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Abstract: Government-owned PetroSA, South Africa, was formed from the merger of Mossgas, Soekor (oil exploration) and the Strategic Fund (oil stocks) in 2002. From Mossgas it inherited an offshore production platform feeding an onshore gas-to-liquids (GTL) plant. This paper describes the evolution of a predominately synthetic motor fuels producer (Mossgas) born in the 1980's during the sanction years and energy crisis, to the PetroSA GTL plant today producing fuels and value-added chemicals. The low sulphur and low aromatics Syn-products are well-proven and world leading quality. This Mossel Bay installation situated at the southern tip of Africa is the world's largest commercial GTL plant. The natural gas and associated condensate feedstock is supplemented by imported condensate to produce 36,000 barrels of refined products daily. The manufacturing process entails the conversion of natural gas to synthetic liquids through steam and oxygen reforming and the HTFT (high temperature Fischer Tropsch) process (licenced from Sasol) followed by refining of the liquids and condensate through conventional processes. In addition to fuels production (90%) ranging from propane to heavy fuel oil, the GTL facility contributes approximately 15% of PetroSA's total revenue through production and export of 60 million litres speciality distillates and about 135 million litres alcohols that are produced as a by-product. The exceptional quality of distillates produced allowed in-house marketing and technical development of high value niche speciality chemicals. Future GTL plans includes expanding production into petrochemicals, e.g. the HTFT highly olefinic gaseous by-product propylene can be converted to products such as acrylic acid and acrylates which will add further to the bottom line in future. Plans are well advanced to secure future gas feedstock post 2008 both from indigenous offshore sources and imported LNG. INTRODUCTION The Government-owned "The Petroleum Oil and Gas Corporation of South Africa (Pty) Ltd" (PetroSA), Mossel Bay, South Africa, operates an offshore production platform to feed its onshore ISO 14001 and 9001 compliant gas-to-liquids (GTL) plant. Figure 1 shows the location of the installations. This Mossel Bay installation situated at the southern tip of Africa is the world's largest commercial GTL plant today that uses natural gas as feed. (Figure in full paper) The natural gas and associated condensate feedstock is supplemented by imported condensate to produce 36,000 barrels of refined products daily. This is equivalent to 50,000 barrels of crude oil a day and amounts to about 7% of South Africa's liquid fuel needs. In addition to fuels production, PetroSA manufactures unique products. Approximately 15% of PetroSA's total revenue is obtained through production and export of 60 million litres speciality distillates and about 135 million litres alcohols that are produced as a by-product. PetroSA's GTL technology is recognised around the world for producing the "cleanest fuels" through an environmentally responsible process that releases minimal emissions. This is one of the reasons why PetroSA's petrochemicals and fuel products are in growing demand in the international market. Plant History The sanction years in the 1970's and 1980's created an ideal breeding ground in South Africa for the development of strategic projects.
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Energy > Oil & Gas > Downstream (1.00)
Abstract: A majority of industry operators and service companies have adopted directional drilling collision avoidance rules based on stringent controls to prevent surface collisions and consequent human and environmental damage. These rules are found to be severely restrictive for the optimal positioning of wells through deeper reservoir zones where the level of damage from collision can be contained. A new method is proposed that retains existing rules for avoidance of shallow (severe outcome) collisions and provides the option for use of risk based rules in deeper sections of wells where the outcome of a collision would not be as severe. The risk level of collision with respect to any offset well is calculated and then converted to a Risked Clearance Factor, an established standard for evaluating different levels of collision tolerance in wells. Deep intersections have several characteristics which require separate treatment from shallow intersections. They have high convergence angles which minimize the physical space and distance where a collision may occur and they have lower economic risks of a collision relative to the cost of corrective action. This method has been implemented in a field area of rapid prospect planning and development. The rules are designed to be simple and practical in order to reduce planning and drilling cycle time. A matrix of risk elements, specific to the field area is presented for different depths of collision to help to derive the level of tolerable risk. A case history is presented that shows the clear benefit of utilizing the alternate method. Background Chevron's Thailand Business Unit (COTL) had previously identified multiple instances where Asset teams desired to position a development well close to an abandoned exploration well in order access the maximum volume of potential reserves. In many of these instances, the well planning team in the Drilling group was unable to deliver a well in the desired target location(s) due to constraints imposed by the existing Collision Avoidance policy. In some instances a significant decrease in Net Present Value was realized due to the less than optimal reservoir position. Both the Asset and Drilling teams identified the need to develop alternate methods for placing a well in the most desired location in order to access the most reserves while still maintaining a safe working condition. In addition to the above, it was also identified that the existing Collision Avoidance policy included provisions for closing in and depressurizing producing wells adjacent to active drilling wells. While this practice (to varying degrees) is standard throughout Chevron and the industry in general, it was felt that a review of COTL's current practices was required in order to insure that the policy was not over conservative. The upside of this analysis would be less shut-in days for adjacent wells translating to fewer days of deferred production. With these drivers in mind, a project team consisting of COTL and Chevron Corporation Energy Technology (ETC) personnel was formed to investigate an alternative collision avoidance methodology specific to the unique nature of the COTL drilling environment.
