With the surge in activity in the Williston Basin, the ability to optimize completions has mainly been an expensive trial and error system. With the advent of sliding sleeve technology, operational efficiency could be gained; however, the effectiveness of the completion remained unclear. In order to get a large enough dataset to analyze the efficiency of different completion types, a considerable amount of time and money would have to be invested. This paper will present a workflow comparing different completion styles along a select number of wellbores through fracture pressure history matching and looking at the trends associated with the model outputs to get a better handle on an optimized completion design.
Creating a representative hydraulic fracture model (HFM) is a very iterative process. The HFM used in this work integrates specialty logs, core data and pore pressures derived from fracture injection tests. Three wells with varying completion types of open-hole (OH) sliding sleeve, OH RapidFrac sleeves, OH Plug and Perf and cemented Plug and Perf were fracture pressure history matched across all stages. After achieving matches on all stages, trends of propped fracture half-lengths, proppant concentration and propped fracture length area (PFLA) could be broken out by completion type. These parameters pointed to an optimal completion type. This optimized design was then put into place on two adjacent wells.
This workflow allowed for an in-depth look at completion type without having to drill and complete a large number of wells. A clear winner was evident, especially when examining PFLA within the pay zone and proppant concentration. The HFM outputs also provided insight into height growth out of the pay zone being attributed to higher rates and fewer entry points. A potential for refracs or hesitation fracs could also be seen with the HFM by integrating it with the microseismic data. All of these results went into an optimized design which was then field tested. Using the calibrated model, the resulting fracture geometries showed that the optimized design was achieving the expected results.
As operators move forward with pad drilling and down spacing of units, optimized completions will become more and more important. This paper will demonstrate how varying completion types can influence fracture geometry, propped fracture area and overall well performance and demonstrate a workflow to complete this somewhat daunting task.