Direct Wireline Logging Through Sidetrack Casing Window in Offshore Sisi Nubi, Mahakam Field

Abstract

As part of operation optimization in offshore Mahakam, a new method to run open hole wireline logging through sidetrack casing window has been introduced. Previously, pipe conveyed logging method was used to run wireline logging in sidetrack well. Despite quite long time is needed to run the wireline logging; this method is considered to be safe as it will prevent damage on wireline cable when passing through sidetrack window. At the moment, Mahakam reserve is getting marginal, simpler operation must be introduced in order to achieve economic limit of the well without sacrificing safety aspect.

A new method to run direct wireline logging in a sidetrack well is considered to be solution to reduce wireline logging duration when drilling sidetrack well. Shifting from pipe conveyed logging to direct logging mode can reduce logging duration up to 3 days of operation time. However, there is an increased risk of wireline cable fails at the sidetrack window in case of overpull during logging stuck in open hole. The risk has to be assessed and proper risk mitigation has to be created in order to ensure readiness of the trial in Sisi Nubi field. A new method to conduct surface e-line cable testing has been prepared, this test can simulate real condition when wireline logging is passing casing window area under high tension force condition. The testing method can generate a quantified risk of e-line cable failure on the window area. The result of the test then will be used as a basis to define limitation for wireline logging job in the sidetrack well. The first trial has been successfully executed at Sisi Nubi field and contribute to reduction of 3 days for wireline logging job which is equivalent to 700,000 USD cost saving. From the post job analysis, there is no indication of significant damage to wireline logging cable for both the armor and the internal part of the wireline logging cable.