- North America > United States (0.46)
- Asia (0.34)
- Europe (0.28)
- Overview (0.87)
- Research Report > New Finding (0.46)
Abstract: The determination of Sulphur in fuels (diesel and petrol) by means of EDXRF is a standard method of modern analysis. New environmental regulations require a constant improvement of the detection sensitivity. The analytical instrument the SPECTRO XEPOS has a detection limit of < 1mg/g S. In addition to the analysis of the element S, the detection method utilized in the XEPOS allows for the simultaneous analysis of other trace elements, such as Si, Cl, K, V, Fe, Ni, Cu, Zn. The use of online analytical systems and smaller bench top instruments in the petroleum industry will also be presented. Spectro AI produces several types of spectrometers for the analysis of trace elements in petroleum products. These instruments range from simple bench top models for the analysis to on-line systems for the analysis of up to 7 streams. The Spectro Phoenix, a bench top model, is capable of analysing the maximum of 6 elements per mode. Common elements that the systems can be configured for are S, V, Fe, Ni and Pb in petroleum products. (Table in full paper) The Spectro iQ, launched at Pittcon 2005, is a compact Polarized XRF spectrometer capable of determining elements from Na to U in solid, liquid and powder samples. The spectrometer has been optimised for specific applications such as petrochemical products. Polarised excitation results in the scatter from the X-Ray tube being eliminated which improves peak to back ground ratios and thus yields lower detection limits. The Spectro iQ is equipped with a close coupled curved crystal design, (C-Force technology) which focuses more of the polarised X-rays and yields more efficient fluorescence. In addition, the spectrometer is fitted with a precision made sample presentation device that eliminates errors associated with traditional ED-XRF turntables. Detection limits of 0.5ppm S in automotive fuels can be achieved with this system. The Spectro XEPOS, also a polarised ED XRF spectrometer and is fitted with three secondary targets to optimise the three regions of the periodic table - i.e. light, medium and heavy elements. These targets are HOPG, Mo secondary target and Barkla Scatter Aluminium oxide. (Table in full paper) Conclusion Spectro Analytical Instruments offers a wide range of analytical equipment for the analysis of Sulphur, lead and other trace elements in petrochemical products. New environmental legislation worldwide requires constant improvements in detection limits of toxic elements such as S and Pb and Spectro's ED-P-XRF spectrometers meet these requirements.
