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Petroleum Geoscience Conference & Exhibition 2013
- Conference date: 18 Mar 2013 - 19 Mar 2013
- Location: Kuala Lumpur, Malaysia
- Published: 18 March 2013
61 - 80 of 103 results
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A Robust Static Modelling Approach to Support EOR Field Development Plan (FDP), Offshore Sabah, Malaysia
Authors H.P. Lee, K.F. Boey, K. Paranthaman, C.W. Hong and T.K. NyanatThis paper discusses a robust subsurface modelling approach and the quantifications of key uncertainties associated with turbidite sandstones to support water flood and EOR Field development project in an oil field offshore Sabah, Malaysia. The paper demonstrates integration of multi-disciplinary data, geological concepts and field production performance data in building static and dynamic simulation models to support Field Development Planning. Some new aspects of the field understanding are presented based on new data acquired during the two phases of development. These are: a)New geological and petrophysical interpretations based on new wells calibraeted to reprocessed seismic data. b)Building of multi-scenarios deterministic models (Low, Base and High case)
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Fractures Identification While Drilling
Authors M. Bazara, A. Basyouni, M. Al-Sharafi, Z. Al-Kindi and Z. GhafriDrilling a highly deviated wells in a heavily fractured and complex heterogeneous Carbonate formations is a challenging process that requires a real time monitoring and utilizing an MWD and LWD technology. -Currently PDO is developing X field and drilling horizontal wells for Gas in A formation in which the reservoir compromises a heterogeneous vuggy limestone and a fractures network that is distributed all over the field. The challenge faced during drilling is the total drilling mud losses due to presence of major fractures consequently those fractures represent a threat for early water break through and shortening the life of the well. PDO has utilized the Ultra high resolution LWD resistivity images in several wells to tackle this problem, which successfully helped to identify the fractures zones that contributed to the drilling mud losses and design completion to isolate those fractures zones. As well as selecting a proper perforation zones away from the fractures. The Geological interpretation of the high resolution resistivity images revealed the presence of a few major conductive fractures that were possibly enhanced by drilling and a large number of partial discontinuous conductive and resistive fractures.
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Have We Done Enough Research in Gas Flood IOR/EOR Technology
By A. HageFurther experimental work and research is mandatory for successful IOR/EOR piloting. Further investigation is required to ensure full understanding of phase behavior at different conditions and ensuring flow assurance under secondary and tertiary depletions. The techniques used to determine MMP and MME are not optimum. Depressurizing experiments showed contradictory results against titration experiments for AOP/AOC against CO2 and N2. Core-flood experiments and proper up-scaling procedures are also questionable, taking into consideration flow-assurance challenges of solid precipitation and deposition causing potential formation damage, which necessitates further investigation for each phase of the workflow process
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Using Integrated Modelling Approach to Evaluate the Use of IWAG EOR Process
Authors S. Vijapurapu, A. Ghosh, S.F. Kho, K.H. Leong, G.J. Reijnders and G. StoneField A situated, offshore Borneo, Malaysia, with 30 years of production, was identified as candidate for Enhanced Oil Recovery (EOR). Immiscible water alternating gas (iWAG) was identified as a suitable EOR process from screening studies. Implementation of Enhanced Oil Recovery schemes for brown field re-development requires an understanding of recovery mechanisms from pore-scale to the field scale, and commonly requires the use of reservoir models which can represent the reservoir at these different scales. A fit-for-purpose integrated reservoir modeling (IRM) approach to analyse the risks and benefits of IWAG process will be presented in this paper. Results of the study would help in understanding the IWAG process and in the implementation of the EOR scheme in the other fields in the region, which have similar geological setup and depositional environments.
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Thin-Bed Geology and Borehole Image Logs - Back To Nature
More LessIf we work with the models for too long, we risk forgetting what nature really looks like and our preferred models and methods may take over with a considerably less-than-optimal effect. Occasionally, we need to re-calibrate our perceptions with a dose of reality. In reality, thin beds are found in almost all sedimentary environments and are the results of processes that involve pulsed sedimentation from varied flow regimes. Thin beds may represent instantaneous events (minutes) or deposit over hundreds of years. Thin beds are characterised by a range of structures, textures, and composition that includes not only thickness but bed-boundary sharpness, grain size changes, sorting, bioturbation, mineralogical variations (detrital and cementation). All these factors contribute to the complexity that our models necessarily attempt to simplify. A better understanding of the depositional and post-depositional processes that result in thin beds gives us a deeper appreciation of why thin beds are difficult to evaluate. A deeper appreciation should result in better estimates of P10, P50, P90 values and translate into improved uncertainty limits. In the absence of core, only borehole image logs provide us the data from which we can conceptualise and interpret depositional processes and allow us to reduce uncertainty.
