Chemical Composition of Deep Subsurface Waters of the Western Anadarko Basin

Dickey, Parke A.; Soto, Carlos Y.

doi:10.2523/5178-ms

Cited by 3 publications

(3 citation statements)

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“…One possible explanation for these findings would be the existence of a sulfur cycle in the cavity groundwater that involves sulfate reducers and anaerobic sulfur oxidizers that regenerated sulfate from sulfide. We assume that similar sulfur cycles may operate in subterranean oil fields, since sulfate-reducing bacteria have been isolated from subterranean oil fields whose formation water contained very low concentrations of sulfate [29,30]. In order to elucidate ecological niches and interactions among these bacteria, their isolation and physiological analyses in axenic cultures are needed.…”

Section: Discussionmentioning

confidence: 99%

Diversity and abundance of bacteria in an underground oil-storage cavity

2002

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Section: Discussionmentioning

confidence: 99%

Diversity and abundance of bacteria in an underground oil-storage cavity

2002

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“…Water flowing in such aquifers usually has low salinity and is young. According to Dickey and Soto (1974), in hydrodynamic aquifers "meteoric waters may be defined as waters that have been part of the hydrologic cycle recently, geologically speaking". In recognized hydrodynamic aquifers, the existence of fluid pressure isopleths is consistent with the direction of aquifer flow and the tilt of the contact.…”

Section: Dynamic Aquifermentioning

confidence: 99%

“…Where hydrocarbons are trapped deeper in the sedimentary basin, the flow in the aquifer leg may lead to the dynamic tilting of the OOWC. Dickey (1963), Dickey and Soto (1974) linked aquifer activity with chemical composition at the scale of the sedimentary basin, and showed that highly saline brines are characteristic of static aquifers. Of special importance for this paper was the concept introduced by Bond (1973Bond ( , 1975 of aquifers in static equilibrium even though changes in hydraulic head were measured.…”

Section: Introductionmentioning

confidence: 99%

Tilted original oil/water contact in the Arab-D reservoir, Ghawar field, Saudi Arabia

Stenger¹,

Pham²,

Al-Afaleg³

et al. 2003

GeoArabia

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A review of the electrical logs, fluid properties, and production history of 195 flank wells drilled in the Arab-D carbonate reservoir of the Ghawar field, Saudi Arabia, showed that the original oil/water contact was regionally tilted. The contact was about 200 ft higher in the southern Haradh sector than in the northern Shedgum and ‘Ain Dar sectors. In Haradh, the fluid contact was also locally tilted down from west to east by as much as 800 ft. In the reservoir, the oil and aquifer densities changed from lighter oil and denser water in the north to lighter water and denser oil in the south. Decreasing methane content caused the increase in oil density and a reduction in the water density was the result of a salinity decrease. The evolution of fluid densities was closely correlated to a decreasing regional-scale geothermal gradient, probably indicating that temperature controlled the distribution of fluid densities. Simple analytical calculations showed that the magnitude of the observed tilt of the original oil/water contact from north to south might be explained by changes in fluid densities. On the western flank of central Haradh, the Arab-D reservoir water was anomalously young and fresh and this created a large salinity gradient between the western and eastern aquifer legs. This anomaly was explained by pressure-dependent vertical leakage along the Wadi Sahba structural trough between the Arab-D reservoir and the shallower Biyadh aquifer. Consequently, the integrity of the Hith Formation seal above the Arab-D reservoir might be locally compromised under particular conditions. A full-field reservoir simulation model, specific geological features, and examples from the technical literature supported a static interpretation of the tilted original oil/water contact in the Arab-D reservoir of Ghawar through the combined effects of changes in oil and water densities.

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Experimental Investigation of Waterflood Performance Challenges in a Low-Permeability Morrowan Sandstone Reservoir: Implications for Mechanistic Modeling and Enhanced Oil Recovery Optimization

Morgan,

Ampomah,

Grigg

et al. 2024

SPE Western Regional Meeting

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An indispensable factor to the development of improved enhanced oil recovery (EOR) is the in-depth insight into the fractional flow mechanistic effects of waterflood performance. Especially for an inefficient waterflood operated field. In this study the inefficiency of waterflood on FWU is investigated. The field is divided into two halves (East and west) of the same reservoir and similar geological characteristics. Though the east was prolific on primary recovery it failed on waterflood whiles the west performed efficiently and hence its undergoing WAG CO2-EOR improved recovery technique. Through core-flood experiments, the causative mechanisms are unraveled. X-ray diffraction (XRD), scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM/EDS) analyses were also conducted to assess mineral composition, pore characteristics and distribution. The core samples exhibited extremely low permeability, resulting in a drastic reduction in flow capacity. The reservoir primarily consists of quartz, clay minerals (kaolinite, illite, smectite), feldspar, and carbonates. Single-phase injection of low salinity water (SIIW) further reduced permeability and increased differential pressure compared to high salinity water (SCW). Higher flow rates caused significant increments in differential pressure, likely due to velocity-induced fine migration. pH changes and the presence of Al3+, Fe2+, and Zn ions indicated brine reactions. Two flood recovery strategies showed incremental recovery with SIIW injection with observed adverse effects. Fine migrations, clay swelling, scaling, and precipitation were identified as key causes of formation damage during low salinity water flooding. Element-mineral associations showed clays and mineral particles obstructing pores and pore throats. In summary, the principal mechanisms of waterflood inefficiency include low permeability, mineral composition (especially clay minerals), clay mineral reactivity, and increased pressure drop (ΔP). These factors collectively contribute to formation damage, pore plugging, reduced flow capacity, and ultimately the inefficiency of waterflood operations. These insights contribute to the development of effective waterflood strategies and improved recovery techniques for incremental recovery from the FWU-east field especially considering CO2-WAG EOR.

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Chemical Composition of Deep Subsurface Waters of the Western Anadarko Basin

Cited by 3 publications

References 0 publications

Diversity and abundance of bacteria in an underground oil-storage cavity

Diversity and abundance of bacteria in an underground oil-storage cavity

Tilted original oil/water contact in the Arab-D reservoir, Ghawar field, Saudi Arabia

Experimental Investigation of Waterflood Performance Challenges in a Low-Permeability Morrowan Sandstone Reservoir: Implications for Mechanistic Modeling and Enhanced Oil Recovery Optimization

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