NMR and Resistivity Logging for Free Water Level Determination

The patent replaces the mechanical coring system with a logging system that uses nuclear magnetic resonance (NMR) and resistivity measurements. Instead of physically extracting rock samples through coring, the invention uses electromagnetic and magnetic field interactions to obtain reservoir characteristics non-invasively through well logging operations, thereby eliminating the time-consuming and costly coring process while maintaining measurement accuracy.

The patent introduces NMR and resistivity logging tools as intermediary devices between the wellbore and the reservoir formation. These tools serve as mediators that interact with the formation through electromagnetic fields to extract information about reservoir characteristics (porosity, permeability, saturation, rock type) without requiring physical sample extraction, thus resolving the contradiction between measurement precision and time loss.

The patent replaces the expensive mechanical coring operation with a more cost-effective logging approach using NMR and resistivity measurements. This substitution eliminates the costs associated with coring operations (equipment, personnel, sample handling, laboratory analysis) while providing equivalent or superior measurement precision through advanced geophysical techniques.

The patent creates a virtual copy of the reservoir formation characteristics through logging measurements rather than requiring physical copies (core samples). The NMR and resistivity logs provide a detailed representation of formation properties that can be analyzed without removing actual rock material, thereby reducing the substance loss and associated costs of coring operations.

The patent merges NMR logging and resistivity logging operations into a unified approach for determining FWL and rock type. By combining the complementary information from both logging techniques (NMR provides porosity and fluid distribution while resistivity provides saturation information), the invention achieves high measurement precision for FWL and rock type determination while maintaining the operational simplicity of conventional logging procedures.

The patent creates a composite measurement approach by integrating data from two different logging methods (NMR and resistivity). This composite technique combines the strengths of both methods to overcome their individual limitations, providing accurate FWL and rock type determination that neither method could achieve alone, while preserving the ease of operation of standard logging practices.