Marcellus Shale

Literature Review

Exam number: B036253 Introduction

My project aims at identifying fractures in Marcellus Shale in America using 3D 3C seismic reflection data. Fracture detection plays an important role in shale gas exploration, since the fracture influences the productivity of a hydrocarbon reservoir by increasing permeability and the recovery rate of the reservoir. Consider the scale of such fractures are too small that cannot be seen from seismograms, anisotropy theory is applied to evaluate the fracture density. (Andrey et al., 2000) PS converted wave is widely applied in anisotropic characterisation, especially combining with Vertical Seismic Profile (VSP) data collection geometry.

In the literature review, a general introduction about

It covers around 240,000 km2 in the United States, including parts of New Your, Maryland, and six other States. (Kargbo et al., 2010; U.S. Department of Energy, 2009) The estimation of gas amounts in Marcellus Shale is uncertain, however, current productivity indicates that the potential recoverable resources from the Marcellus Shale could be promising. (U.S. Department of Energy, 2009; United States Energy Information Administration, 2012)

The Marcellus Shale is poorly permeable, which makes gas productive level is low. However, some successful wells have a high productive rate, which is caused by numerous intersect fractures in these areas. The intersect fractures not only connect pores with gas, but also connect to each other so that they can finally reach the well to boost the production. (Schoenberg and Sayers, 1995) Thus, the fracture detection is critical in Shale Gas

The sources are placed at or near the surface, while the receivers are down in the well. The measurement of VSP data includes both the up going and down going seismic wave fields, as shown in figure 1. The down going waves are direct waves from source, while the up going waves are the reflections which is reflected from the target layer in the subsurface. The seismic waves only travel from the shallow layer once (except multiples), which means the predominant noise-surface waves-are not recorded in seismograms. (Hardage,