Thermal Desorption of Drill Muds and Cuttings in Ecuador: The Environmental and Financially Sound Solution

Abstract

Oil base mud cuttings present a complex and costly waste management challenge. Indirect thermal desorption in conjunction with fluid recovery and reuse is widely recognized as the most promising means of achieving the zero discharge goal. Indirect thermal desorption offers a unique combination of compliance assurance and economic benefits. Thermal desorption technology, referred to as TPS, developed by SCCEnvironmental was selected by partners Arco Oriente Inc., Agip Oil Ecuador BVand Petroecuador to provide drilling waste management and fluid recovery for apioneering E&P project located on Block 10 in the eco-sensitive Villanofield of Ecuador. Introduction The development of Block 10, in the Villano Field of Ecuador by Arco, Agipand Petroecuador is a prototype for the development of oil rich properties located in eco-sensitive regions. The Block 10 site is located at the headwaters of the Amazon east of the Andean Escarpment, one of the most biologically diverse and isolated areas on the planet. The operators were required to conduct an extensive series of environmental impact evaluations and the knowledge gained laid the groundwork for operational approval. A successful drilling waste management program was faced with three major challenges. The first challenge involved the construction and supply of an active drilling site by helicopter only. The region had not previously not been opened up to development and road construction was determined to present too great of an impact to the sensitive environment. To further reduce the impact;strict limitations were placed upon the drilling and facilities site footprint. This precluded the construction of large storage pits or bioremediation pads. The small single pad required long reaching horizontal wells to efficiently drain the structure. In turn these challenging wells required a synthetic oilbased mud to be successfully drilled. Finally, an oil on cuttings criteria of>1% (by dry weight) was imposed. Accessibility, cost of transport/supply, limited footprint and stringent environmental criteria demanded an innovative approach to drilling waste management. The operators selected the SCC Environmental TPS technology which proved integral to the success of this project, both environmentally and economically. Treatment consistently achieved results of an oil on cuttings average of 0.023% coupled with leachable TPH (Total Petroleum Hydrocarbon)concentrations of 2.7 ppm. Removal efficiencies exceeded 99.9% producing are covered linear paraffin base oil with no significant thermal fractionation and >1.0% (by volume) Basic Sediment and Water (BS&W). In keeping with the low impact mandate of the operation, on-site experimentation was conducted related to solids reclamation through re-vegetation. This experimentation yielded data which will be developed into a methodology to optimizere-vegetation of the treated cuttings following demobilization.

The use of low temperature thermal desorption technology in the treatment of drill cuttings

“…The use of oil base mud has led to improved shale stability, enhanced drilling rate and an average drilling performance of 49% was reported by Zupan and Kapila [3] for 311.5mm hole sections in the areas he analyzed. A new technology called Low Temperature Thermal Desorption Process was introduced which can reduce, the oil content of treated cuttings to less than 1% T.P.H which is in accordance with D.P.R.…”

“…The use of pseudo oil based mud (POBM) has led to improved shale stability and enhanced drilling rates particularly where polycrystalline diamond compact (PDC) drill bits are used [2]. An average drilling performance improvement of 49% was reported by Zupan and Kapila [3] for 311.5mm hole sections in the areas he analyzed. These two characteristics of POBM; better hole stability and faster penetrating rate plus its lubricating nature combine to give superior overall drilling performance [1].…”

Towards enhancing sustainable reuse of pre-treated drill cuttings for construction purposes by near-infrared analysis: A review

“…Drill cuttings are treated by non-biological methods such as drying (Schlumberger, 2016), solidification and stabilization (Akinlade et al, 1996;Shaffer et al, 1998;Fleming, 2000; Leonard and Stegemann, 2010; Opete et al, 2010; Ghasemi et al, 2017), incineration (Dugat, 1988), and thermal desorption (Zupan and Kapila, 2000;Onwukwe, 2014). In recent years, more hot technologies for treatment of drill cuttings have emerged, including microwave-assisted heating process (Robinson et al, 2009).…”

“…Thermal desorption includes (among others) thermal phase separation (DWMIS, 2000), which consists basically of five subsystems, namely; the pretreatment unit, the anaerobic thermal desorption unit (ATDU), the solids handling unit, the vapour recovery unit (VRU), and the water treatment unit (WTU) (Zupan and Kapila, 2000). At the pretreatment unit, the drill cuttings are screened to remove foreign and oversized materials (>50 mm in diameter) before delivery to the ATDU.…”

“…The condensed liquids and recirculated quenched water are then sent to the WTU where oil is separated from water. However, because of the indirect heating system of the ATDU, large heating surfaces that consume large amounts of energy and space are needed (Zupan and Kapila, 2000). Moreover, the operating temperature of 520°C for high temperature TDUs could lead to thermal degradation and decomposition of the residual drill cuttings (DWMIS, 2000).…”