1965 Paper II-I

ABNORMAL SUBSURFACE PRESSURES MEASURED FROM CONDUCTIVITY OR RESISTIVITY LOGS

W. E. Wallace, February 1965 Forest Oil Corporation

Introduction

The following empirical method of pressure measurement is based upon the sensitivity of shale compaction to the overburden load and to the fact that some shales have not been able to lose sufficient water to adjust to that load because of the lack of sand or lack of sand continuity, i.e., means of escape. These shales will carry abnormal quantities of water and will for that reason have abnormally high conductivities. The high conductivity is related directly to the higher pressure in the next sand beneath that shale. This study is restricted to formations of Oligocene to Pleistocene age in South Louisiana only.