A Real-Time Well Site Log Analysis Application Using MRI Logs

With any complex logging tool, there exists a need for a qualitative and reasonable analysis, run in real-time at the well site that both provides a preliminary interpretation of the data and also serves as a means for enhancing quality control. Such an application has been developed to provide a quick-look analysis of data from NUMAR's MRIL®-Prime tool. The application takes advantage of the Prime tool's ability to simultaneously acquire data from multiple nuclear magnetic resonance (NMR) activations for purposes of fluid identification. The application is based on several well-established NMR fluid-characterization methods. These methods compute total porosity, effective porosity, bulk volume irreducible, flushed-zone fluid volume, and fluid type in a variety of reservoirs. The methods used in quick-look analyses include the Differential Spectral Method (DSM ), Time Domain Analysis (TDA ), Shifted Spectrum Method (SSM ), Enhanced Diffusion Method (EDM ), and the Total Porosity Method (TPM ). Accomplishing these objectives, i.e., computation of total porosity, effective porosity, etc., in a real-time environment requires consideration of the wellsite engineer's level of experience and responsibilities. In addition, the dynamics of the real-time wellsite analysis presents several competing and important challenges: acquiring quality measurements, working with limited data and information, and providing results in a timely and efficient manner. Thus, a real-time analysis should be robust and consistent with any additional analysis done in the post-acquisition environment. A set of procedures has been developed to guide the process so that reasonable interpretations can be obtained over a broad range of operating conditions. To simplify the engineer's tasks, the analysis procedure is automatically driven by the type of NMR data being obtained. Thus, meaningful results can be obtained without increasing the burden on the field engineer. This paper briefly describes the techniques that have been developed and demonstrates their application through field examples.