The Logging While Tripping (LWT) measurements are standard open hole API calibrated logging devices and meet all regulatory requirements for porosity and resistivity.
Unique Logging While Tripping Acquisition Method
The DEN and DUIN measurements are acquired through an electrically invisible, proprietary composite collar. The directly measured induction readings are identical to conventional open hole induction resistivity logs unlike other through-casing methods generating a calculated resistivity. The PRT measurement is acquired through a specialized steel windowed collar that is rated for drilling. The DEN provides accurate omnidirectional compensated density readings through the composite (or steel) collar without requiring formation contact.
The GR, SGR, CN, and DEN readings are taken through a specialized steel collar and are calibrated API measurements applicable in both open (GR, SGR, CN, DEN) and cased (GR, SGR, CN) holes. Data for GR, SGR, and CN can be acquired through the intermediate casing string on the normal trip out following the openhole logging run, thereby negating the need for mandated cased hole logs following drilling.
The LWT tools are pumped into specialized steel and/or composite collars when TD is reached. Logging takes place in memory during the normal pipe trip out of the hole.
Tools and sources are fully retrievable at all times during operations virtually eliminating any lost-in-hole situations.
New Resistivity Measurements
Cordax commercially offers resistivity measurements that do not require a composite collar for acquisition as with the Dual Induction Resistivity. These measurements include both Wave Propagation (PRT) and Laterolog Resistivity (LL) which allow LWT acquisition in a full range of well bore conditions and formation salinities. Acquisition is from a steel collar sonde run in conjunction with the conventional LWT steel collar. The respective resistivity measurements are run in combination with the standard LWT measurements of Gamma Ray, Spectral Gamma Ray, Density and Neutron. Full details can be found under New Technology Developments.