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Predicting Net Sand at Kebabangan Field for 2013 Drilling Campaign, DW Sabah, Malaysia
Authors A. Bolhassan and C. M. CurtisEstimation of net-to-gross in a complex amalgamation of varying reservoir bed thickness presents many challenges. Deploying conventional shale volume cut-offs to determine net sand distributions in these types of reservoirs, as seen in the Kebabangan Field, can be misleading because conventional logs can by-pass potential hydrocarbon bearing intervals due to the so-called “low resistivity and low contrast” response that can occur in thinly laminated beds. Using the thin bed analysis (TBA) with Thomas-Stieber approach to quantify net sand within both thick beds and thinly laminated beds was found to be an effective and repeatable method in evaluating net sand distributions in a well; mainly because it utilizes only basic log data as inputs; and therefore, can be applied in all the planned Phase I development wells and reservoir intervals. By integrating and comparing the net sand results with the sand count from core and log images, we can demonstrate the successful applications of Thomas-Stieber approach in quantifying net sand in both thick blocky sands, as well as, thinly laminated reservoirs sands in Kebabangan field.
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Application of Matching Pursuit to Spectral Decomposition, Issues and Solutions
Authors D.C. Adams and D. MarkusApplications of Matching Pursuit signal analysis methods have made significant inroads into use in seismic data analysis. In our review of the geophysical literature we found applications to migration, interpolation, spectral decomposition and others. Our review also indicated three areas where thorough understanding of practice, as it applies to spectral decomposition, is lacking and leads one to ask the following questions: (1) given that Morlet wavelets are commonly used in the analysis, do dictionaries based on them adequately predict synthetic and extracted seismic wavelets? (2) Can the properties of a seismic trace be used to limit the dictionary to a reasonable size? (3) How well do instantaneous phase and frequency attributes predict the Matching Pursuit solutions? This paper seeks to answer these questions.
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Novel Method to Improve Seismic Resolution Through STFTHC Algorithm
Authors M. Sajid, D.P. Ghosh and Z. ZahirNovel algorithm Short-Time-Fourier Transform-Half-Cepstrum(STFTHC) is proposed in this paper to increase resolution of thin beds though broadening the frequency bandwidth of seismic. The new proposed algorithm increase the resolution without adding any high frequency noise as observed in different industry available algorithm of seismic resolution. Testing on wavelet, 1D thin layer model, 2D thin layer model and on real seismic proves is effectiveness for seismic resolution and shows high correlation coefficient with well reflectivity as compared with original seismic.
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Advances in Sedimentary Facies and Depositional Environment Analysis of the Subsurface Late Miocene Offshore Borneo Using Oil-Based High Resolution
Authors M.N.A. Bakar, M. Ismail and N.S. KhalidIn this paper, borehole image are used for a sedimentological study. More than 3600ft of image log data is subdivided into image facies related to depositional processes from which the sub-environments of a shallow marine sequence is inferred. The borehole image provides excellent examples of sedimentary features such as cross bedding, flaser bedding, lenticular bedding, bioturbation, soft-sediment deformation, and de-watering structures; capturing the high heterogeneity of the formation. These features enable us to interpret sedimentary facies in detail and classify them in terms of their depositional processes. Vertical siccession of these sedimentary facies are then associated to infer their depositional environment such as shelf, shorefaces, and beach-foreshore environments.
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Image Based Petro Physics for Thin Bed Analysis Using the Bore Hole Image Data
Authors P. Kalathingal, R. Holland and R. MartinezThe Bore-hole Image tool provides the vertical resolution required for the thin bed analysis. Image Petrophysics is one of the applications could provide the high resolution Petrophysical properties like porosity, permeability and also will provide the vertical anisotropy, grain size distribution and volumetric that aids in the better understanding of thin bed formation evaluation
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Core–log Integration for a Fractured Reservoir
By H. DürrastIn hydrocarbon exploration fractures play an important role as possible pathways for the hydro-carbon flow and by this enhancing the overall formation’s permeability. Advanced logging methods for fracture analysis, like the borehole acoustic televiewer and Formation Microscanner (FMS) are available. However, open and with water or hydrocarbon filled fractures are also sen-sitive to electrical and other conventional logging methods. The integration of core and log data from a sandstone reservoir show that fractures can be identified with conventional logging; however limitations still exist.
