Fracture Spacing in Miss. Madison Ls

Recent Advancement Areas Log Characterization Spacing Estimates Fracture Zone Identification Reservoir Simulation Azimuth Predictions Reservoir Analogs Effects of Fracture and Diagenetic History

Log Characterization Acoustic & electrical imaging logs and their interpretative workstations are becoming the subsurface standard for data acquisition, rapidly replacing core. Dipole sonic logs are attempting to quantify fracture occurrence and fracture porosity.

Quantitative Fracture Analysis 270 W 360 N BOREHOLE Planar features are expressed by ellipses on borehole walls which are expressed as sine waves Steepness of ellipses reflect the dip magnitude and orientation Apparent strike and dip relate to amplitudes and inflections in sine waves For straight hole: Dip magnitude is proportional to amplitude of sine wave Dip azimuth is located at minimum of sine wave TD: 530 / 2700 W David Spain (1998)

Faults on FMI Fracture Trace TD: 62/304 Normal fault Striking: N25E-S25W Down to WNW Courtesy of Steve Hansen, Schlumberger 8

False-Color STAR Image Oil well in granite. RED : Acoustic amplitude GREEN Microtopography : BLUE Resistivity : Open fractures are black Green fracture is filled with somewhat hard, resistive, slightly erodible material. Courtesy A. Lacazette Depths in meters below arbitrary datum.

Different fracture types are different colors in multivariate images. Courtesy A. Lacazette 2

Fracture Summary Logs Dips computed from FMS Fracture intensity calculated using statistical analysis of images Fracture aperture (width) calculated (in mm) using resistivity calibration (Courtesy of Dave Spain)

Production Logging Techniques Lithology Flowrate Spinner flowmeters Temperature logs Noise Logs Perfs FractureWidth Fracture Density and Porosity (Courtesy of Dave Spain)

Fracture Zone Identification Seismic attributes Single Multiple

Study Area with 3-d Seismic Coverage Lake Maracaibo, Venezuela

Amplitude Map Top Socuy Lake Maravaibo, Venezuela Note Fault Traces

3-D Seismic data coherency : delineating faults and fractures (Courtesy of Robert Humphreys) Seismic coherency extracted along horizon TWT horizon Structure map

Courtesy of S. Agar