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Cretaceous
_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 214066, โSeismic Reprocessing Leads to New BreakthroughsโA Successful Case in the ASH Field, AG Basin in Egypt,โ by Mohamed Elokr and Ahmed Lotfy, Kuwait Energy Egypt, and Wei Xing, United Energy Group, et al. The paper has not been peer reviewed. _ The ASH oil field is in the eastern portion of the AG Basin in Egypt. The Lower Cretaceous Alam El Bueib is the main oil-producing formation. Because of the high heterogeneity of the Abu Roash succession, in addition to the influence of thick limestone of the Upper Cretaceous and the influence of multiple complex faults, the quality of seismic data is very poor, requiring seismic reprocessing. Two key techniques were used to achieve the goal: New vertical seismic profile (VSP) well data were acquired to adjust the velocity model, and common reflection angle migration (CRAM) prestack depth migration (PSDM) was used for reprocessing. Introduction The ASH field produces oil from the Aptian Lower Cretaceous reservoir. The ASH structure is interpreted as an elongated east-northeast/west-southwest anticline with intensive breaching on the downthrown side of northwest/southeast to west-northwest/east-southeast-oriented normal faults with obvious signature of synsedimentary activities. The entire area was subject to a series of tectonic events affecting the Western Desert, which led to a complex fault regime clearly recognized in the ASH structure by a series of horizontal displacement across the northwest/southeast faults. Strike/slip to oblique-slip faults also are observed from thicknesses of the cretaceous formations, creating significant difficulty in fault definition. The 3D seismic data acquired in 2007 suffered from losing amplitude of the Lower Cretaceous and deep Jurassic reflectors because of the complex structure. The strong carbonate markers disappear north of the field, where high, dense fault intersection is present closing from the main bounding fault. Loss of seismic amplitude could have severe effects on of the future economics of the field. The seismic survey was reprocessed two times without significant enhancement of the fault imaging. PSDM was run without velocity control, resulting in an uncertain velocity model with inaccurate fault imaging and a mismatching between actual and prognosed depths of the drilled wells of greater than 50 m. This contradiction in reservoir mapping meant that the northern portion of the field remained unexplored. Acquiring VSP in the recently drilled well encouraged reprocessing of the 3D seismic survey using well velocity as a control point in adjusting the seismic velocity model, and application of CRAM technology to improve fault imaging and appraise the uncertain area of the ASH field. CRAM Methodology CRAM was developed as a type of beam migration. Asymptotic ray tracing is performed, assuming that one-way diffraction rays from the subsurface image point to the surface sources and receivers. The takeoff angles from the image point are measured around a given local normal to a background reflection surface for each source ray and receiver ray. A system of source and receiver ray pairs is formed, and the recorded seismic data can be mapped into a local angle domain based on the reflection angles at the subsurface image points.โโโโ
- Africa > Middle East > Egypt > Western Desert (1.00)
- North America > United States > North Dakota > Bowman County (0.97)
- Africa > Middle East > Egypt > Western Desert > Greater Western Dester Basin > Abu Gharadig Basin > Abu Sennan Concession > ASH Field (0.99)
- Africa > Middle East > Egypt > Western Desert > Bahariya Formation (0.99)
Challenges Related to Oyster Floatstones in Vaca Muerta Development. Visualization on PSTM, PSDM and Diffraction Imaging
Roth, Rocรญo L. (YPF S. A.) | รlvarez, Pablo F. (YPF S. A.) | Tarrรฉs, Gustavo (YPF S. A.) | Jaimes, Vladimir Merchan (YPF S. A.) | Licitra, Diego T. (YPF S. A.) | Goรฑi, Gabriela (YPF S. A.)
