TITLE:
Produced Water Geochemistry from an Upstream Oil Operation
AUTHORS:
Nasir Ullattumpoyil
KEYWORDS:
Formation Water, Petroleum Reservoirs, Groundwater, Ghawar Field, Tickler Plot
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.11 No.6,
June
28,
2023
ABSTRACT: Oil and gas industries generate a significant amount of water during the
production. The composition of this water varies with the geologic age, depth, and
geochemistry of the region along with the chemicals added during the process. Geochemistry of
formation water is used for aquifer identification, pollution problems, water
compatibility studies, corrosion monitoring, water-quality control, water
flooding, exploration, and to diagnose wellbore integrity issues. The current
study investigates the spatial and temporal variation of produced water
geochemistry from one of the largest conventional oil field, Ghawar field, Saudi Arabia. Produced
water from different wellheads were collected and analyzed for different
geochemical characteristics. Sixteen wells from ABQQ, nineteen wells from ANDR
and twenty wells from SDGM area were selected for the current study. Sampling
and analysis were performed as per the standard procedures. Results indicated
that the pH of the sample varied from 6.0 to 7.4, and Electrical conductivity
from 94200 to 102690 μS/cm. The spatial variation of major cations and anions
were also recorded and represented by graphical plots. Metal analysis indicated the highest concentration for boron, which is 20.5 mg/L at
ABQQ area, whereas all other metals are very low in concentration. Temporal
variation of a single well at SDGM area indicated drastic change in the ionic
concentration, whereas the geochemistry remains same as indicated by Tickler
plot. The water type of the respective area was studied by tickler plots, which
indicated same source of formation water in different wells at ABQQ, ANDR and
SDGM areas. The ionic concentration is also used to predict corrosion and
scaling issues. By Langelier Saturation Index (LSI) and Ryznar Stability Index
(RSI), the sample from all the wells showed
higher scaling potential. The study concludes that the water type in different
areas under Ghawar field remains same regardless of drastic changes in the
ionic concentration, which can be used to diagnose wellbore integrity issues.