Research On Chemical Shallow Profile Modification Mode of Frontal Facies Reservoir of Daqing Oilfield of China
Jiang, Huaiyou (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Sui, Xinguang (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Liu, Yingping (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Liu, Junshu (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Zhai, Chunfeng (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Dou, Hongwu (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Li, Liping (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Song, Lijun (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Shang, Mei (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Cai, Jianhua (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd) | Tian, Fengshun (Geological Institute of No.1 Oil Production Company in Daqing Oil Field Company Ltd)
Abstract: The technology of Chemical Shallow Profile modification is an important means in adjustment on water injection structure. The GaoTaiZi reservoirs in the Daqing oilfield of China are mainly delta frontal facies sedimentation, there are many fine layers in longitudinal profile with 92 sedimentary units. With GaoTaiZi reservoir entering into high water-cut period and its development time prolonged, the problems of contradiction between longitudinal zones are becoming more and more prominent. But the thickness of separation layers are less than 0.4m, the room for layers subdivision of injection wells is very small, it becomes difficult to carry out oilfield development and modification. Combined with the sedimentary characteristic of river-delta reservoir and the study result of flow unit, Vadose feature of delta frontal facies sedimentation reservoir in Daqing Oilfield is studied in this paper. Whether the chemical shallow profile modification effects are good or bad is mainly determined by the distribution of ancient current. The paper studies the distribution rule of ancient current and carries out reservoir description. It classifies the ancient current in sedimentary microfacies (single sandbody), carries out chemical shallow profile modification in ancient current, perfects the relationship of injection and production well in ancient current and improves development effects. After chemical shallow profile modification, adjustment effect is different in oil wells of various vadose directions, base on this principal?profile modification mode in main flow zone of sedimentation system of delta frontal facie in the Daqing oilfield is set up, the thought and ways of selecting wells and layers in delta frontal facies to carry through profile modification is put forward. great economic and technology effect is get and it has wide application prospect. Background information of regional geological characteristics This region is located on middle Saertu anticline structure. On vertical section plane it is divided into 4 oil reservoirs formation 26 (subzone) packages 92 small beds. In development we divided it into G I, G II, G III, G IV four bed system and use inverted 9-spot square pattern exploitation. Here GaoTaizi formation has the characteristics of have several oil reservoirs, the permeability among them is quite different And oil reservoir is seriously heterogeneous. Detailed l reservoir comparison and division and Research on Vadose Geological Charatceristic Based on S+Ppay zone with 92 vertical sedimentary units and subdivision 4 sedimentary microfacies: distriburary fluvial sandbody, tabulated sheet sand, untabulated sheet sand, under water mud. combined study results both at home and abroad, drawing out sedimentary microfacies distribution maps and typical sandbody section maps, distributing different types of fluvial-deltaic secimenrary microdacies and sandbody macroditribution at different sedimentary conditions, showing geometric shape of different sandbody, distribution rule and their connection type with other sandbodies, setting up 4 types fluvial-deltaic fine geological models There are 5 types in delta front facies, they are inner delta front branch sandbody model, inner delta front branch-massive transitional sandbody model, inner deltaic massive sandbody model, outer delta front stable sheet sandbody model and outer delta front unstable sheet sandbody model.
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.36)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Yian Formation (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Mingshui Formation (0.99)
Abstract: In the early 90's Statoil had to find a non-flaring solution for an associated gas field (Heidrun) on the Norwegian Continental Shelf. Different gas solutions were considered and in 1997 Statoil commissioned and started up a world scale methanol plant (Tjeldbergodden). The synthesis gas production is based on combined reforming technology (licensor HTAS) and the methanol synthesis is based on a boiling water methanol reactor system (licensor Lurgi). With respect to increase the production and efficiencies, new technology elements have during the recent years been developed and implemented. The plant shows very high on stream factor (from 96 to 98 % over the last three years) and productivity, and ranks as the most energy efficient (> 70 %) methanol production facility in the world. It should be kept in mind that a high-energy efficient methanol plant is a "stiff system" to operate and therefore it is even more challenging to obtain a high on-stream factor than normally for less energy efficient facilities. Statoil has during the last 5 years studied different concepts for increasing the methanol production capacity. The focus on using more of the natural gas from the Norwegian Continental Shelf and the need for more electricity, resulted in an integrated gas power (Combined Cycle) - methanol concept. Different synthesis gas (Gas Heated Reforming, Compact Reforming, Autothermal Reforming and Conventional Steam Reforming) and methanol concepts have been technically evaluated and the project ended up with conventional steam reforming (HTAS) and a boiling water reactor system (Lurgi). Planned start up is 2008. INTRODUCTION Statoil and Conoco discovered the Heidrun oil field in 1885. It achieved commercial production in 1995. The field contained large quantities of associated gas, which could not be flared. Natural gas had to be converted into a transportable liquid or re-injected in the oil field. Different gas solutions were considered and in 1997 Statoil commissioned and started up a world scale methanol plant (Tjeldbergodden). The Heidrun field was distant from existing pipelines, however. It is in the Haltenbanken sector, south of the arctic circle, about 200 km from the Norwegian coast and about 600 km northeast of the closest point of the existing North Sea gas pipeline grid. After evaluating several alternatives, Statoil and Conoco, decided in 1990 to construct a 250- km, 0.4 m (16in.) pipeline to shore at Tjeldbergodden and build a methanol plant there. The pipeline has been designed to transport up to 2.2 billion sm/year of natural gas. The methanol plant consumes about 0.7 billion m/year of natural gas. Methanol may be seen as a gas solution for medium size gas fields (1โ4 G).New business opportunities will materialize depending on the methanol production cost. Methanol is shown to have potential as a fuel component for both fuel cells and gas turbines both with respect to production cost and technical use, and may become a feedstock in the production of olefins and dimethylether (DME).
