Three cases of structural-stratigraphic accumulations in the foredeep zone of the Oriente Basin have been analyzed.The target reservoirs are U and M1 sections of Napo Fm.in the Basin.Seismic amplitude maps are used fo...Three cases of structural-stratigraphic accumulations in the foredeep zone of the Oriente Basin have been analyzed.The target reservoirs are U and M1 sections of Napo Fm.in the Basin.Seismic amplitude maps are used for sand distribution pattern,and wells interpretation and correlations are applied for fluid distribution and reservoir continuity.These cases show that their oil distribution areas are significantly larger than their structure closures and thus should be structural-stratigraphic traps.But only in one case,lateral stratigraphic/lithological seals can be clearly observed.In the other two,the lateral seals are apparently discontinuous and cannot provide a complete barrier at the up-dip of the structures.Possible factors for the formation of those untypical structural-stratigraphic accumulations are studied,such as formation water flow and water head variations,basin and field structure evolution patterns,oil generation and charging history etc.An integrated mechanism is proposed in this study,where three factors may have acted together.1)Slow long distance oil migration in LU and M1 reservoirs,due to their lateral discontinuity in the foredeep of the basin.This is supported by the distal estuarine and prodelta depositional environment suggested by previous sedimentological studies.2)Ongoing secondary oil migration from south to north,caused by southward plunging and destruction of proto accumulations in the southern and middle part of the basin.This structure deformation is in turn caused by differential subsidence between the southern and northern part of the basin.3)Additional oil supplied from the southern kitchen.The southern source kitchen is still in the oil window and providing pulses of oil charge since the Oligocene.If this mechanism is valid,it would imply that in the southern and northern transition zone of the basin,similar untypical traps should also exist.The area of southern extension of the two untypical accumulation is over 50 km2,while within the basin,the transition zone of differential basin subsidence with distal and thus discontinuous LU and M1 reservoirs covers an area over 2000 km2.These findings suggest a new and potentially extensive play concept with significant exploration potential in the Oriente Basin.展开更多
The petroleum geological features of hydrocarbon source rocks in the Oriente Basin in Ecuador are studied in detail to determine the potential of shale gas resources in the basin. The favorable shale gas layer in the ...The petroleum geological features of hydrocarbon source rocks in the Oriente Basin in Ecuador are studied in detail to determine the potential of shale gas resources in the basin. The favorable shale gas layer in the vertical direction is optimized by combining logging identification and comprehensive geological analysis. The thickness in this layer is obtained by logging interpretation in the basin. The favorable shale gas accumulation area is selected by referring to thickness and depth data. Furthermore, the shale gas resource amount of the layer in the favorable area is calculated using the analogy method. Results show that among the five potential hydrocarbon source rocks, the lower Napo Formation is the most likely shale gas layer. The west and northwest zones, which are in the deep-sea slope and shelf sedimentary environments, respectively, are the favorable areas for shale gas accumulation. The favorable sedimentary environment formed thick black shale that is rich in organic matter. The black shale generated hydrocarbon, which migrated laterally to the eastern shallow water shelf to form numerous oil fields. The result of the shale gas resource in the two favorable areas,as calculated by the analogy method, is 55,500×10;m;. This finding shows the high exploration and development potential of shale gas in the basin.展开更多
Exploration and development experience show that there is obvious oil gravity difference between the southern part and northern part of the ＂M1＂reservoir in the Fanny oil field in the slope of the Oriente Basin, Ecu...Exploration and development experience show that there is obvious oil gravity difference between the southern part and northern part of the ＂M1＂reservoir in the Fanny oil field in the slope of the Oriente Basin, Ecuador. The American Petroleum Institute Gravity （API） values of oils in the northern part are higher than the one in the southern part of the Fanny oil field, with the values of 20° and 10.0°-13.0°, respectively. So the primary purpose of this study was to analyze the heavy oil characteristics of biodegradation and the oil-oil correlation according to the biomarker data and the δ^13C signature of oil samples from T block. The results of the hydrocarbon gas chromatography fingermark and the