Abstract

The Liquid Trapper tool was developed to address one of the biggest shortfalls of coring services, which is the loss of formation fluids during the coring process. Accurate oil and water saturations are even more critical when producing hydrocarbons through secondary and tertiary recovery. The Liquid Trapper™ design is based on 3-1/2 inch diameter core with a specifically designed inner liner assembly with independent inflatable seals which “traps” liquids escaping from the core during the trip out hole. The inner assembly is made of stacked modules, one meter in length and each made up of closed “cells”, which allow capturing of the expelled fluids. These cells isolate one meter sections of the core, thanks to specifically designed seals which prevent liquids from escaping. Each section has a top and bottom seal with a one way valve to allow gas to escape. The annular seals are activated when a ball is dropped to free a mechanical system at the end of each core run. Core and fluids can then be extruded at wellsite or at the laboratory. Benefits include direct measurement of the volume of recovered fluids and increased accuracy of water and oil saturations laboratory analyses. Recovered oil volumes can then be added to measured volumes of the adjacent core thus obtaining the total oil saturation of that core section. The Liquid Trapper Core System has applications to additional conventional and unconventional reservoirs to provide more accurate characterization of the core at reservoir conditions. Summaries of Liquid Trapper™ coring operations from West Texas are presented.