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/8 > Heidrun Field > ร re Formation (0.99)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/8 > Heidrun Field > Tilje Formation (0.99)
- Europe > Norway > Norwegian Sea > Halten Terrace > Block 6507/8 > Heidrun Field > Ile Formation (0.99)
- (5 more...)
- Health, Safety, Environment & Sustainability > Sustainability/Social Responsibility > Sustainable development (1.00)
- Health, Safety, Environment & Sustainability > Environment (1.00)
- Facilities Design, Construction and Operation > Natural Gas Conversion and Storage > Liquified natural gas (LNG) (1.00)
Abstract: A lithoseismic characterization allowed us to map sandstone distribution preditected through seismic facies analysis and to characterize the porosity. Well data alone cannot accurately recover the requested property variations, because of their sparse lateral distribution and their large spacing, compared to the size of the lateral heterogeneities to be modeled. On the opposite and despite its poor vertical resolution, seismic data provide valuable information to overcome such a limitation as it benefits from the highest lateral density of information. Accurate descriptions of the lateral variation of reservoir heterogeneities is a critical issue when generating reservoir models dedicated to history matching and subsequent production forecasts. This poster describes one of the workflow that has been successfully applied on a turbidite in Angola, which allows (1) extracting reliable constraints from post-stack seismic amplitudes and (2) incorporating them into high-resolution geological models for quantitative lithoseismic reservoir characterization. Relevant constraints are generated using lithoseismic reservoir characterization techniques, based on seismic inversion followed by seismic facies analysis, generation of net-to-maps and porosity models. Then, for reservoir geological modeling, we selected a pluri-gaussian modeling approach, which provides the requested level of flexibility for mixing the obtained map with well data and thus solving the downscaling issues. Case study The example used for illustrating the modeling workflow described in this poster is a turbidite field, Deep water Offshore Angola. The data set used is the following:โ3D post-stack seismic volume; โ8 wells with a full set of logs, including sonic, density, gamma ray, resistivity and neutron porosity; โThe reservoir top and bottom in both time and depth. Extracting the relevant seismic constraints The quantitative lithoseismic characterization work starts with a two approaches:Qualitative constraints, when inversion is followed by seismic facies analysis. Interpreted seismic facies maps are used to define the geological zonation of the reservoir. Quantitative constraints consist of facies/geological rock type proportion maps, generated from geological calibration of post-stack seismic attributes at wells and statistical regression of geostatistical modelling techniques. In the example used for to illustrate this poster, both kinds of constraints have been used simultaneously. No reliable quantitative relationship can be built between seismic attributes and reservoir properties at wells, because the heterogeneity of the reservoir under study. Consequently, a seismic facies analysis is performed to obtain a reservoir zonation map. This map is then converted into sand proportion map by calibrating the seismic facies against well data. The technique we used is a non-supervised statistical pattern recognition approach, based on the analysis of the multivariate probability density function of the seismic attributes. This analysis allows identify the number of natural clusters in the data, each mode corresponding to a specific shape of the traces. The most typical traces of each mode are extracted and then used in discriminante analysis. At this step two maps were generated: a facies map and a probability map that gives information on the confidence in the classification.