Abstract The block under analysis is located at the south of Neuquรฉn basin (Argentina), where Vaca Muerta formation (VMF) produces gas from organic rich black shales. Quintuco Fm., the overlying unit, is composed by limestones and mudstones deposited in shallow waters and presents carbonate build-ups interpreted as oyster floatstone. During drilling, it was observed that if well paths cross these carbonates build-ups, important mud losses and/or gas kicks may occur. Therefore, the objective of this work is to establish the distribution of these bodies to avoid them when wells are drilled and reduce the associated risk. Additionally, these geobodies cause some issues in seismic data affecting the image below them and some procedures like PSDM. Based on seismic analysis like RMS amplitude and diffraction imaging, electrical logs interpretation combined with outcrops analogs, a new geological view was proposed, allowing the adjustment of directional plans and reducing drilling risks. Introduction The study area is in the shale gas sector of Vaca Muerta Fm. located in the Neuquรฉn basin, Argentina, within the morphostructural zone of the Embayment (Figure 1), described by Cristallini et al. (2009) and Pรกngaro et al. (2011). The Quintuco-Vaca Muerta system model consist of a mixed siliciclastic-carbonatic ramp, with a SE-NW orientation, where organic rich black shales (Vaca Muerta) are mostly located in the bottomset with an agradational setting, interpreted as distal platform and center basin deposits. While limestone facies (Quintuco) correspond to foreset and topset mainly with a progradational setting and represents the proximal platform deposits (Figure 2). The present analysis includes two blocks in the gas window, where VMF is developed with horizontal wells of variable lateral length. The main objectives or landing zones correspond to bottomset facies, with the highest organic rich content (TOC), yielding the best productive benches in the area. However, in the overlying level called Berriasian, within an interval of 200m approximately, seismic amplitude anomalies were observed and interpreted as carbonate build-ups. A schematic diagram in Figure 2 shows the proposed paleoenvironmental model for the Berriasian, where the genesis of these bodies is associated with a low energy environment (Pรกngaro et al., 2005).
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Vaca Muerta Shale Formation (0.99)
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Quintuco Formation (0.99)
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Vaca Muerta Field > Vaca Muerta Shale Formation (0.98)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Abstract Oil and gas occur in basement reservoirs in many parts of the world. The reserves of basement fields are as small as one or two million barrels of oil or gas-equivalent to over 2.3 billion barrels of oil as in China's Reniqiu oil field. Exploration for oil and gas in basement has been remarkably successful in the past decade with important discoveries in basement in China, Indonesia, United Kingdom, Norway, Chad, and Argentina. To successfully develop basement oil and gas fields and to avoid costly mistakes, all available geological, geophysical and reservoir engineering must be closely studied. Also, it is very important to study analogues of basement oil and gas fields worldwide to understand why some fields are very successful and others turn out to be failures. The author has followed this subject closely for over forty years, since being involved in 1982 with the development of the Beruk Northeast basement oil pool in Indonesia. He has also been involved with evaluating basement oil discoveries in Angola, Uganda, and the interior of the USA. He hereby shares his knowledge and experience. This paper provides a technical review of select fields in Asia, Africa, and the Americas. Also reviewed are "best practices" for exploring and developing basement fields. Best practices include drilling at least 100 meters through the top of the basement. Exploration and development well locations must be based on state-of-the-art 3D seismic data. Depending on the orientation of the dominant fractures, all wells must be drilled almost perpendicular to the fractures. The success of optimally placed development wells has been documented in prolific fields such as the Bach Ho (White Tiger) and CNV oil fields in Vietnam and the giant Suban gas field in South Sumatra, Indonesia. Although this paper reviews mostly "success stories", there are also failures, since basement reservoirs can be very complicated and unpredictable. Accordingly, two basement fields which proved to be economic failures, Dai Hung (Big Bear) in Vietnam and Beruk Northeast in Indonesia, are also reviewed. Reviewing such situations is important due to the saying, "We learn from our successes, but we also learn from our failures". The world's largest oil and gas basement fields occur within basement which is heavily naturally fractured. The opinion of this author is that the best rock types are fractured quartzites or granites, since they are brittle and thus fracture optimally. Weathered granitic basement can also be an excellent reservoir, as in the giant Augila-Naafora oil field in Libya. Fractured granitic gneisses are moderately good basement reservoirs whereas phyllites, schists and slates are the least preferrable basement reservoirs. My ongoing global review of basement oil and gas fields indicates that the best place to explore for oil and gas in basement is beneath oil or gas fields which produce from the sediments overlying basement. Prime examples are the Indonesia's Suban gas field as wells as the La Paz and Mara oil fields in Venezuela and the Octogono oil field in Argentina.
