Integrated Subsurface Study to Convert Upside Intrabeta Subzone Stakes into Additional Main Targets in Tunu Gas Field, Mahakam Delta, Indonesia

"Intrabeta" is a subzone located in the upper part of Tunu Main Zone between MF3-MF6 regional stratigraphic marker. Total cumulative production from this subzone is at 51 Bcf of gas and 4.96 MMBbl of oil. This interval is situated between Tunu Shallow Zone and Tunu Main Zone, which are the main producing intervals of Tunu Field, a giant mature gas field in Mahakam Delta, Indonesia. With Intrabeta reservoir depositional context more dominated by channel facies and more varied production fluid properties, the development of Intrabeta subzone became more challenging and previously classified as upsides. As Tunu Field is getting more matured, the challenge to deliver infill wells that economically profitable become more arduous. Thus, all attempts to give additional value to the future infill wells should be properly assessed. This paper aims to provide a comprehensive summary of how strategic collaboration between static and dynamic synthesis of Intrabeta subzone has given additional contribution in Tunu Field continuous value creation process. The method started by conducting an extensive post-mortem review on all perforated reservoirs in Intrabeta subzone. Insights from the perforated reservoirs that comprise of production behavior, perforation success ratio, cumulative hydrocarbon production and updated portfolio are then utilized to provide initial prolific area map for future candidates maturation. Data coming from the dynamic analysis were then combined with static depositional analysis on how the hydrocarbon was distributed in Tunu Intrabeta subzone. A new structural map that has been corrected from seismic push-down effect due to shallow gas presence above Intrabeta interval was then utilized to map the structurally promising area. Deterministic channel boundaries and possible sweet spots are then identified and ranked based on the development confidence level. Four wells with additional stakes from Intrabeta subzone have been proposed and drilled in Tunu Main Zone. All wells have successfully found the targeted Intrabeta targets with various post-mortem findings. While in some wells significantly better post-drilling results were encountered, in other cases slightly lower results were found due to static channel development and fluid dynamic uncertainties. All the lesson learned gathered from the pilot wells provide valuable insights on future improvement toward better and more robust Intrabeta candidate maturation methodology. The insights gained from this study have given essential understanding of Tunu Intrabeta subzone characteristics and possible future potentials. Furthermore, this paper provides a comprehensive summary, systematical approach and lesson learned in enhancing previously upside potential of Intrabeta subzone in Tunu Main Zone to compelling additional targets in Tunu Main Zone future wells as part of the continuous value creation process in a giant mature gas field.

Integrated Dynamic Synthesis as Key Success to Sustain Oil Production in Mahakam: Case Water Flooding Project in Handil Field

The Handil field is located in the Kutai Basin with an anticlinal structure consisting of a vertically stacked reservoirs deposited in a fluvial-deltaic environment. The field has been producing since 1974 under active aquifer drive followed by peripheral water injection which resulting in a high recovery factor of oil production. Cumulative oil production is more than 900 MMbbls and currently the field is still producing at 15000 bopd. The Handil Main zone is the main contributor that accounts for 60% of the Handil Field production and based on the results of new wells drilling, there is still potential of the remaining oil accumulations. Therefore, an integrated subsurface study is needed to further increase recovery in the Handil Main zone. This paper will discuss the process used to locate unswept oil in the high water cut reservoir to extend the water flood project. Waterflooding became an important part of the Handil’s development strategy to maximize oil recovery and to maintain oil reservoir pressure, as more and more fields are matured as part of their production life cycle. The main challenge is to identify area of unsweep oil that are affected by water injection activity. Understanding the reservoir behavior of the water injection sweep characteristic can significantly improve the understanding of the distribution of unswept oil in the reservoir. A robust integrated methodology was developed to identify unswept oil area by integrating Static- dynamic synthesis, 3D static model, production history, reservoir connectivity, recent well logs data and reservoir simulation. Multiple QC of oil sweet spot are done by comparing the sweet spot area of dynamic synthesis with reservoir simulation. Detailed well correlation were performed to identify the optimum water injector placement to improve the recovery factor. The results of the integrated dynamic synthesis are used to identify the sweet spot area and the optimum well injector location that will be used for the water flooding development project to be executed in 2022. The results of the study will sustain Mahakam production in the future.

