Chemical evaluation and hydrodynamic interpretation of flammable gas leaching from the shallow water well in Chamchamal Town, Kurdistan, NE of Iraq

Abstract

A wonderful event had taken place in the Gurgayi Fatah Village (5 Km to the north of Chamchamal Town), when gas and water are blowouts from a shallow drilled water well. Scientists and people hurry to view and investigate this phenomenon. The current study attempts to interoperate the factors behind gushing water and gas. Samples of gas and water were analyzed for gas composition and δ ¹³CH₄ isotope, major and heavy metals, and environmental isotopes δ¹⁸O and δ²H. The results of the hydrochemical analysis showed that Ca²⁺ and SO₄^2- are the dominant ions and the concentrations of heavy metals are below the detection limit. The values of δ¹⁸O and δ²H isotopes were -6.25 and -30.85 respectively indicating that the recharge of groundwater is recent. The dominant gas composition is Methane CH₄ with 84.5% volume per unit volume, while it characterizes by elevated hydrogen sulfide with a value of 17700 ppm.

The study revealed that the drilled water belongs to the first system (gravity hydrodynamic systems; where the water moves by the action of gravity from sites of high potential, and the major faults and fractures connecting the deep aquifers to the shallower. The high-pressure phenomenon is well known in Fatha Formation even more notable some oil wells along the foothill’s zones.