Improving Completion Techniques of Unconventional Shale Reservoirs through the Analysis of Geomechanical Properties and Fracture Imaging; A Study of Horizontal Velocity and Image Logs within the MIP-3H Marcellus Shale Well in Monongalia County, West Virginia

Abstract

Log data was acquired through the Marcellus Shale Energy and Environment Laboratory (MSEEL) along the lateral of the MIP-3H well. This unconventional shale-well was completed within the Marcellus Shale just above the Cherry Valley Limestone, which is one of the limestone stringers separating organic rich units of the Marcellus. Geomechanical moduli like Poisson’s Ratio (PR) and Young’s Modulus (YME) were generated using compressional and shear sonic logs to indicate zones of increasing brittleness as well as changes in formation strength. Cross plots of PR and YME are used to show the concentration of data points for each stage. The scattering of these moduli affects the distribution of energy during hydraulic stimulation. Along with YME and PR, the application of Lambda-rho and Mu-rho moduli allows for geomechanical analysis with relation to lithology and assists in locating brittle zones. Data points that lie in the weak and brittle zones are likely more easily fractured. Pre-existing fractures formed from maturation of the formation during the Permian are distributed throughout the well. The contrast between calcite and shale in wireline image logs allowed for easy fracture identification, and 1600 resistive (calcite-filled) and a few open pre-existing fractures were recognized on logs. Fracture intensity and distribution for each stage may contribute to changes within the moduli. Calcite within fractures likely alters the data points which can be tested with the use of bulk density or gamma ray logs. Research conducted shows that all fractures experience tensile failure during hydraulic stimulation and contribute to the complex fracture network. Hydraulic stimulation and potential production data was obtained with the used of fiber optics. The distributed acoustic sensing (DAS) data allowed for a comparison of the energy distribution during stimulation. High concentrations of pre-existing fractures and/or larger faults may cause an uneven distribution within stages. Distributed temperature sensing (DTS) data was used to record the production of each stage a year after completion and can be used as a general tool to compare effects of geomechanics on production. Analyzing geomechanical properties of stages within the MIP-3H well may lead to improved methods of well completion through the use of a more geological approach rather than a geometrical approach to stage and cluster spacing. More efficient completion techniques could increase overall production efficiency for unconventional shale reservoirs.

AAPG Datapages/Search and Discovery Article #90373 © 2019 AAPG Eastern Section Meeting, Energy from the Heartland, Columbus, Ohio, October 12-16, 2019