Analysis of features of the design of a screw feeder for the purpose of improving its work

Feeders are an integral part of the modern technological process, they establish and regulate the pace of production, ensure its rhythm, contribute to increased productivity and increase output. The aim of the article is to investigate and analyze the types of feeders, in particular the design features of a screw feeder, to determine its advantages and disadvantages. In order to increase the efficiency of the screw feeder, to propose a way to improve its design based on the modernization of the screw. The types of feeders are considered in the article, and the main attention is paid to the study of the advantages and disadvantages and design features of the screw feeder most common in technological processes of various industries as the simplest in design and often structural features of screw feeders in modern sources, which showed that the issue of the screw configuration screw feeders are not adequately studied in terms of uptime and the factors affecting this aspect indicate relevance. Currently, in the works of modern domestic authors and in the industries of various industries, waste-free screw feeders are considered. The article describes in detail these feeders developed by TechTron in two versions - the gutter and pipe. Today, there are also studies of a screw conveyor with additional blades on the spirals of the screw, in which the relationship between its structural and functional parameters is established. An analysis of the considered design features of existing screw feeders in modern sources has shown that issues of design features, namely the configuration of screws of screw feeders, have not been studied enough in terms of uptime and factors affecting this aspect, indicating the relevance of this issue to solve a specific problem of increasing work efficiency. The advantages of screw (screw) feeders compared to other types of feeders, such as continuity of supply, tightness, simplicity of design, the ability to create excess pressure at the outlet of the screw, the ability to aggregate with other equipment in industrial plants, have led to their widespread use in many industries in various technological processes.The main disadvantage of screw feeders is the low productivity due to the communication of the auger blade of the transported material, not only translational motion, but also rotational, which leads to turning the material together with the auger. Also a disadvantage of screw feeders is the rapid operation of the screw and the loading pipe due to overloads. To increase the efficiency of the screw feeder and eliminate one of its most important shortcomings - sensitivity to overload, resulting in accumulation of material inside the chute, stopping the feeder and reducing its performance and operational reliability, screw configurations were changed. Namely, the advanced screw was divided into two zones A - the loading zone, B - the main zone of the screw. Such a structure has a spiral surface and a cylindrical casing of smaller diameter D1 in the loading zone than the diameter of the spiral surface and a cylindrical casing in the main zone D2 of the screw feeder. The advanced design of the screw feeder works as follows. During loading of the feeder, the bulk material fills the entire space under the loading device with a continuous flow, including the spiral surface D1 of the screw. When the screw is rotated, the material completely filled the cylindrical casing with a diameter of D1, having a fill factor of j1 = 1, moves in a continuous flow through section A. When approaching the material to section B, by increasing the diameter of the spiral surface to D2, the fill coefficient decreases to j2, which ensures the operation of the screw feeder without accumulation of material and increases its operational reliability.

Pathogenic complexity of septoria spot disease of wheat in northern Kazakhstan

Northern Kazakhstan is the main zone of spring wheat cultivation where, 85 % of the cultivated area is located. There is not a single variety resistant to Septoria spot among the varieties approved for use. The frequency of epiphytoties of wheat diseases in the northern part of Kazakhstan is four cases every ten years. During the years of epiphytotic development of brown rust and Septoria spot with the dominance of a particular disease, the yield of spring wheat is reduced by 25 % or more. Knowledge of the species composition of pathogens of Septoria spot allows a more focused approach to the study and creation of varieties of wheat resistant to this disease. The aim of the research is to study the species of Septoria spot pathogens in wheat in Northern Kazakhstan. In 2018–2019, the pathogenic complex of the causative agents of wheat Septoria spot was studied. The collection of leaves affected by Septoria spot was carried out on spring wheat varieties in the steppe, forest-steppe zones of Northern Kazakhstan. The species composition of Septoria pathogens was determined from microscopic preparations from the collected samples; which were represented by three types of septorial fungi: Septoria tritici, Stagonospora nodorum, Stagonospora avenae. In the steppe and forest-steppe zones of Northern Kazakhstan, the dominant species was S. tritici followed by S. nodorum.

A Success Story of Unlocking Depleted Channel Reserves in Tunu Gas Field, Mahakam Delta, Indonesia

Crestal part of Tunu Main Zone has been heavily developed with infill wells mainly targeting the isolated bars, while channel reservoirs in western flank have been depleted and considered as upsides. A novel strategy in targeting depleted channel reservoirs is initiated to challenge the conventional gridding method. The workflow comprises of integration of channel geometry update with current static data, connected gas in place reconciliation, production history, pressure update, and water rise analysis. These become key points in geological mapping of the channel which helps to identify remaining potential channels in the field. The recent result of four wells that have been drilled targeting the depleted channels in Tunu Main Zone gave significant higher reserves and have been producing with more than 1 Bcf cumulative. The success story of those four wells leads the opportunity to propose new wells targeting proven depleted channels. Statistically, those channels have 6-8 meters of thickness, 14-16% of porosity, and 30-60 mD of permeability. A considerable amount of remaining potential in channel reservoirs was caused by commingled production strategy and relatively high flowing pressure in the past existing wells resulting in basket gas. Better production result than prognosis in depleted channel reservoirs is due to selective perforation strategy and lower back pressure due to lower production flowing pressure. Depleted channel reservoirs are still promising to be targeted for future wells candidate using more systematic approach. This paper endeavors to exhibit a systematical approach in converting undervalued potential of depleted channel reservoirs to compelling prospects as an incremental value creation process in a mature gas field.