- Africa > Angola (0.97)
- North America > Canada > Alberta > Woodlands County (0.25)
- Geophysics > Seismic Surveying > Seismic Processing > Seismic Migration (1.00)
- Geophysics > Seismic Surveying > Seismic Interpretation (1.00)
ABSTRACT Degradation of oil is a most important part of the MEOR. This procedure can reduce the oil's viscidity and freezing point and improve the oil's fluxion in-situ. This paper shows the encouraging results of the microbial degradation on the heave oils gathered from Qihai and Xingjiang oil fields in China. The results show that the bacteria can efficiently improve the property of the oils. After microbial treatment, the gum & asphalt content of the oils are lowered at above 9% and their structure is also changed. The ฮฃnC21-/ฮฃnC22+ of the oils are enhanced through the microbial treatments and the shapes of oils in solution are changed greatly. The oils' viscidity and freezing point are reduced about 15% and 20% respectively, with production increments ranging from 8.53% additional ratio from 35.72% additional ratio and the hot oiling frequencies of oil wells reduced at least 2.3 times. The average date production of the test wells in Xingjiang oil fields from 2.39 T before the treatment to 14.196T after the treatment, the ratio of cost to output with is 3.14 time higher than that of the microbial treatment. This technology proves to be feasible and economical in these oil fields. Heavy oils are rich in gum and asphaltene, and they have the characters of high freezing point, low flow ability, difficult oil recovery and high recovery cost . Microbe can improve the physical features of heavy oil in two aspects:by degrading the components with big molecular of heavy oil, microbe can decrease the average molecular weight of heavy oil; and the metabolite derived from microbe, such as biological surface active substance, acid, gas and so on, can decline the viscosity of oil considerably. Gum and asphaltene are components with biggest molecular weight and most serious polarity in heavy oils, meanwhile they are one of the main factors making the difficulty of oil recovery . Usually, microbe can hardly degrade them . Confronting this situation, the authors separated and bolted lots of microbe from environments rich in petroleum microbe, and through the bolting conditions control, drew out a series of mix bacteria, which can effectively degrade heavy oil, even gum and asphaltene; these microbe has been used to lower the viscosity and freezing point of heavy oil for the goal to improve physical and chemical characters of heavy oils. Several experiments of microbial enhancing oil recovery (MEOR) have been carried out in Qinghai Oilfield and Xinjiang Oilfield, China. Samples and experimental method The effective mix bacteria bolted are mainly bud bacillus, bacillus brevis, pseudomonas and coccus. In the experiments, the crude oils are mainly mentioned and analyzed from Well Xian 19, Well Qizhong 22 respectively belonging to Huayanshan Oilfield and Qigequan Oilfield of Qinghai Oilfield Corporation, and from 97 and 98 Block of Xinjiang Oilfield Corporation; the crude oils are used in repeatability experiments from Qinghai Nanyishan Oilfield, Shengli Dongxin and Jinjia Oilfield, and Liaohe Ciyutuo Oilfield; density of the oils is 0.93 to 0.96g/cm, and the content of gum and asphaltene is more than 35%.
- Research Report > New Finding (0.34)
- Research Report > Experimental Study (0.34)
- Asia > China > Tianjin > Bohai Basin > Huanghua Basin > Dagang Field (0.99)
- Asia > China > Qinghai > Qigequan Field (0.99)
- Asia > China > Qinghai > Qaidam Basin > Qinghai Field (0.99)
- (3 more...)
Abstract: IMO has declared the Gulf area amongst the most sensitive areas in the world. Despite this declaration the Gulf experienced many detrimental impacts in the past two decades that could endanger its environment and habitat. Add to that the sea transportation of oil, drilling companies, and oil leakage. All those factors jeopardize the already sensitive environment of the Gulf area. This paper will focus on defining some of those factors and highlight its effect on the Gulf. INTRODUCTION The MARPOL 73/78 Convention defines Special Areas as "Areas with special ecological conditions, considered to be so vulnerable to pollution, that far reaching and mandatory regulation should be applied for their protection against Oil Spills". Examples of those special areas are "Mediterranean Sea, Baltic Sea, the Gulf and the Black Sea, etc. IMO prohibits the discharge of any pollutants of any kind into those water bodies, and sets stringent criteria for the prevention and the preservation of their Ecology. The 1973 IMO Convention sets these criteria and clearly defines the limits of admissible concentration of these pollutants. The IMO convention contains five (5) Annexes which deal with the following pollutants:-Annex I- Oil Annex II- Noxious Liquid Substances carried in bulk (e.g. Chemicals) Annex III- Harmful Substances carried in packages (e.g. tanks & containers) Annex IV- Sewage Annex V- Garbage The IMO stipulates that by ratifying the Convention, the ratifying Government(s) is adopting Annex I, and annex II, whilst Annexes