineate the reservoirs and perform multi-scenario production forecast for the whole field. These models are dual porosity, with near critical fluids of gas condensate and volatile oil. There are different challenges to model the whole fields that can be summarized as follows. First, the two main producing reservoirs among all fields are (RA) and (SA) which account for about 40% of the hydrocarbon in place. These two fields show existence of different free water levels (FWL) along the areal extension of both fields without any evidence of compartmentalization based on pressure data. Second, all the asset is producing towards one common facility where some fields are gas condensate and some other is volatile oil. Third, modeling the fields using compositional simulator with dual porosity system will complicate the models and increase the running time. This paper explains the approach adopted to solve most of these challenges. First, a numerical approach was implemented to allow communication between these blocks of different FWL's at the hydrocarbon zone only. Thus, ensure the equilibration of the system with honoring the geological understanding and allowing pressure communication through the hydrocarbon leg. Second, a proposed approach of using the standalone simulation models for running different sensitivities to select the optimum development plan per each field and then couple them with one controller at the surface to get the optimum field development plan for the whole fields as one asset producing through one common surface facility. Third a black oil delumping approach was used to convert the black oil to 35 pseudo components based on different EOS models generated per each field. Thus getting the advantage of speeding up the run based on using black oil simulation and reporting the change in composition with time using a simple black oil delumping look up table.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)
Modeling from Reservoir to Export: A Compositional Approach for Integrated Asset Model of Different Gas Fields in North Kuwait Jurassic Carbonate Reservoirs
Torrens, Richard (Schlumberger) | Daoud, Ahmed (Schlumberger) | Amari, Mustafa (Schlumberger) | Sharifzadeh, Ahmad (Schlumberger) | Prakash, Roshan (Schlumberger) | Al-Enzi, Bashayer (Kuwait Oil Company) | Dashti, Qasem (Kuwait Oil Company)
Abstract A project was undertaken to construct an overview to build an integrated asset model (IAM) of an onshore fractured carbonate gas condensate and volatile oil asset in Northern Kuwait that is considered the first gas asset discovered in Kuwait. The asset has the potential to produce from six distributed fields producing from four hydrocarbon-bearing structures. The development strategy calls for extensive drilling and facilities expansion to increase and sustain production with the potential addition of depletion compression to further sustain the plateau. Because the reservoirs are highly compartmentalized, they are split into 19 separate models. Production is through three surface facilities, fluids vary significantly across the field from sour gas condensate to volatile oil, and it is important to consider the impact of reservoir deliverability, facilities capacity, and surface backpressure when evaluating different development scenarios. A novel IAM was constructed that integrates reservoirs, wells, pipelines, and facilities models into an integration platform. The IAM comprises 19 black oil dual porosity reservoir models coupled to a compositional network model via black oil delumping to convert the subsurface rates into six-components composition. A split table (compositional delumping) is then used to convert the six-components composition to 35 surface components to be used in the equation-of-state (EOS) surface network models to estimate the composition at each point at the surface (inlet and outlet of each facility). Then the network model is coupled to surface facilities modeling to estimate the rates and composition at the export level. This idea of mapping the subsurface fluid from black oil at subsurface to compositional at surface reduces the subsurface running time and makes the IAM more feasible from the running time perspective. The IAM has highlighted several differences versus the stand-alone modeling and the coupled modeling at the surface only. First, more accurate accounting for backpressure results in an increase in the plateau. Second, a production forecast for each facility gives a detailed analysis of production and the number of wells for each facility. Finally, detailed compositional information becomes available at all points in the surface network, which is important input to the facilities design.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Upper Marrat Formation (0.98)
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > North Kuwait Jurassic (NKJ) Fields > Marrat Formation > Sargelu Formation (0.98)