Permeability/Fluid Type/Rock Mechanics - Mississippian Application
Charles Smith and Lynda Ziane
The Mississippian is a difficult, altered lime reservoir with significant secondary porosity. Production generally is from horizontal well bores and has a very high water cut. Data was acquired in several pilot holes where full cores were taken and analyzed. Many different logging technologies were included in the data acquisition process and the results compared to the core data. This data can be used to determine the best location for horizontal drilling and the best techniques for completion to minimize the water production and maximize the oil production. Advancements in the physics of measurement and details of analysis have generated great confidence in the basic measurements of nuclear magnetic resonance (NMR) logs. The measurement of total porosity is directly determined by this technology since the only response is from fluid in pore spaces. Permeability calculated from the NMR measurements is less straightforward. Any ability to remove subjective inputs from analysis is a desirable objective. This paper will compare the results of porosity, effective porosity, and permeability from NMR to these same values as determined by lab work on the cores. The comparison of permeability will be made using the Bray-Smith permeability algorithm derived from relaxation (T2) with no other external inputs. Fluid type, independent of resistivity, will be determined using the polarization (T1) measurement. Fracture treating is also an important consideration; effectiveness of fracture treatment will affect flow rates from a horizontal Mississippian well. Rock mechanical data derived from dipole sonic measurements in vertical and horizontal wells is discussed. The value and application of this data to the completion is considered and discussed.
AAPG Search and Discovery Article #90176©AAPG Mid-Continent Meeting, Wichita, Kansas, October 12-15, 2013