III, IV, and V are optional. In addition to the fact that the Gulf is considered to be a Special Area, it is estimated by the U S Geological Survey that two thirds of the conventional oil reserves lie in the Middle East and one half of the unconventional oil is thought to be available there also. This oil is mainly either produced or transported from the Gulf Region. This necessitates the presence of Oil Wells and Oil Drilling Companies with all the chemicals used for drilling and work over followed by the transportation of oil. Although control and regulation could be applied to all those possible threats, one major threat could not be controlled or dealt with, which is the deliberate pollution of the Gulf Area by mankind. This paper is solely devoted to highlight the major pollution threats to the Gulf Area, and defines measures to combat those threats. The Gulf The Gulf is a partially closed body of water with an average depth of thirty-five meters (35m) located between the Gulf Co-operative Council and the I.R of Iran. The gulf is orientated in a northwest to southeast direction and is approximately 917 km (570 miles) long, with a maximum width of about 338 km (210 miles). The Gulf has a very limited source of fresh water - primarily the Shatt-al-Arab River which is the merge of the Tigris & Euphrates Rivers. The Gulf is connected to the Gulf of Oman, the Arabian Sea, and then the Indian Ocean via the Straits of Hormuz.
- North America > United States (1.00)
- Asia > Middle East > Iran (0.55)
- Asia > Middle East > Saudi Arabia (0.47)
- Asia > Middle East > UAE (0.34)
- Transportation > Marine (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.87)
- Asia > Middle East > Pakistan > Arabian Sea (0.89)
- Africa > Somalia > Indian Ocean (0.89)
Abstract: Reshadat oilfield is located in the central Part of the Persian Gulf. This field is an anticline with an approximately North- South trend. The Upper Sarvak Formation is a potential reservoir in this area. Mishrif resvoir in this field has been divided into five zones. Zone A, (the uppermost) is recognized the best reservoir zone. Diagenetic processes including (desolation, dolomitization and fracturing) improved reservoir qualities. As a result of diagenetic process (dissolution), stratighraphic trap (diagenetic) has been created, and zones A and B are shaped into pinch out trap. Weathering dramatically improves the reservoir permeability and thus controls the extent of this diagenetic trap. Investigation shows that local unconformity in the southern flank of Reshadat oilfield, created the highest reservoir zones in this part. Consequently; reservoir quality of zones C and D have been improved. The inversion of the seismic data to acoustic impedance has allowed for better definition of the main lithological units. Depth conversion has been performed and accurately ties the interpreted horizons to the available well data. The inverted impedance clearly highlights facies and porosity variations within Mishrif interval which not apparent on seismic data. The combination of seismic interpretation and seismic inversion has improved our understanding and definition of the Mishrif reservoir. Applying reasonable cutoffs for porosity and permeability, reveals valuable zones (A&B) in this portion of field. These zones are located in the west and northwest of Reshadat oil field. The study shows that thickness of the valuable zones are increasing towards the west and the northwest and decreasing in the center and south of this field. INTRODUCTION The study has taken the form of an initial interpretation data followed by an inversion to acoustic impedance and subsequent fine-tuning of interpretation on the impedance data. The advantage of this offers is a reduction of wavelet and tuning effects and the generation of 3D geological model matching the original seismic data. In addition reservoir properties such as porosity can be estimated from products of the inversion process. The main results of the study are time and depth maps of horizons (Figs.1, 2): near top Damam, top Mishrif, top Khatiyah, top Kazhdoumi and etc. In addition 3D acoustic impedance are generated in time depth. (Figure in full paper) Depositional setting Mishrif - Khatiyah Formations:Mishrif reservoir contains several lithologies. Each of which exhibits differing sedimentological, and petrophysical properties and each representing a distinct subenvironment. Interfacies boundaries are not clear because adjacent facies grade laterally and vertically into each other. The formation consists of the following facies: Lagoonal/ back reef, rudist biostrom, algal boundstone, shallower sub basinal (or outer reef margin), and deeper sub-basinal (slope margin) .The contact between Mishrif shallow marine reef facies and khatiyah deeper marine facies in a gradual transition (Fig.4). There is thinning of the Mishrif on the crest of structures. This is largely related to the erosion during early upper Cretaceous uplift. It is believed that most of the present structures originated during upper Cretaceous uplift. The Khatiyah formation consists of interbedded limestone and shale with a total thickness averaging 120m in the Reshadat.
