Abstract
For a well in the Permian Basin, openhole (OH) triple combo logs from five nearby offset wells and gamma ray from a horizontal well were used to deduce a workflow to define the 3D structural geometry of the drilled horizontal section. After establishing the structural architecture of the drilled lateral section to determine which part of the lateral is in or out of zone, lithology and petrophysical properties from the offset wells were propagated using geostatistical algorithms to match the horizontal well path. A relatively distant offset well with an advanced log suite was also utilized to generate synthetic mechanical rock properties along the lateral. These data were used for optimized completion design by placing stimulation stages in similar rock and intelligently placing perforation clusters. Placement was guided by rock type and geomechanical properties as opposed to geometrical spacing along the lateral.
The assumption that rock properties are homogenous and structural dip is fairly constant in horizontal drilling has been proven to be untrue in recent studies, and production logs have shown that not all stages/perforation clusters contribute to production. The consequence of not using image log measurements in geosteering the lateral to ensure that the lateral is in the target reservoir can lead to ineffective stimulation treatment and possibly skipping stages in parts of the lateral that is landed in a higher stress rock.
The successful application of the workflow enabled us to determine the structural geometry along the drilled horizontal well and also build a 3D structural and property model, which was successfully used for the optimized stimulation staging and completion design. This produced a more successful stimulation treatment with approximately 67% more sand placed per stage compared to an offset well drilled in the same target zone.