- North America > United States > Texas (0.93)
- South America > Venezuela > Zulia (0.88)
- Asia > Indonesia > Sumatra > South Sumatra (0.69)
- North America > United States > California > Los Angeles County (0.46)
- Phanerozoic > Paleozoic (1.00)
- Phanerozoic > Cenozoic (0.93)
- Phanerozoic > Mesozoic > Cretaceous (0.47)
- Geology > Rock Type > Sedimentary Rock (1.00)
- Geology > Rock Type > Metamorphic Rock (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (1.00)
- Geology > Rock Type > Igneous Rock (0.71)
- 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)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Abstract The study area is located in Tupi field in Santos Basin. It is one of the largest Brazilian maritime basins. They were formed during the Neocomian period as a result of the process of separation of the supercontinent Gondwana. Detailed description work was carried out on plug samples from the five wells in the Tupi oil field to understand carbonate facies and their distribution better. The samples were obtained from the Exploration and Production Database (BDEP/ANP). The facies analysis followed the classification standards proposed by Gomes et al. (2020). The results showed the diversity of facies, with significant variability along the depth of each well, which are related to different depositional environments. In situ, facies with a higher proportion of mud indicate conditions with lower flow energy. At the same time, a greater abundance of spherulites and shrubs may signal shallow water environments, providing carbonate precipitation for forming these structures. Reworked facies indicate environmental conditions with high flow energy, wave and wind action. Introduction The study area is located in Tupi field in Santos Basin, in the southeastern part of the Brazilian continental margin, occupying an area of nearly 352,000 km and water depths of up to 3,000 m. It is one of the largest maritime basins in Brazil, and, being situated approximately 230 km from the Brazilian coast, it extends along the coasts of the states of Rio de Janeiro, Sรฃo Paulo, Paranรก and Santa Catarina (Moreira et al., 2007) (Fig. 1). The formation process of Brazilian marginal basins had its origins during the rupture of the Gondwana Supercontinent in the Neocomian period, approximately 135 Ma. ago, and the supercontinent rifting resulted in the separation of the African and South American continents and the opening of the South Atlantic Ocean. During the evolution of Brazilian marginal basins, large lacustrine carbonate deposits were covered by an extensive evaporite layer that served as a trap for significant quantities of hydrocarbons, known as the Pre-salt section. The carbonate deposits received worldwide attention and became relevant due to the economic discovery of this considerable accumulation of oil in the Santos Basin and the confirmation of the exploratory viability of these new oil reservoirs.
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean (1.00)
- South America > Brazil > Brazil > South Atlantic Ocean (1.00)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock (1.00)
- Geology > Structural Geology > Tectonics > Salt Tectonics (0.75)
- Geology > Sedimentary Geology > Depositional Environment > Continental Environment > Lacustrine Environment (0.58)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Santos Basin > Block BM-S-11 > Tupi Field > Lula Formation (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Santos Basin > Block BM-S-11 > Tupi Field > Guaratiba Formation (0.99)
- South America > Brazil > Rio de Janeiro > South Atlantic Ocean > Santos Basin > Block BM-S-11 > Tupi Field > Cernambi Formation (0.99)
- (5 more...)