Field, petrographical and geochemical characterization of a layered anorthosite sequence in the Upper Main Zone of the Bushveld Complex

A sequence of eight poikilitic anorthosite layers (labeled 1 to 8), within the Upper Main Zone in the eastern lobe of the Bushveld Complex, are exposed along a road-cut, 5.3 km northeast of the town of Apel, Limpopo Province. The anorthosite layers are meter-scale in thickness (0.4 to 10 m), have sharp contacts and are defined on the size and shape of pyroxene oikocrysts they contain. The anorthosite sequence is bounded by typical Main Zone gabbronorites. Euhedral, zoned primocrystic laths of plagioclase (An62.5-80.6; 0.2 to 4 mm long) are morphologically identical throughout the anorthosite sequence and define a moderate to strong foliation that is typically aligned parallel to the plane of layering. Interstitial clinopyroxene and orthopyroxene typically occur as large (0.8 to 80 cm) oikocrysts enclosing numerous partly rounded plagioclase chadacrysts. Rarely, orthopyroxene appears as subophitic crystals enclosing few and significantly smaller (0.08 to 0.4 mm), equant plagioclase inclusions. Detailed plagioclase and pyroxene mineral compositions for layers 2 to 5 show minimal variations within layers (0.1 to 2.3 mol% An and 0.7 mol% Mg#), whereas compositional breaks occur between layers (0.5 to 3.8 mol% An and 1.3 mol% Mg#). In layers 2 to 5, the An-content of plagioclase cores and the Mg# of both clinopyroxene and orthopyroxene crystals decrease by 2.5 mol%, 8.6 mol% and 13.0 mol% upwards, respectively. Bulk-rock incompatible trace element concentrations and patterns are similar for all analyzed anorthosite layers indicating that they are related to the same parental magma. However, bulk-rock major element oxides (e.g. Al2O3, TiO2, K2O) and atomic Mg# become more evolved upwards, consistent with magmatic differentiation. Based on the consistent plagioclase crystal morphologies and relatively constant chemistries within each anorthosite layer, we propose that each layer was formed by the intrusion of a plagioclase slurry. The upwards-evolving mineral chemistries, bulk-rock major element oxides and atomic Mg# suggests that each plagioclase slurry injection, that yielded an anorthosite layer, was derived from a slightly more fractionated parental magma prior to emplacement.

Efektivitas low light emitting diode sebagai lampu pengumpul ikan untuk perikanan bagan tancap

The effectiveness of the artificial lights on fishing activity with a fixed lift net is significant influences on the success of fishing operations. The used of color and intensity must be adjusted to the preferences, response and behavior of the target fish, due to the fish can be more quickly attracted and concentrated in the catchable area. The development of LED technology as an energy-saving lamp has a great opportunity to be applied as a fishing lamp for fixed lift net fisheries. The purpose of this study is to determine the effectiveness of low power LEDs as a fishing lamp based on fish behavioral response. The study was conducted on a research field laboratory that was built in the waters of the Banten Bay in July - August 2018. Test fish were collected from catches of the guiding barrier around the research vehicle. Data on response and behavior of fish to fluorescent lights, blue, green and white LEDs were recorded using 360 ° sonar and side imaging sonar. The results showed the green LEDs had better effectiveness in attracting, focusing and concentrating fish in the main zone than other types of lights. The fish gather more quickly, form groups and have a stable and consistent swimming pattern in the main lighting zone. Green LED is more appropriate to be used as a fishing lamp on fixed lift net fishing with an optimum intensity range of 4-20 μW cm².Keywords: Light, Intensity, Optimum, Response, BehaviorABSTRAKEfektivitas lampu yang digunakan pada proses penangkapan dengan bagan tancap sangat berpengaruh terhadap keberhasilan operasi penangkapan ikan. Intensitas dan warna yang digunakan harus disesuaikan dengan preferensi, respons dan tingkah laku ikan target sehingga ikan lebih cepat terkumpul dan terkonsentrasi pada catchable area. Perkembangan teknologi LED sebagai lampu hemat energi berpeluang besar digunakan sebagai fishing lamp untuk perikanan bagan tancap. Penelitian ini bertujuan untuk menentukan efektivitas low power LED sebagai lampu pemikat ikan berdasarkan aspek respons dan tingkah laku ikan. Penelitian dilakukan pada wahana penelitian yang dibangun di perairan Teluk Banten pada bulan Juli - Agustus 2018. Ikan uji diperoleh dari hasil tangkapan sero yang berada di sekitar wahana penelitian. Data respons dan tingkah laku ikan terhadap lampu neon, LED biru, hijau dan putih direkam menggunakan sonar 360° dan side imaging sonar. Hasil penelitian menunjukkan LED hijau memiliki efektivitas yang lebih baik dalam memikat, mengumpulkan dan mengkonsentrasikan ikan pada main zone dibandingkan jenis lampu lainnya. Ikan lebih cepat berkumpul, membentuk kelompok serta memiliki pola renang yang stabil dan konsistem di zona utama pencahayaan. LED hijau lebih tepat digunakan sebagai fishing lamp pada bagan tancap dibandingkan jenis lampu lainnya dengan intensitas optimum antara 4-20 μW/cm².Kata kunci: Cahaya, Intensitas, Optimum, Respons, Tingkah laku

