Precise Determination of Probable Leak Path and Associated Source Noise with The Novel Technique of “Beamforming” Using Multiple Hydrophone Arrays; A Case Study from Sanggar-06 Well Indonesia

Abstract

The Beamforming technique was proven to leverage noise detection with multiple - hydrophone, it was designed to process the multiple waveforms from hydrophone in the frequency domain and modeled the delay time of leak signal arrivals between the hydrophones in order to locate the accurate leak position and flow path. The purpose of this paper to show the combination of these techniques that are -provide critical information for further plans to restore well barrier condition.

Sanggar-06 well has a mechanical problem on the 5-1/2” Tubing connection after the completion program in 2004, it was detected some joints was not tightened properly as shown by Caliper Survey. Based on daily monitoring in early 2011, the tubing pressure and A-Annulus pressure at the same pressure level and indicated continuous communication both in shut-in and flowing  conditions. The first noise log survey was run in May 2011 and detected 2 leak points, later the leak path was isolated with Tubing Patch by April 2012 and solved the problem.

In March 2017 the Sanggar-06 exhibited the same problem of communication between Tubing and AAnnulu.s, this was then followed up with 2nd run of the noise log.The result from this noise log run did not show a clear indication of where the leak position was located and indicated a 7-point potential leak position on the production string.

Before the decision to have a retubing program to recover the tubing integrity, the 3 noise log was run by adding 3 hydrophones (a total 6 hydrophones) and implementing a beamforming technique to locate the leak point. The re-run was paid off with the result by that confirming a leak point at the from packer assembly.

The benefit of this work has resulted in changes of the original tubing integrity recovery plan that use work over rig to rigless activity; which have impact massive or cost saving terms of restoring the well barriers objective in the execution of this operation.