An Optimized Protocol to Expedite Pit Closure

摘要

Elimination of oily pits is a significant demonstration of environmental stewardship. A methodology was developed to simplify, expedite and optimize remediation and closure of oily pits at E&P facilities. Protocol development commenced with a lookback at over 400 historical pit closures to identify successful practices and improvement opportunities. The protocol was designed to eliminate process bottlenecks, incorporate recent advances in site characterization and remediation techniques, and embody the collective experience gained. The first step of the protocol is to compile an inventory of oily pits. A simple qualitative assessment addressing key drivers of potential risk is then used to prioritize the pits for characterization. Contrary to expectation, the lookback revealed that characterization generally constituted the longest-duration phase of pit closure. Recent advances in sampling and analysis technologies as well as value-of-information prompts were incorporated into the methodology to keep the characterization phase decision driven. Pit inactivation and content removal activities were included as part of the characterization step to enable full access for sampling. The lookback also indicated that two onsite treatment methods were used successfully to remediate hydrocarbon-impacted soil at about 90% of the locations. Simple predictive algorithms were derived to enable desktop evaluation of the feasibility of these two methods for a given pit, expediting remedial decision making. Land reclamation performed after remediation restores the area of the closed pit and renders it suitable for future use. Best practices in backfill profile design and revegetation were incorporated into the reclamation methodology. This paper will highlight the elements which significantly reduced the cycle time and advanced the state of practice.