inversion attribute characteristics indicated that there are fluid compartments between the ＂M1＂ reservoir of Fanny south. Finally, the models of oil-gas accumulation under the control of multiple-activities of complicated fault systems, as well as the origin of heavy oil, are contended. The early stage oils from the western part of the basin were biodegraded heavily in varying degrees in the whole basin, and the later stage oils were derived from the southern part in a large scale and were mature and lighter. Generally, oil mixing is the primary control of net oil properties, such as API gravity in Oriente Basin. We therefore predicted that the API gravity variation of oil pools radically depends on the injection amount of the later stage oil. Because of the shale barrier in the ＂M1＂reservoir of Fanny south, the later stage hydrocarbon could not pass through and contribute to increase the oil API value.展开更多
The exploitation of a thin-layered reservoir with thickness less than 5 m(16 ft)needs to rely upon sedimentary facies analysis,due to the low resolution of seismic data and sparse well data.However,the ambiguity of fa...The exploitation of a thin-layered reservoir with thickness less than 5 m(16 ft)needs to rely upon sedimentary facies analysis,due to the low resolution of seismic data and sparse well data.However,the ambiguity of facies interpretation creates uncertainty in facies and reservoir mapping.The study aims to better define facies distribution,predict sand-body architecture,and consequently reduce risks in planning development wells,by integrating production data(dynamic)with conceptual geological models(static).An example is shown from the M1 Member of the Napo Formation in the B and G Oilfields(Block J),Oriente Basin,Ecuador.The M1 reservoir is a thin-layered sandstone reservoir below seismic resolution.Core and well-log facies interpretation indicates depositional facies of a tidedominated estuary.Production data during the water injection phase of field development can delineate the detailed geometry of the sand bodies.The injector-producer rate responses can determine the connectivity of sand bodies.Well performance during primary recovery can capture the scale of single reservoirs because the initial production rates and the cumulative oil production of individual wells are generally proportional to the size of sand bodies.A facies model was thereby generated.Two step-out wells were planned using this model and drilled successfully.The results demonstrate that the integration of dynamic and static data is critical to understanding reservoir facies distribution.展开更多
基金funded by the special project of the Department of Science and Technology,Sinopec(P23180).
文摘Three cases of structural-stratigraphic accumulations in the foredeep zone of the Oriente Basin have been analyzed.The target reservoirs are U and M1 sections of Napo Fm.in the Basin.Seismic amplitude maps are used for sand distribution pattern,and wells interpretation and correlations are applied for fluid distribution and reservoir continuity.These cases show that their oil distribution areas are significantly larger than their structure closures and thus should be structural-stratigraphic traps.But only in one case,lateral stratigraphic/lithological seals can be clearly observed.In the other two,the lateral seals are apparently discontinuous and cannot provide a complete barrier at the up-dip of the structures.Possible factors for the formation of those untypical structural-stratigraphic accumulations are studied,such as formation water flow and water head variations,basin and field structure evolution patterns,oil generation and charging history etc.An integrated mechanism is proposed in this study,where three factors may have acted together.1)Slow long distance oil migration in LU and M1 reservoirs,due to their lateral discontinuity in the foredeep of the basin.This is supported by the distal estuarine and prodelta depositional environment suggested by previous sedimentological studies.2)Ongoing secondary oil migration from south to north,caused by southward plunging and destruction of proto accumulations in the southern and middle part of the basin.This structure deformation is in turn caused by differential subsidence between the southern and northern part of the basin.3)Additional oil supplied from the southern kitchen.The southern source kitchen is still in the oil window and providing pulses of oil charge since the Oligocene.If this mechanism is valid,it would imply that in the southern and northern transition zone of the basin,similar untypical traps should also exist.The area of southern extension of the two untypical accumulation is over 50 km2,while within the basin,the transition zone of differential basin subsidence with distal and thus discontinuous LU and M1 reservoirs covers an area over 2000 km2.These findings suggest a new and potentially extensive play concept with significant exploration potential in the Oriente Basin.
