Horizontal Well Completion Optimization Using Acoustic Logs in the Marcellus Shale
Eric Wigger¹, Kirby Walker², and Kevin Wutherich³
¹Schlumberger Data Services, Oklahoma City, OK, [email protected]
²Schlumberger Well Services, Pittsburgh, PA, [email protected]
³Schlumberger Well Services, Pittsburgh, PA, [email protected]
This project demonstrates the effective use of tractor conveyed wire-line tools to engineer stage placement and perforation spacing in horizontal wells drilled in the Marcellus Shale. While many operators drill vertical pilot wells to determine the ideal lateral landing point based on wire-line logs, very few horizontal wells are logged to determine how reservoir and mechanical properties vary as the well progresses away from the vertical data set. The majority of completion designs rely on geometric stage and perforation spacing, which neglects the heterogeneity of physical properties of the rock layers traversed by the well. Not accounting for the rock properties’ changes along laterals has led to varying production rates between sister wells from the same pad, non-producing perforation clusters, and an increased risk of screening out during completion.
For the project, eight horizontal wells were logged with a cross-dipole acoustic tool to assess completion quality continuously over the length of the laterals. Anisotropic mechanical properties computed from the acoustic data were then used to determine the optimal number and location of stages as well as the ideal number of perforations per stage and the perforations’ locations. Production logs run on two wells in addition to overall production and completion data were used to determine how successful the engineered completions were as compared to non-engineered, geometrically designed completions. A case study based on this data set shows the logged wells with designed completions had lower treating pressures and higher gas production rates compared to nearby geometrically completed wells. Additionally, no screenouts were experienced during the completion of the designed wells while previous geometrically spaced completions had screened out at a rate of 35%.
AAPG Search and Discovery Article #90154©2012 AAPG Eastern Section Meeting, Cleveland, Ohio, 22-26 September 2012