Environmental Impact of Untreated Produced Water: Hydrocarbon Analysis from Sadqal Oil & Gas Field, Pakistan

Abstract

Produce water without treatment from oil and gas fields causes contamination of the environment. This study was conducted to analyze the hydrocarbons present in produce water and soil of Sadqal Oil & Gas Field, Fateh Jhung, Pakistan. Sample points for produced water collection were identified and collected from outside the oil and gas field, from various locations including two ponds and their outgoing stream. While composite samples of soil were collected from adjacent pond area to analyze potential impacts of produce water on surrounding soils. Hydrocarbon analysis was conducted through GC-MS, area normalization method. Detailed analysis through GC-MS indicate that hydrocarbons i.e. saturated, unsaturated, cyclic and aromatic hydrocarbons were found in significant percentage in produce water and soil samples taken from outside oil and gas field. Saturated hydrocarbons and aromatic hydrocarbons found in a relatively higher percentage than unsaturated and cyclic hydrocarbons. Produce water samples without treatment contain average 46.86% saturated hydrocarbons and 38% aromatic hydrocarbons. While in soil samples unsaturated hydrocarbons present in the average percentage of 54.47% and aromatic hydrocarbons present in the average percentage concentration of 45.19%. In addition to these, unsaturated hydrocarbons were present in average percentage of 3.8% and 3.27% in water and soil, respectively while cyclic hydrocarbons were present in average percentage concentration of 1.54% and 7.21% in water and soil, respectively. Results reflect that continuous accumulation of hydrocarbons increased the concentration of hydrocarbons in soil lead to higher percentage concentration.  Moreover, results suggest that care should be exercised in the disposal and release of produced water containing these organic substances into the environment because of the potential toxicity of many of these substances. To reduce environmental impact there is a need to provide proper treatment for the removal of hydrocarbons from produce water so that their impacts on soil can be reduced.