This paper will address and discuss the planning and operational challenges encountered in non-routine wellwork operations / well interventions in ExxonMobil Exploration and Production Malaysia Inc. (EMEPMI) oil and gas fields off the east coast of Peninsular Malaysia.

The introduction will provide a brief overview of EMEPMI wells, typical conventional workover rig (CWR) and non-rig wellwork operations such as coiled tubing operations, well servicing and wireline/slickline work. Subsequently, case examples will describe the planning and execution of non-routine non-rig wellwork operations, namely:

  • Coiled tubing milling of tubing retrievable surface controlled subsurface safety valve (TR-SCSSV) dislodged flapper,

  • High angle coiled tubing operations; static bottom hole pressure (SBHP) survey, setting tubing plug and sleeve shifting at well angle in excess of 75o,

  • High angle coiled tubing operations; setting through tubing inflatable packers at 88o well angle,

  • High angle well interventions with slickline; slickline fishing, and

  • Hot tap milling of stuck closed production casing × production tubing annular (B Section) wellhead valve.

Finally, the conclusion of this paper will share general lessons learned from the case examples in terms of applying best practices, planning the work and executing the work.


EMEPMI operations are primarily concentrated and focused on the 42 platforms, 17 fields, 775 wells and over 1000 well completions offshore Terengganu (see Figure 1). The operation ranges from production activities to construction work, facilities maintenance and upgrade, drilling and wellwork.

EMEPMI wellwork activities involve primarily two (2) categories of work, namely well servicing and well workover. The type of wellwork jobs undertaken using wireline unit, well service unit, coiled tubing unit, electric line unit and conventional workover rig are further described in Table 1.

Table 1

These jobs could further be grouped into rig and non-rig activities. Zone switch (closing or opening sliding side doors or setting tubing plugs), gas lift valve (GLV) installations, pressure and temperature survey and production logging with slickline or electric line units are just a few of the many routine non-rig jobs undertaken in EMEPMI. These non-rig jobs would typically involve intervening either single or dual selective completions in oil and gas wells. An overview of EMEPMI oil well completion and reservoir description is given in Figure 2. Further illustration of well sketches for gas wells from the case examples of this paper will provide a general overview and perspective on gas well completions in EMEPMI.

Meanwhile, the non-routine through tubing live-well interventions to be discussed in the case examples will demonstrate the ability to successfully execute challenging non-rig jobs safely and efficiently with the combination of best technologies and best practices.

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