Abstract

The Formation Tester is a tool which is run in either open or cased holes on a conventional logging cable. Tests may be made rapidly and safely at various depths in the hole. The Formation Tester provides: a sample of the formation fluids, GORs, a means to determine accurate gas-oil, or oil-water contacts, bottom hole pressure data, an index to the permeability of the small zone adjacent to the tool.

There are many formation testing problems peculiar to soft formations. Development of solutions has been very successful. The problems encountered and their solutions were:

  1. The percentage of successful tests was less than expected because unconsolidated sands would not support the packer. This problem was almost completely solved by the introduction of the shaped charge and snorkel testers.

  2. The number of fishing jobs needed to be reduced. This problem was overcome by keeping the cable in constant motion so that hydrostatic pressure could not seal the cable to the wall of the hole.

  3. Interpretation was confusing. It was found after many tests that the amount of oil or gas recovered was the factor which determined what the ultimate production would be. The water produced should not be used as an indicator of final production.

The Wire Line Formation Tester has recently been used in cased holes with very good success. The operation and application are similar to those in open holes with the following additional applications: old wells may be tested, cement jobs can be evaluated for channeling, directional holes may be tested without wire line hazards.

Introduction

The Wire Line Formation Tester has, in the past year, become widely used and is now becoming a standard tool for formation evaluation in Southern Louisiana. During the first two years of testing the soft formations of these coastal regions, results were not as satisfactory as had been anticipated. Many problems were present. Many solutions were attempted. The purpose of this paper is to describe the equipment and techniques which have contributed to the recent success of the tester. In addition, the newly developed method of testing in cased holes will be discussed.

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