Life Cycle Assessment (LCA) of chemicals is gaining ground as a practical tool for comparing the overall sustainability of different chemical solutions, but is rarely used for comparing well construction fluid choices. A discussion of the relative merits and insights to be gained from combining LCA and total cost of ownership for identification of the most sustainable well construction fluid solution is presented, using high-density completion brines as case examples. The comparison is made using the Eco-Efficiency Analysis tool, which has a proven track-record from over 450 studies since the 1990's as a means of determining the relative costs and environmental impacts of different industrial chemical solutions. This approach to LCA has not been previously used in the upstream oil and gas industry, but could easily be extended to assess different chemical solutions and products in the future.
The methodology and the merits of the Eco-Efficiency tool in assessing the sustainability of well construction fluid are discussed in relation to a case study comparing two families of high-density completion fluids, viz. bromide and formate brines. The analysis includes emissions, material and energy use, toxicity and risk potentials as well as the overall operational costs of running the fluids. The results from the case study and four different scenarios were subjected to an independent scientific review and were discussed with two major operators. The results show clear differences between the sustainability of the two product families, particularly taking into account the costs of the entire operation. The use of the results for supporting management decisions is discussed and it is argued that using overall LCA and cost comparisons data for decisions can improve well construction economics as well as reducing potential environmental or human health impacts.