First Results in the Evaluation of Unconventional Reservoirs of the Anticline Aguada Bandera Formation on the West Flank, Golfo San Jorge Basin
Guerra, Germรกn Andrรฉs (YPF S.A., Buenos Aires, Argentina) | Gonzalez, Laura (YPF S.A., Buenos Aires, Argentina) | Palafox, Gastรณn Iovine (YPF S.A., Buenos Aires, Argentina) | Brisson, Ignacio (YPF S.A., Buenos Aires, Argentina)
Abstract The San Jorge Gulf Basin is located in the central portion of Patagonia, Argentina. It has more than 100 years of oil exploration and development. This contribution aims to show the first results of evaluating unconventional reservoirs of the Pozo Anticline Aguada Bandera Formation (PAAB Fm.) in Cerro Piedra oilfield, Santa Cruz province. During the middle Jurassic to Early Cretaceous, an extensional period led to the initial opening of the San Jorge Gulf Basin generating a series of deep isolated basins, called informally "Neocomian depocenters". These were filled first with sedimentary volcanic complex and equivalents after that lacustrine and deltaic sediments in the eastern sector of the San Jorge Gulf Basin while marine and mixed lacustrine environments prevailed in the western region. The Neocomian cycle started with the filling of these halfgrabens with shaly conglomerates and shales of the PAAB Fm. and equivalents that constitute the late synrift sequence. During the sag stage, these depocenters were filled up with sandstones of the Cerro Guadal Formation. In the study area, the shale rock has type I/II kerogen. The total organic Carbon (TOC) varies between 2 and 4%, with organic rich sections that can be around 200 to more than 1000 meters thick. The maturity ranges from oil to gas depending on the position and depth of grabens. An exploratory well was drill in the oil window, and hydraulic stimulated during completion in PAAB Fm. shales at 2400 meters below sea level. From the DFIT data, an overpressure of 30% was verified and the fracture gradient was 0.87 psi/ft. The post-frac test showed 43ยฐ API oil and became the first sample of PAAB Fm. in source fluid in the basin. These encouraging results reinforce the potential of this lacustrine shale to continue the exploration as shale resource system, which was previously envisaged on its excellent geochemical characteristics, adequate thickness and its more than 2000 km areal extension. Introduction The Golfo San Jorge Basin (GSJB) is located in central Patagonia between latitudes 44ยฐ and 47ยฐS, covering a surface of approximately 180,000 km. This intracratonic basin is mostly extensional and extends roughly in an east-west direction from the Andean Belt to the Atlantic Ocean. It is bordered to the north by the Caรฑadon Asfalto Basin and to the south by the Deseado region. The basin is divided into five different regions according to the present structural style. The North Flank, South Flank, and Basin Center are characterized by normal faults with E-W strike, where each region is dominated by dipping directions basinward (Figure 1) (Figari et al., 1999; Sylwan et al., 2011). The San Bernardo Fold Belt (SBFB) and Western Flank are identified by positive tectonic inversion features. The former characterized by the domain of contractional structures N-S oriented and the latter by structures with NW-SE strikes with a lower degree of inversion (Fitzgerald et al., 1990; Figari et al., 1996, 1999; Sylwan et al., 2011). The study area, Cerro Piedra Cerro Cuadrado oilfield, is in the boundary between SBFB and the Western Flank.
- Geology > Structural Geology > Tectonics (1.00)
- Geology > Sedimentary Geology > Depositional Environment (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- South America > Argentina > Santa Cruz > Golfo San Jorge Basin > Cerro Piedra Field (0.99)
- South America > Argentina > Patagonia > Golfo San Jorge Basin (0.99)
- South America > Argentina > Tierra del Fuego > Magallanes Basin > Magallanes Basin > Rรญo Mayo Embayment > Coihaique Group > Katterfeld Formation (0.94)
- (5 more...)
Abstract The Vaca Muerta Formation has been extensively studied as an unconventional play and is currently in a development stage at the center of the Neuquรฉn basin. However, some areas of the basin remain unexplored due to different kinds of geological risks. This contribution centers on the southern part of Mendoza Province and shows the studies carried out to evaluate the source rock as a potential shale reservoir and mitigate uncertainties associated with these risks. Structural and isopach maps were made using 2D and 3D seismic data. Petrophysical evaluation based on nearby well logs identified interesting intervals. Geochemical data collection yielded encouraging results for this source rock, including rich organic content (>2% TOC) and thermal maturity values showing early to mature oil generation window. Additionally, a geomechanical model was made and recalibrated using a DFIT from a close-by well. As a result of all these studies, some exploratory proposals were defined to assess the Vaca Muerta Formation's potential as an unconventional play in a frontier area. In 2023, a vertical pilot and two horizontal wells were drilled, validating the expected parameters and even exceeding them. Regional interpretation carried out gave rise to the extension of the potential exploration borders of Vaca Muerta Formation, revaluing a large area on the northern margin of the Colorado River. Introduction This study focuses on evaluating the potential of the Vaca Muerta Formation as an unconventional shale oil play. The aim was to expand the exploratory boundaries for this unit towards the southern region of Mendoza Province. Vaca Muerta Formation (Weaver, 1931, emend. Leanza 1972) serves as the primary source rock in Neuquรฉn Basin. It is characterized by its extensive areal distribution and represents the distal facies of a series of carbonate and/or mixed systems that were established in the basin between the early Tithonian and early Valanginian stages (Legarreta and Uliana, 1991; Legarreta et al., 1993). This unit ranks among the world's largest sources of unconventional hydrocarbons, ranking Argentina as the second-largest global resource holder for unconventional gas and fourth-largest for unconventional oil (EIA, 2013).