- Geology > Sedimentary Geology > Depositional Environment > Marine Environment > Reef Environment (0.55)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.52)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Dolomite (0.36)
- Asia > Middle East > Qatar > Arabian Gulf > Rub' al Khali Basin > Reshadat Field (0.99)
- Asia > Middle East > Qatar > Arabian Gulf > Arabian Basin > Arabian Gulf Basin > Block 6 > Al Khalij Field > Mishrif Formation (0.99)
- Asia > Middle East > Qatar > Arabian Gulf > Arabian Basin > Arabian Gulf Basin > Block 6 > Al Khalij Field > Laffan Formation (0.99)
- (3 more...)
Abstract: Deep-water basins such as those found offshore West Africa, the Guld of Mexico and other locations offer great promise in satisfying the world's growing need for oil and gas reserves. At the same time, they pose special challenges in finding, developing and producing the reserves to realize this potential. Traditionally, 3-D seismic surveys have been a main factor in reducing risk and lowering costs in both exploration and production. Now, new-generation surveys involving Q-Technology are proving that higher resolution and improved control and fidelity significantly improve reservoir imaging over conventional seismic data. In particular, applications of Q-Technology promise to lower costs and reduce risk for offshore West Africa exploration and production. Deep-water seismic data are often plagued by reverberations that can obscure the primary information. The sensitivity and fidelity of Q data allow these reverberations to be attenuated to reveal the underlying geological structure and rock properties. A second important challenge in deep-water plays involves seismic imaging around salt. In this regard, Q data provide better penetration and imaging in salt tectonic environments. Although current drilling targets in West Africa are not generally pre salt, nevertheless, imaging beneath salt is important in understanding the petroleum system since delineating source rocks and migration paths can be critical for field development. Moreover as West Africa matures, sub salt plays likely will become important. Finally, the high resolution of Q data is proving seminal in early field development by identifying potential permeability barriers. Indeed, the results obtained in such early stages of field development promise that the value of Q data can be realized even earlier in the process. By using Q technology in the exploration phase, Q information can be used in locating first targets and in the planning of facilities, _ INTRODUCTION Deep-water basins offer great promise in satisfying the world's growing need for oil and gas reserves. However, although the rewards can be great, the financial and safety risks are enormous. Traditionally, 3-D surveys had been the main factor for reducing those risks, but new-generation 3-D and 4-D surveys utilizing Q-Technology* are now making further strides. There are many features that distinguish this new technology. The four most prominent ones are the Calibrated Marine Source (for determining the far-field wavelet at each shotpoint), the acoustic positioning system (for accurately measuring the locations of the hydrophones), the streamer steering system (for mitigating feather and maintaining constant streamer. separation), and single-sensor recording (for finely sampling the signal and noise wavefields). This paper discusses how these aspects of Q-Technology favorably influence the reduction of risk in deep-water surveys. High-resolution surveys. High-resolution surveys In an empirical study, Kallweit and Wood (1982) observed that when at least two octaves of bandwidth are present in a white, zero-phase, noise-free wavelet, the temporal resolution is determined solely by the maximum frequency component in the wavelet. In towed streamer surveys, that maximum frequency value is largely dictated by ghost filters associated with the depths of the sources and receivers. Shallow tow depths allow high frequencies to be passed.
- Africa > West Africa (0.86)
- Europe > United Kingdom > North Sea (0.71)
- Geology > Structural Geology > Tectonics > Salt Tectonics (0.68)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.54)
- Europe > United Kingdom > North Sea > Northern North Sea > East Shetland Basin > PL 123 > Block 211/19 > Murchison Field > Brent Group Formation (0.99)
- Europe > United Kingdom > North Sea > Northern North Sea > East Shetland Basin > Block 211/7a > Magnus Field > Kimmeridge Formation > Magnus Formation (0.99)
- Europe > United Kingdom > North Sea > Northern North Sea > East Shetland Basin > Block 211/7a > Magnus Field > Kimmeridge Formation > Lower Kimmeridge Clay Formation (0.99)
- (5 more...)