Abstract

Shale gas exploitation has dominated the E&P landscape in North America for nearly a decade. There is a great deal of competition for shale acreage in the US, and leasing occurs rapidly once a new shale play is discovered. It can cover tens of thousands of acres and are often selected based on limited data, mainly vintage paper logs, mud logs, and access, cost, and availability considerations. Rarely are core, seismic or modern log data available to the operator. Capturing data in exploratory vertical wells is crucial, but comprehensive integration of the data to optimize horizontal well design is often overlooked.

This paper discusses one operator's approach to fully integrate data captured in the Marcellus Shale in order to optimize horizontal well performance. Based upon insight from the study, the operator wanted to make more informed asset management decisions, improve economics, and look for future investment opportunities. Data were captured from vertical offset exploratory wells and an initial horizontal pilot well. The data that were acquired and incorporated into the study included field-wide seismic and data, as well as mineralogical, geomechanical, well plan, drilling, completion, microseismic, and production data from the aforementioned wells.

A comprehensive study was performed incorporating the data to optimize the design of a horizontal well in the Marcellus Shale. This study was performed to get the operator up the learning curve in a short time period rather than by trial and error on wells. The first step in the study involved constructing a field-wide 3D static geologic model using the data captured above to determine the best petrophysical and structural areas to drill new wells. A reservoir model was then constructed with existing production, fracture, and microseismic data as well as the geologic model. The reservoir model was then used to forecast various production scenarios, including lateral length, number of stages, and perforation cluster spacing. Various fracture models were also included in the analysis to determine height growth and complexity.

The results of these geologic, reservoir, and fracturing models were used to optimize the design of a second horizontal well drilled in the area of interest. The production increase between the first and second horizontal well was analyzed on a percentage basis. Lastly, recommendations were made for further well design enhancements based upon the study findings and the results of the second horizontal well.

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