Stability of a Petroleum-Like Hydrocarbon Mixture at Thermobaric Conditions That Correspond to Depths of 50 km

The commercial discovery of giant crude oil deposits at depths deeper than 10 km in various petroleum basins worldwide casts doubt on the validity of the theoretical calculations that have determined that the main zone of petroleum formation is at depths of 6–8 km (the ‘oil window’). However, the behavior of complex hydrocarbon systems at thermobaric conditions, which correspond to depths below 6–8 km, is poorly known. We experimentally investigated the thermal stability of a complex hydrocarbon system at the pressure-temperature conditions of Earth’s lower crust by means of Raman and Mössbauer spectroscopies. Our results demonstrated the chemical stability of the complex hydrocarbon system at thermobaric conditions corresponding to depths of 50 km, including the redox stability of the hydrocarbon system in a highly oxidative environment. The results of these experiments allowed us to revise the depth range in which petroleum deposits could occur.

Parental magma composition of the Main Zone of the Bushveld Complex: Evidence from in-situ LA-ICP-MS trace element analysis of silicate minerals in the cumulate rocks

<p>In-situ trace element analysis of cumulus minerals may provide a clue to the parental magma from which the minerals crystallized. However, this is hampered by effects of the trapped liquid shift (TLS). In the Main Zone (MZ) of the Bushveld Complex, the Ti content in plagioclase grains shows a clear increase from core to rim, whereas most other elements (e.g., rare earth elements (REEs), Zr, Hf, Pb) do not. This is different from the prominent intra-grain variation of all trace elements in silicate minerals in mafic dikes and smaller intrusion, which have a faster cooling rate. We suggest that crystal fractionation of trapped liquid occurred in the MZ of Bushveld and the TLS may have modified the original composition of the cumulus minerals for most trace elements except Ti during slow cooling. Quantitative model calculations suggest that the influence of the TLS depends on the bulk partition coefficient of the element. The effect on highly incompatible elements is clearly more prominent ­­than on moderately incompatible and compatible elements because of different concentration gradients between cores and rims of cumulate minerals. This is supported by the following observations in the MZ of Bushveld: 1) positive correlation between Cr, Ni and Mg# of clinopyroxene and orthopyroxene, 2) negative correlation between moderately incompatible elements (e.g., Mn and Sc in clinopyroxene and orthopyroxene, Sr, Ba, Eu in plagioclase), but 3) poor correlation between highly incompatible elements and Mg# of clinopyroxene and orthopyroxene or An# of plagioclase. Modeling suggests that the extent of the TLS for a trace element is also dependent on the initial fraction of the primary trapped liquid, with strong TLS occurring if the primary trapped liquid fraction is high. This is supported by the positive correlation between highly incompatible trace element abundances in cumulus minerals and whole-rock Zr contents.</p><p>We have calculated the composition of the parental magma of the MZ of the Bushveld Complex. The compatible and moderately incompatible element contents of the calculated parental liquid are generally similar to those of the B3 marginal rocks, but different from the B1 and B2 marginal rocks. For the highly incompatible elements, we suggest that the use of the sample with the lowest whole-rock Zr content and the least degree of TLS is the best approach to obtain the parental magma composition. Based on calculation, we propose that a B3 type liquid is the most likely parental magma to the MZ of the Bushveld Complex.</p>