- South America > Argentina > Patagonia Region (1.00)
- South America > Argentina > Neuquรฉn Province > Neuquรฉn (1.00)
- Phanerozoic > Mesozoic > Jurassic > Upper Jurassic > Tithonian (0.54)
- Phanerozoic > Mesozoic > Cretaceous > Lower Cretaceous > Valanginian (0.54)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.76)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.56)
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (0.87)
- Geophysics > Seismic Surveying > Seismic Interpretation (0.68)
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > North America Government > United States Government (0.56)
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Vaca Muerta Shale Formation (0.99)
- South America > Argentina > Mendoza > Neuquen Basin (0.99)
- South America > Argentina > Patagonia > Neuquรฉn > Neuquen Basin > Vaca Muerta Field > Vaca Muerta Shale Formation (0.98)
- Oceania > Australia > Victoria > Bass Strait > Gippsland Basin (0.89)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Shale oil (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- (4 more...)
Assessment of Makhul Unconventional Reservoir in Kuwait: Play to Pilot Locations
Al-Ali, Salem (Kuwait Oil Company) | Al-Ibrahim, Afrah (Kuwait Oil Company) | Al-Haggan, Hamad (Kuwait Oil Company) | Al-Hamad, Abdullah (Kuwait Oil Company) | Prakoso, Anton (Kuwait Oil Company) | Al-Wadi, Meshal (Kuwait Oil Company)
Abstract Makhul Formation comprises a transgressive sequence of organic rich argillaceous limestones, calcareous mudstones and dark euxinic bituminous rich claystones. Formation is divisible into three parts - the lower part (Makhul organic rich mudstone) is made up of organic rich lime mudstone while the middle part (Makhul transition) consists of Organic rich Mudstone and limestone intercalations and the uppermost part (Makhul tight limestone) is characterized by tight lime mudstone. Study focuses on play fairway assessment Sweet spot mapping and identification of exploratory drilling locations for Makhul Unconventional reservoir.
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
Geological Characteristics of Abiotic Natural Gas Reservoirs and Helium Enrichment Factors of the Songliao Basin
Yang, Yiqing (PetroChina Research Institute of Petroleum Exploration and Development) | Tao, Shizhen (PetroChina Research Institute of Petroleum Exploration and Development) | Chen, Yue (PetroChina Research Institute of Petroleum Exploration and Development) | Yang, Liang (Daqing Oilfield Exploration and Development Research Institute) | Fu, Li (Daqing Oilfield Exploration and Development Research Institute) | Wang, Lei (Daqing Oilfield Exploration and Development Research Institute)
Abstract The unique post-arc mantle uplift and thin crustal extensional slip regional tectonic background of the Songliao Basin, China, and the Cretaceous-Cenozoic volcanic magmatic activities in the rift basin have led to the widespread development of abiotic gas reservoirs. These reservoirs are mainly located in the vicinity of "net-like" deep and large fractures developed in the crust with strong volcanic activity. Historically, volcanic eruptions were frequent in Songliao Basin, since the eruption of the Yingcheng Formation, volcanic activities happened through the late-stage deposition of Quantou Formation, and till the end of the Late Cretaceous and Quaternary. Hence, in the later burial, the pressure decrease, or temperature increase can lead to the slow degassing of the large amount of mantle-sourced CO2 adsorbed or free in the volcanic rocks of the Yingcheng Formation. Meanwhile, under the interaction of abiotic deep hydrothermal fluids, various reservoirs with extremely developed dissolution pore space are formed, and the storage conditions are refined. With the shallow burial of the Moho surface in the Songliao basin, about 29-34 km, the basin heat flow value is high, and the total average value of heat flow is 78.9 mW/m(Hao et al., 2023). So, with the effective communication of sub-fractures at all levels, the mantle-sourced CO2 can be transported along the deep large fractures to and later accumulate late-stage in the reservoirs in the clastic trap from the Denglouku to the Quantou Formation. Irwin and Barnes believed that the global CO2 distribution characteristics are correlated with the background of tectonic activity. They suggested that CO2 with metamorphic origin is mostly developed in the compressed tectonic structure, while mantle-source magmatic gas is mainly formed in the extensional tectonic zone. The Songliao Basin is consistent with this feature. In the Songliao Basin, carbonate