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Subsurface Facies Analysis and Reservoir Characterization of the Late Oligocene Penyu Formation, Shallow Marginal Marine to Low Energy Deltaics Sediments, Penyu Basin, South China Sea, Malaysia
Authors M. Johansson, S. Farag, R. Lafferty, R. Rahman and W. TanThe subsurface facies analysis was based on a single well penetrating the Late Oligocene K1 – K10 sands of the Penyu Formation in the Eastern reaches of the Penyu Basin. This well acquired an extensive data suite including; conventional wireline (gamma-ray, lateralog resistivity, density-neutron, acoustic), specialized data such as electrical imaging, nuclear magnetic resonance, elemental capture spectroscopy and dielectric propogation. In addition, the entire reservoir succession was conventionally cored and drill-stem tested. The borehole conditions were good and therefore the data quality was excellent for detailed facies analysis. The image log was calibrated to core, and detailed facies analysis was extended beyond the core using the geological features from the images, the porosity and permeability from conventional density-neutron and the nuclear magnetic tool and the mineralogy from the elemental capture spectroscopy.Three major lithological groups were identified sandstone, heterolithic and mudstone with each facies often transitional to the next. The overall depositional environment has been interpreted as restricted shallow marginal marine bay adjacent or proximal to a low energy delta or estuarine mouth.
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Statistical Analysis of Faults Attributes. Taking Into Account the Truncating and Censoring Effects
Authors D. Kolyukhin and A. TorabiA statistical analysis of single faults' attributes was performed. A truncated power-law was compared to a simple power-law approximation. We have studied the relationships between fault displacement and fault length, damage zone width and fault core width. The algorithm of statistical analysis of fractures length distribution under the resolution effect is developed.
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Turning Hazards Into Resources, Success Story from DS-1
More LessOver the last three decades, the Malaysian exploration industry has matured significantly. Despite its maturity, new plays continued to be evolved and enable PETRONAS to play its role in support of the government policies which aim to reduce dependency on oil as the main energy source. Recent discovery of a shallow gas accumulation in what was once considered a shallow drilling hazard to be avoided, has now become a new play promising substantial commercial gas resources. DS-1 has proven to be the largest shallow gas fields tested to-date, producing gas at a depth as shallow as 512m MDDF. In addition several untested reservoirs, some of which yielded gas on MDTs were encountered. The shallowest interpreted gas reservoir occurred at a depth of 404 m MDDF. The discovery at DS-1 has given impetus and forced a relook at a forgotten play in Malaysia gas exploration history. The success had changed the overall exploration strategy in PETRONAS and subsequently enhances PETRONAS resources in meeting the demand of gas in Peninsular Malaysia.
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Imaging Below Shallow Gas with Full Azimuth Acquisition: A Solution Design and Modeling Case Study in Offshore Malaysia
Authors M.C.K. Choo, M. Branston, M. Tham, P. Baltensperger and M. WysockiThe image of the target in this case study is affected by zones of shallow gas/high Earth attenuation in the overburden. The goal of the study is to determine whether the imaging of the seismic below these areas can be improved through the application of advanced acquisition designs, eg. increased azimuth, long offset acquisition. Following the successful completion of a proof of concept test using a realistic synthetic model, illumination analyses were carried out over the survey area to determine the illumination characteristics of the legacy survey and the circular shooting acquisition to help understand the impact of the shallow gas bodies on the amplitude across the target horizons. The non-conventional circular acquisition approach has the potential to improve upon the azimuthal sampling achievable with the traditional straight line narrow azimuth survey. To determine the relative benefits of the full azimuth approach against the narrow azimuth legacy data for this specific area, additional target orientated analysis was conducted. This consisted of establishing the full range of reflector dips and azimuths (outside of those in the existing structural model) which could be imaged by each technique combined with simulating local PSDM images for the key areas of interest.
