| dc.description.abstract | Controlled-source electromagnetic (CSEM) methods are inexpensive geophysical techniques that can be combined with petrophysical and petroleum engineering methods to improve our understanding of subsurface formation characterization and fluid monitoring. This dissertation investigates two forms of CSEM methods, electromagnetic (EM) induction logging and terrestrial CSEM, and their applications to petroleum engineering. Induction logging is a standard formation evaluation tool for characterization of electrical properties in the near-wellbore region. Terrestrial CSEM methods are better suited for far-field diagnostics away from a wellbore and have been established for a range of industry applications including CO2 storage, geothermal exploration, terrestrial hydrocarbon exploration, buried pipeline, and hydraulic fracturing fluid flowback. In these applications, the EM response of a conductive wellbore casing must be accurately modeled and included in response simulations.
This dissertation (a) provided a new approach for combining EM induction logging (via anomalous diffusion simulation) with nuclear magnetic resonance (NMR) fracture-pore diffusional coupling to improve micro-fracture density estimation; (b) developed a method for assisting hydraulic fracture placement for natural fracture corridor geologic targeting; (c) simulated induction log response effects for hydraulic and natural fracture interactions; (d) developed a 2-D integral equation (IE) forward modeling code for simulating the EM response of conductive wellbore casing; and (e) described an approach for modeling the EM response of conductive wellbore casing using a newly developed hybrid finite-element integral (FE-IE) equation method.
The methods used in this research include numerical NMR fracture-pore diffusional coupling simulation in multiple-porosity systems, 3-D FE numerical simulation of EM induction logging (via anomalous diffusion simulation), 2-D IE simulation of the EM response of conductive wellbore casing, and hybrid IE-FE simulation of the EM response for idealized fluid-bearing zones in an oil-field scenario. Results show that combining simulated EM anomalous diffusion with NMR can aid in distinguishing between micro-fracture fracture dimensions and density to improve fractured zone characterization, simulated EM anomalous diffusion may improve well production through better geologic targeting for natural fracture corridor depletion, and the hybrid IE-FE method improves FE solution stability while greatly reducing FE computation time by removing the need for an ultra-fine FE mesh around the wellbore. | |