rocks are less distributed, and only some gas reservoirs with tuff distribution were observed and no high CO2 was found. Such as in the Changling, Dehui, Xujiaweizi, and Gulong rifts, some gas reservoirs have abiotic CO2 >90% (Liu et al., 2016), and the high CO2 content of these gas reservoirs has obvious characteristics of mantle source inorganic genesis. However, there are also some hydrocarbon reservoirs with CO2 content <20%, which are considered inorganic, organic, or mixed genesis. Helium has both crustal sources and mantle sources. Crustal helium released by U and Th decay can be transported by subsurface fluids to degas when meeting with other gases and accumulate along with hydrocarbon or CO2. The mantle helium can be proportionally input to the reservoir with the mantle-sourced CO2 since they can share the fluid transportation channel. Hence, the distribution of mantle-sourced CO2 affects the distribution of helium to a certain extent. The distribution of crustal helium is generally considered to be related to the distribution of basement granites, but the distribution of helium in the same tectonic unit of Songliao Basin appears to be more diffused, mainly due to the small molecular weight of helium, which is more demanding than hydrocarbons and CO2 in terms of the trap conditions. Also, the extensive development of "net-like" multi-stage fractures in Songliao Basin, such as Lithospheric fractures, crustal fractures, and basement fractures are widely developed. These fractures and the characteristics of the Songliao Basin as a "hot basin" together determine the distribution of helium.
- Geology > Geological Subdiscipline > Volcanology (1.00)
- Geology > Structural Geology > Tectonics > Plate Tectonics (0.90)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock (0.90)
- Geology > Structural Geology > Tectonics > Extensional Tectonics (0.67)
- Asia > China > Northeast China > Songliao Basin > Yingcheng Formation (0.99)
- Asia > China > Northeast China > Songliao Basin > Quantou Formation (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Qingshen Field (0.99)
- (3 more...)
Description and Analysis of the First Two Vertical Pilot Wells Completions to the Palermo Aike Shale: A Highly Promising Unconventional Reservoir in Austral Basin, Argentina
Melendo, F. (CGC, Rรญo Gallegos, Argentina) | Gargiulo, C. (CGC, Capital Federal, Argentina) | Garcia, N. (Geomechanical & Frac Consultant, NOTIO, Mendoza, Argentina) | Jait, D. (Exploration & Development, CGC, Capital Federal, Argentina)
Abstract The Austral-Magallanes basin, located in the southern part of Argentina and Chile, has a long history of oil and gas activity from conventional and tight reservoir rocks. Compaรฑรญa General de Combustibles (CGC), the main operator in the Argentina onshore area, started in 2017 a detailed analysis of the unconventional opportunities associated to Palermo Aike Inferior Formation, the main source rock of the basin, to enhance the basin and country energy opportunities. This work will present the full workflow associated with the completion and well testing of these first two wells targeted to characterize and test the production potential and reservoir fluids of part of the Palermo Aike shale, in two different maturity range and thickness areas 40 km apart. Starting by describing the main geological take aways used to plan the well completions. Following with the summary of the completion and well testing program prepared to achieve the objectives of the project. Finally, a review of all the actions and decisions taken during lab testing, DFIT planning, execution and interpretation, geomechanical characterization, frac job design and execution, frac height measurements and well testing operation. The main lessons learned from this promising unconventional reservoir are shared, together with some of the questions still pending to be answered with a few options to address them. Promising initial results were obtained, the frackabilty of the Palermo Aike was proved. Excellent overpressure was registered, and continuous oil flow was obtained. Initial results support the next step in the delineation of the play. Horizontal multifracture well will be drilled and complete by 4Q of year 2023. Introduction Austral (Magallanes) Basin is located in the southern end of continental South America and extends towards Tierra del Fuego Island and offshore vicinity. The lower member of the Palermo Aike Formation is the main source rock of the basin and it has been recognized as the second potential shale play resource in Argentina and third in South America (EIA, 2015).
