Glenn Robert Mccolpin

Model Uncertainties and Resolution Studies With Application to Subsurface Movement of a CO2 Injection Project in the Krechba Field Using InSAR Data

Surface deformation-based reservoir monitoring technologies, such as Tilt, GPS and Interferometric Synthetic Aperture Radar (InSAR), have been successfully applied to monitor fluid flow or pressure changes in the reservoir and fluid migration to shallow depths. Obtaining the subsurface fluid movement from the surface deformation requires performing a geophysical inversion. To get meaningful results from the inversion process requires diligent selection of the inversion method and reservoir block sizes, as well as the application of physically reasonable constraints. The focus of this paper is to provide a workflow and guidelines for field application by studying the inverse problem, the solution methods and associated error estimates for the unknown model parameters, and the resolving power for each parameter. As a field case demonstration, the methodologies are applied to a CO 2 monitoring project with InSAR data. Also, the subsurface movement of CO 2 will be presented.

Field Validation of Transient Swab/Surge Response with PWD Data

This paper describes the results of field validation of the transient swab, surge model with PWD (Pressure while drilling) data. The maximum pressures encountered during tripping-or reciprocation are indispensable for making appropriate well completion decisions. The prediction of swab and surge pressures are of critical importance in wells where the pressure must be maintained within narrow limits of pore and fracture pressures. It also plays a major role in running casing, particularly with narrow annular clearances. For these critical cases, a fully dynamic model is required to better estimate the maximum pressures encountered. This paper presents actual surge and swab field data during tripping and circulating operations collected using PWD tools. These data were obtained from Alaska and North Sea wells with a range of hole diameters and with different base fluid muds. The data were compared and interpreted with a dynamic surge model, which includes the effects of fluid inertia and compressibility, wellbore elasticity, axial elasticity of the pipe, and temperature dependent fluid properties. The sampling rate was specifically increased to two seconds and in some cases one second. This is done to prevent downhole data attenuations and to capture the full waveforms more accurately. Different operations were included in the PWD runs to cover swabbing, surging, reciprocation and simultaneous pumping operations during tripping. Model predictions of downhole pressure behaviour were in excellent agreement with the measured PWD data.