Fracture Propagation Analysis from Inter-well Tracer and Microseismic Data
Following an inter-well tracer study for their field, an onshore group was given the results of the study in the format of spreadsheets and 2D charts. The spreadsheet data were particularly difficult to interpret and the group felt a 3D/4D visualization of the tracer results was critical to fully understand them. Furthermore, the group wanted to integrate the tracer data with other field data that could potentially help with the tracer interpretation, including offset well trajectories, well logs, property models, microseismic data and horizon surfaces.
Oil Reservoir Compaction; Risk Reduction for Drilling Infill Wells
During production, North Sea chalk reservoirs are commonly prone to severe compaction due to reduction in pore pressure—this increases the load on the rock matrix, resulting in compaction. In some extreme cases the result is seabed subsidence on the order of 10 meters. This magnitude of subsidence causes challenges to the existing production infrastructure, including the integrity of the drilled wells, and leads to geomechanical changes in the subsurface which can impact seismic travel times.
Infill Drilling Placement using Conditional Seismic Attribute Filtering
Infill drilling aims to tap previously undrained reserves in a mature hydrocarbon field. By definition, infilling happens later in field life and hence involves the analysis of greater volumes and a greater diversity of a priori data. Furthermore, the economics of infill drilling can be marginal. Therefore, a rigorous quantitative decision-making process is necessary to justify the economic risk required to implement drilling and production plans.
A Relief Well Planning Case Study
In the Gulf of Mexico, a drilling trajectory needed adjusting due to a recent update to the reservoir model. Although the change to the trajectory was minor, the shift of the placement of the 14-inch and 11 7/8-inch casing shoes invalidated the previously designed relief well plans. With a fast-approaching deadline for drilling operations, the well planning team had little time to make a new relief well plan that could (1) achieve the objectives of the updated target plan, (2) meet industry-standard relief-well design constraints, and (3) be ready to send for permitting.
Regional Structural Geological Modeling Through Fault Data Correlation
Onshore projects often span extensive areas, and coarse, basin-wide models are used in activities such as assessing regional stress patterns and stratigraphic trends, as well as planning rig schedules.
Well Location Optimization with Visual and Quantitative Analysis
An onshore team was tasked with producing a list of potential well landing locations based on attributes in a geological model. Four pad locations in the field were each given a set of 12 wells arranged in a radial pattern; the model’s potential target area covered a Z range of about 1650 ft. The well landing locations needed to be optimized to hit the model’s high Net to Gross (NTG) and Gamma Ray (GRD) areas because these two attributes had high confidence amongst the team. Finally, the potential well path landing options had to be easily visually ranked.