Design and Construction of Drilling Waste Management Facility in Mahakam Delta, Indonesia
Authors: Segret Gilles , Kemala Priyahita , Seaton Simon , Campbell Brian , Abbott Gregory Douglas 
Published: February 2016

The Mahakam delta of Indonesia ecosystem is highly sensitive. Mangrove and nypa palms flourish there and are under strict regulatory protection. A high level of commercial fishing activity and marine vessel traffic on the river also influence the approach to managing drilling waste over the long term. In preparation for a major drilling project in the Mahakam delta, Total E&P Indonesie (TI) evaluated several drilling waste management options. The option selected would need to meet the new Indonesian regulation specifying that waste disposed of in sensitive areas must contain less than 1% hydrocarbon content.

TI personnel reviewed several waste treatment alternatives, including cuttings injection, bioremediation, and thermal desorption (TD). This paper will outline the reasons why thermal desorption was the waste treatment process selected for this drilling campaign.

Once this process was selected, in order to meet the challenges of complying with TI and local regulations, the waste transfer and treatment process called for equipment upgrades to up to seven barge-mounted drilling rigs, as well as training for rig personnel in waste collection and transfer procedures. Specially designed barges were required to collect and deliver the drilling waste to a purpose built, central treatment facility that was designed to process up to 240 MT/day of oil-contaminated cuttings and 200 m3/day of oily water on a twenty four hour a day basis. This facility had to be built on a "greenfield" site in less than nine months. A fully-equipped laboratory also had to be installed in the facility, to allow comprehensive analysis of untreated and treated waste to be performed. The design and construction of the barges and the facility location as well as some key lessons learned, including plant performance and base oil recycling, will be discussed in detail in this paper.

Project Background

The Mahakam delta of Indonesia ecosystem is highly sensitive (Fig. 1). Mangrove and nypa palms flourish there and are under strict regulatory protection. A high level of commercial fishing activity and marine vessel traffic on the river also influence the approach to managing drilling waste over the long term. The proposed project comprised drilling operations in an area measuring approximately 5,000 km2, consisting of swamp and offshore locations (Fig. 2). Seven swamp barges were deployed to drill in the Tunu, Tambora and Handil fields, and two jack-up rigs were mobilized for the Peciko, Sisi and Nubi fields offshore.

In 2006, 97 wells had been drilled in the swamp and 15 wells had been drilled offshore, generating an estimated ±90,000 mT of water-based mud (WBM) cuttings and ±55,000 mT of low-toxicity oil-based mud (LTOBM) cuttings. Project plans also estimated that up to 300,000 m3 of oily water would require disposal over the life of the operations.

This was the first project of its kind in the region, and the Total E&P Indonesie (TI) team was committed to exceeding regulatory requirements and establishing a high standard for drilling waste management exceeding local and corporate requirements. Local regulations had become increasingly stringent and extensive environmental monitoring would play a critical role in the project's success. Per local requirements, the oil-on-cuttings (OOC) value for cuttings produced while drilling at the offshore sites was restricted to &lt;10%, and wastewater oil content was restricted to &lt;50 ppm. The restriction for cuttings produced at onshore locations was &lt;1% OOC, with a wastewater oil content limitation of &lt;25 ppm.

Cuttings Treatment and Waste Disposal Options

TI evaluated several drilling waste management options. At a minimum, the option selected would need to meet TI corporate policy restricting oil on cuttings (OOC) to 8% (offshore) and also satisfy the new Indonesian regulation specifying that waste disposed of in sensitive areas must contain less than 1% hydrocarbon content.