Earth models are important tools for support of decision making processes for optimal exploitation of subsurface resources. For geosteering and other real-time processes where time is a major constraint, effective mod...Earth models are important tools for support of decision making processes for optimal exploitation of subsurface resources. For geosteering and other real-time processes where time is a major constraint, effective model management is decisive for optimal decision support. During drilling, subsurface information is received which should optimally be used to modify the 3D earth model. Today this model is typically not altered during the operation. We discuss the principles of a novel method that enables a populated earth model grid to be locally modified when the topology (connectivity) of the geological structure is locally altered. The method also allows local updates of the grid resolution. The modelled volume is split into closed regions by the structural model. Each region is individually discretized and obtains its own subgrid. Properties are stored in separate functions, e.g. for each layer, and transferred into each subgrid via a mapping. A local update of the geological structure implies that only subgrids in regions that are directly affected by the updated structure must be discarded and rebuilt, and the rest of the populated earth model grid is retained. Our focus is on decision support for optimal well placement while geosteering. The proposed method aims to manage multiple model realizations that are never fixed and always locally updated with the most recent measurements and interpretations in real-time, and where each realization is always kept at an optimal resolution.展开更多
In this paper a case study is presented where refined 3D reservoir geology models, well pattern pilot test and Real-time GeoSteering tools have been integrated to optimize production performance of a viscous oil reser...In this paper a case study is presented where refined 3D reservoir geology models, well pattern pilot test and Real-time GeoSteering tools have been integrated to optimize production performance of a viscous oil reserve. The viscous reserves were of high structural dip angle. In addition delta depositional system represented highly variable geomorphology, where stacked sandbodies and shale bedding are crossing each other frequently. In order to keep a higher production rate, using horizontal wells along with water injection was not enough;therefore, detailed reservoir characterization, well pattern pilot experiment and GeoSteering were used to optimize previous development strategy and keep horizontal trajectories safely landing into reservoir target zone. The stratigraphic sequence architecture that is derived from seismic interpretations captured the variation within these high dip structural backgrounds very effectively. The best combination of choices was “Injecting Water outside from OWC” and “Stair Shaped Horizontal Trajectories”. The borehole collision risks of these optimized strategies were then analyzed and controlled successfully by the GeoSteering tools during trajectory landing process. The reservoir development performance is improved tremendously as result of these renewed development strategies.展开更多
In the Sichuan Basin,carbonate reservoirs are characterized by deep burial depth and strong heterogeneity,so it is difficult to conduct structure steering,pore space reservoir tracking and trajectory control in the pr...In the Sichuan Basin,carbonate reservoirs are characterized by deep burial depth and strong heterogeneity,so it is difficult to conduct structure steering,pore space reservoir tracking and trajectory control in the process of geosteering logging while drilling.In this paper,a series of corresponding techniques for structure,reservoir and formation tracking were proposed after analysis was conducted on multiple series of carbonate strata in terms of their geologic and logging response characteristics.And investigation was performed on the adaptabilities of the following logging technologies to geosteering while drilling,including gamma ray imaging while drilling,resistivity imaging while drilling,density imaging while drilling,gamma ray logging while drilling,resistivity logging while drilling,neutron logging while drilling and density logging while drilling.After while drilling information was thoroughly analyzed,the logging suites for four common types of complicated reservoirs(thin layered reservoirs,thick massive reservoirs,denuded karst reservoirs and shale gas reservoirs)were optimized,and five logging combinations suitable for different formations and reservoirs were proposed,including gamma ray logging t porosity t resistivity imaging,gamma ray logging t resistivity imaging,gamma ray logging t porosity t resistivity logging,gamma ray imaging t resistivity logging,and gamma ray logging.Field application indicates that it is of great reference and application value to use this method for the first time to summarize logging while drilling combinations for different types of carbonate reservoirs.展开更多
文摘Earth models are important tools for support of decision making processes for optimal exploitation of subsurface resources. For geosteering and other real-time processes where time is a major constraint, effective model management is decisive for optimal decision support. During drilling, subsurface information is received which should optimally be used to modify the 3D earth model. Today this model is typically not altered during the operation. We discuss the principles of a novel method that enables a populated earth model grid to be locally modified when the topology (connectivity) of the geological structure is locally altered. The method also allows local updates of the grid resolution. The modelled volume is split into closed regions by the structural model. Each region is individually discretized and obtains its own subgrid. Properties are stored in separate functions, e.g. for each layer, and transferred into each subgrid via a mapping. A local update of the geological structure implies that only subgrids in regions that are directly affected by the updated structure must be discarded and rebuilt, and the rest of the populated earth model grid is retained. Our focus is on decision support for optimal well placement while geosteering. The proposed method aims to manage multiple model realizations that are never fixed and always locally updated with the most recent measurements and interpretations in real-time, and where each realization is always kept at an optimal resolution.
文摘In this paper a case study is presented where refined 3D reservoir geology models, well pattern pilot test and Real-time GeoSteering tools have been integrated to optimize production performance of a viscous oil reserve. The viscous reserves were of high structural dip angle. In addition delta depositional system represented highly variable geomorphology, where stacked sandbodies and shale bedding are crossing each other frequently. In order to keep a higher production rate, using horizontal wells along with water injection was not enough;therefore, detailed reservoir characterization, well pattern pilot experiment and GeoSteering were used to optimize previous development strategy and keep horizontal trajectories safely landing into reservoir target zone. The stratigraphic sequence architecture that is derived from seismic interpretations captured the variation within these high dip structural backgrounds very effectively. The best combination of choices was “Injecting Water outside from OWC” and “Stair Shaped Horizontal Trajectories”. The borehole collision risks of these optimized strategies were then analyzed and controlled successfully by the GeoSteering tools during trajectory landing process. The reservoir development performance is improved tremendously as result of these renewed development strategies.
基金Supported by“Well logging-based shale gas evaluation”,a sub-project of National Science and Technology Major Project(No.2011ZX05018-003)“Interpretation and supporting system development for electromagnetic wave imaging and well logging while drilling”,a China National Petroleum Corporation Science and Technology Major Project(No.2013E-3809).
文摘In the Sichuan Basin,carbonate reservoirs are characterized by deep burial depth and strong heterogeneity,so it is difficult to conduct structure steering,pore space reservoir tracking and trajectory control in the process of geosteering logging while drilling.In this paper,a series of corresponding techniques for structure,reservoir and formation tracking were proposed after analysis was conducted on multiple series of carbonate strata in terms of their geologic and logging response characteristics.And investigation was performed on the adaptabilities of the following logging technologies to geosteering while drilling,including gamma ray imaging while drilling,resistivity imaging while drilling,density imaging while drilling,gamma ray logging while drilling,resistivity logging while drilling,neutron logging while drilling and density logging while drilling.After while drilling information was thoroughly analyzed,the logging suites for four common types of complicated reservoirs(thin layered reservoirs,thick massive reservoirs,denuded karst reservoirs and shale gas reservoirs)were optimized,and five logging combinations suitable for different formations and reservoirs were proposed,including gamma ray logging t porosity t resistivity imaging,gamma ray logging t resistivity imaging,gamma ray logging t porosity t resistivity logging,gamma ray imaging t resistivity logging,and gamma ray logging.Field application indicates that it is of great reference and application value to use this method for the first time to summarize logging while drilling combinations for different types of carbonate reservoirs.
