Wireline Data Acquisition under Managed Pressure and Pressurized Mud Cap Drilling Condition – Pushing the Boundaries of Data Acquisition Envelop for Formation Evaluation

Abstract

There is a perception that conventional wireline logging operation in Managed Pressure Drilling (MPD) and Pressurised Mud Cap Drilling (PMCD) conditions is not feasible due to HSE risks associated with the operation. Rigging up a wireline assembly and safely performing the job while the well is experiencing total or partial loss circulation or potential gas migration is extremely challenging with currently available technology. However, with the new comprehensive technology, described in this paper, these challenges can be mitigated enabling acquisition of all desired formation evaluation data. MPD and PMCD techniques, with close loop adjustable back pressure, have gained wide acceptance. This is owed to the current market demand of drilling deep-water wells, with narrow mud windows and in fractured reservoirs, under total or partial loss conditions, safely and with optimum cost. To reduce the drilling risk, relatively simple drilling bottom hole assembly (BHA), with limited logging while drilling (LWD) tools, are preferred in such conditions. A new technological solution is desired to acquire complete formation evaluation data, on wireline, after drilling. Wireline well logging under this condition requires a non-standard and complex rig up, especially in the floater, to allow the operation to be performed safely but efficiently. With the new development of Managed Pressure Logging System (MPLS), an integration of Smart Sub System, and Grease Injection System, wireline operation can now be performed safely in active MPD/PMCD conditions. The newly developed smart sub, discussed in this paper, features an innovative system available for multiple operations including MPD/PMCD wireline logging. It provides the sought-after well control mechanism which allows wireline operations, through a side entry, without interfering with drilling rig's top drive system. The unique design of the sub is compatible with all industry-recognized grease injection and pack off systems used to maintain the desired pressure in the wellbore. When deployed with active PMCD condition, it creates a closed-loop system to enable the driller to continuously pump drilling fluid and adjust borehole pressure during wireline logging. This paper discusses the complete operational detail of a number of wireline logging operations performed in a deep-water well under MPD/PMCD condition. This includes planning, associated challenges, deployment risk assessment, standard operating procedure, and mitigation plan. The paper also incorporates standard data acquisition practices, results, lessons learned, and recommendations. This comprehensive workflow of wireline logging, with MPD/PMCD technique, and under total or partial loss condition, using the smart sub, pushes the wireline operating boundaries of data acquisition for formation evaluation, to places previously thought to be not feasible. This new solution has the potential to solve other challenging wireline deployments application including pipe recovery, pressurized cement bond evaluation and overbalance wireline perforation.