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.62)
- South America > Brazil > Campos Basin > Campos Field (0.99)
- South America > Argentina > Tierra del Fuego > Magallanes Basin > South-central > Springhill Formation (0.99)
- North America > United States > Oklahoma > Anadarko Basin > Sooner Trend Anadarko Canadian and Kingfisher Play (STACK) > Sooner Trend Anadarko Canadian and Kingfisher Play (STACK) (0.99)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Drillstem/well testing (1.00)
- Management > Energy Economics > Unconventional resource economics (1.00)
A Unique Methodology and Successful Implementation While Testing Exploratory Well in Bahrah Field with Several Challenges: A Case Study in North Kuwait
Alotaibi, F. Z. (Kuwait Oil Company, Ahmadi, Kuwait) | Al-Ibrahim, A. (Kuwait Oil Company, Ahmadi, Kuwait) | Ibrahim, A. (Kuwait Oil Company, Ahmadi, Kuwait) | Binsafar, A. (Kuwait Oil Company, Ahmadi, Kuwait) | Alkhulaifi, O. (Kuwait Oil Company, Ahmadi, Kuwait)
Abstract Objectives/Scope This paper presents a unique successful application and implementation of testing procedures in an exploratory cretaceous well in Bahrah field (North Kuwait). Used to evaluate productivity and characteristics of a reservoir and clearly understand the reservoir's potential, which helps in reducing the risks related to developing the field for a long-term with sustainable production, and selecting the optimum completion and artificial lift method. Methods, Procedures, Process The exploratory vertical well BH-X drilled to explore the hydrocarbon potential within the Northern Area of the Bahrah field targeting cretaceous Sandstone formation, with a total drilling depth 10,780 ft. Open-hole logs and collected WL open-hole fluid sample post drilling proved the oil bearing in the sandstone formation. The cement bond evaluation behind slim casing liner showed some doubt in quality in particularly cement image of ultrasonic tool. Decision was taken to proceed with testing without cement remediation, and perform a DST with down-hole real-time pressure gauges. The Formation interval was perforated using dynamic underbalance casing guns post displacing the completion fluid in hole OBM with filtrated brine. The Nitrogen (N2) lifting through Coiled tubing (CT) was used for well activation and to evaluate the well productivity on rig since the well ceased to flow naturally. Since these pressure events and analysis are crucial in making decisions in a low cost environment, It was decided to retrieve the downhole pressure data for preliminary Pressure Transient Analysis (PTA), which indicated that the formation skin was positive. Therefore, acid wash was performed to the sensitive sandstone formation to enhance the production rate. Results, Observations, Conclusions However, the results post the acid wash treatment showed increment in water cut. RIH with Water-Flow Log (WFL) to check the water source and identified channels behind pipe was challenging due to unavailability of E-coiled tubing. Thus, a unique solution was used to achieve a drawdown and dynamic condition while recording conventional WFL against the testing zone by using N2 and utilizing the DST tools functions. WFL results indicated the source of water behind casing above the test interval. Therefore, a cement squeeze job was performed and cement bond log was recorded again post the remedial job, which confirmed a good improvement in cement bond. The targeted interval was re-perforated utilizing dynamic underbalance perforation with STIM guns, the well was activated by CT using N2 lifting and showed clear improvement in production with zero water cut. Novel/Additive Information Overall, a unique methodology while using real time data has delivered better decision making and operational capabilities during rig and testing operations, which assists in reducing well testing operations cost and time.
- Asia > Middle East > Kuwait > Jahra Governorate > Arabian Basin > Widyan Basin > Bahrah Field > Marrat Formation (0.99)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Zubair Field > Zubair Formation (0.98)
- Asia > Middle East > Iraq > Basra Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Zubair Field > Mishrif Formation (0.98)