文摘The petroleum geological features of hydrocarbon source rocks in the Oriente Basin in Ecuador are studied in detail to determine the potential of shale gas resources in the basin. The favorable shale gas layer in the vertical direction is optimized by combining logging identification and comprehensive geological analysis. The thickness in this layer is obtained by logging interpretation in the basin. The favorable shale gas accumulation area is selected by referring to thickness and depth data. Furthermore, the shale gas resource amount of the layer in the favorable area is calculated using the analogy method. Results show that among the five potential hydrocarbon source rocks, the lower Napo Formation is the most likely shale gas layer. The west and northwest zones, which are in the deep-sea slope and shelf sedimentary environments, respectively, are the favorable areas for shale gas accumulation. The favorable sedimentary environment formed thick black shale that is rich in organic matter. The black shale generated hydrocarbon, which migrated laterally to the eastern shallow water shelf to form numerous oil fields. The result of the shale gas resource in the two favorable areas,as calculated by the analogy method, is 55,500×10;m;. This finding shows the high exploration and development potential of shale gas in the basin.
文摘Exploration and development experience show that there is obvious oil gravity difference between the southern part and northern part of the ＂M1＂reservoir in the Fanny oil field in the slope of the Oriente Basin, Ecuador. The American Petroleum Institute Gravity （API） values of oils in the northern part are higher than the one in the southern part of the Fanny oil field, with the values of 20° and 10.0°-13.0°, respectively. So the primary purpose of this study was to analyze the heavy oil characteristics of biodegradation and the oil-oil correlation according to the biomarker data and the δ^13C signature of oil samples from T block. The results of the hydrocarbon gas chromatography fingermark and the inversion attribute characteristics indicated that there are fluid compartments between the ＂M1＂ reservoir of Fanny south. Finally, the models of oil-gas accumulation under the control of multiple-activities of complicated fault systems, as well as the origin of heavy oil, are contended. The early stage oils from the western part of the basin were biodegraded heavily in varying degrees in the whole basin, and the later stage oils were derived from the southern part in a large scale and were mature and lighter. Generally, oil mixing is the primary control of net oil properties, such as API gravity in Oriente Basin. We therefore predicted that the API gravity variation of oil pools radically depends on the injection amount of the later stage oil. Because of the shale barrier in the ＂M1＂reservoir of Fanny south, the later stage hydrocarbon could not pass through and contribute to increase the oil API value.
基金the China National Science and Technology Major Project(No.2016ZX05002-006).
文摘The exploitation of a thin-layered reservoir with thickness less than 5 m(16 ft)needs to rely upon sedimentary facies analysis,due to the low resolution of seismic data and sparse well data.However,the ambiguity of facies interpretation creates uncertainty in facies and reservoir mapping.The study aims to better define facies distribution,predict sand-body architecture,and consequently reduce risks in planning development wells,by integrating production data(dynamic)with conceptual geological models(static).An example is shown from the M1 Member of the Napo Formation in the B and G Oilfields(Block J),Oriente Basin,Ecuador.The M1 reservoir is a thin-layered sandstone reservoir below seismic resolution.Core and well-log facies interpretation indicates depositional facies of a tidedominated estuary.Production data during the water injection phase of field development can delineate the detailed geometry of the sand bodies.The injector-producer rate responses can determine the connectivity of sand bodies.Well performance during primary recovery can capture the scale of single reservoirs because the initial production rates and the cumulative oil production of individual wells are generally proportional to the size of sand bodies.A facies model was thereby generated.Two step-out wells were planned using this model and drilled successfully.The results demonstrate that the integration of dynamic and static data is critical to understanding reservoir facies distribution.