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Broadband Acquisition - Imaging Below the Shallow Gas
More LessIn this deep water marine seismic dataset, it has been observed that imaging and resolution of the deep section is poor. The amplitudes of the events at depth are deemed to be affected by the shallow gas clusters. A 3D illumination study was carried out to determine the illumination characteristics of the proposed multi-azimuth acquisition geometry. Of main interest is the comparison between the amplitude maps corresponding to the conventional towed marine and broadband type seismic acquisition. The key method presented in this paper is that we have incorporated earth attenuation into the 3D model and amplitude output.
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Impact of Gas-Sands and Gas-Clouds on Wave Propagation through Numerical Modeling
Authors R. Alai, A.S.B. Saleh and M.F. AkalinIn the Malay basin often shallow gas leakage and presence of partially gas saturated sands are major issues in seismic imaging and often the presence of gas results in poor quality, low S/N-signal-to-noise ratio “washed-out” vertical bands in seismic sections causing challenges in seismic data processing and interpretation. Although gas cloud imaging may be improved through shear waves, in the following examples acoustic models have been used to illustrate the impact of internal multiples in contributing to the complexity of imaging and illumination issues in Malaysian gas-sands & gas-cloud present environments. The examples illustrated in this abstract clearly show the impact of gas-sand and gas-cloud presence on wave-propagation in a simple geological setting.
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Integrated Reservoir Characterization and Static Geomodeling of Senoro Field, Senoro-Toili Block, Sulawesi, Indonesia
Authors K.W.A. Kwartono, D. Hasanusi and R. WijayaSenoro field is a proven carbonate gas reservoir, located in the north-eastern region of Senoro-Toili Block, Sulawesi. Six wells have been tested 18-20 MMSCFD of gas rate from Miocene carbonate of Minahaki platform. A multidiscipline study was conducted by integrating geology, geophysics, petrophysics and reservoir engineer data. This paper presents reservoir characterization and static geomodeling study to identify new well proposals for further future development plan. This study was commenced with structural model configuration based on 2D seismic interpretation and well log correlation. Facies was analyzed based on core and log calibration, while at un-cored intervals, it was predicted using electrofacies approach. Porosity-permeability cross plot was formulated by incorporating facies definition. Accordingly, 3 transforms were recognized. To distribute facies and porosity, sequential geostatistic approach was applied by incorporating AI model as secondary trend, while permeability model was calculated based on aforementioned transforms. J function method was performed to estimate water saturation in the transition zone, so that capillary-gravity equilibrium was taken into account. Finally, volumetric calculation was quantified based on 3D porosity and water saturation, while permeability model was used in dynamic flow simulation. Based on the reservoir simulation, 15 new wells have been proposed for field development optimization.
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Petroleum Systems Modelling: A Case Study from Dutch Central Graben (Offshore Netherlands)
More LessExploration has seen a considerable improvement in recent years when it comes to understanding basin and reservoir geology. From regional scale to the reservoir level, integration of various geoscientific disciplines during exploration increases the understanding of critical parameters reducing risk significantly. By integrating geological, geophysical, petrophysical, and reservoir data one can model the evolution of basin and petroleum systems with time. To improve the understanding of petroleum system elements, 3D petroleum systems modeling of the Dutch Central Graben was performed. This helped in understanding of how a reservoir has been charged with hydrocarbons; including the source and timing of hydrocarbon generation, migration routes, quantities, and hydrocarbon type in the subsurface. Hydrocarbon accumulations were observed in the Lower Graben Sandstones and the Greensand Reservoir units, within different structural traps. Predicted modeling results agree with some of the discovered fields in F3 block, of which the F3-FB field proved to be economically viable and has been producing commercial quantities of hydrocarbons since last 3 decades.
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Sequence Stratigraphic Approach to Identify Upside Potential in Matured Block Sk307, West Baram Delta, Sarawak
Authors D.H. Sapri, W.C.H. Wong, A. Chuang and O.A. MahmudThe sequence stratigraphic study of matured Block SK307 in the West Baram Delta is documented and its sequence refined. Integrating various data, the study has established a new stratigraphic framework in the area. Up to eight sequences has been recognized that cover the Miocene through to the Present. A conceptualized petroleum system model is presented and the upside potential traps in this area are also highlighted and discussed for further exploration.
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