Microbially Induced Formation Damage in Oilfield Reservoirs

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractFormation damage in terms of physio-chemical reactions such as asphaltene deposition, scale precipitation and fines migration for example, is relatively well understood. In contrast to this the effects of indigenous and introduced microbes and their role in oilfield formation damage is less well understood. Oilfield microbes, especially the S.R.B. (sulphate reducing bacteria) have been identified from many oilfields world wide (indigenous) and have been isolated from drilling mud (particularly water based muds) and other downhole chemicals and injection water (introduced microbes).The combination of the various microbial populations often results in the precipitation of insoluble metal sulphides, biopolymer and/or hydrogen sulphide production, with loss in production or injection rates. By utilising bottle tests performed at a range of temperatures up to the actual oilfield reservoir temperature, it is possible to model the microbial formation damage mechanisms using the thermal gradients present in the field. Using this thermal model it is possible to predict where the various microbial formation damage mechanisms, such as hydrogen sulphide production, biopolymer and cell pore blockage, occur in the field area and to predict from the injection water model when the various damage mechanisms will occur in the field. This novel approach using thermal models coupled with microbial bottle and flood tests, and geological interpretative techniques, is the initial step in predicting microbial formation damage in oilfield reservoirs.

Minimizing Formation Damage in Drilling Operations: A Critical Point for Optimizing Productivity in Sandstone Reservoirs Intercalated with Clay

“…Chakraborty et al [36] concluded that a major explanation behind this phenomenon may be bioclogging-induced formation damage, which can occur mostly when the dominant factor-porosity-is lower than 24% [36]. Wood and Spark [37] studied bacterial induced damage-reaction mechanism in producing formations. They were utilising microbial bottle and flood analysis conducted at different temperatures up to the actual producing formation temperature modelled the microbial formation damage mechanisms.…”

“…They were utilising microbial bottle and flood analysis conducted at different temperatures up to the actual producing formation temperature modelled the microbial formation damage mechanisms. Wood and Spark [37] observed that native microbes can interact in different ways and induce formation damage reactions based on the different temperature values in the different regions of the reservoir, whereby those regions of the reservoir with temperature values of ~120 °C are habitats for pore-lining native bacteria, capable of inducing insignificant damage reactions, but those regions of the reservoir with temperature values of ~60 °C are home to a small number of pore-blocking microbes, which can induce significant damage reactions only when the population of the microbial community becomes large enough to occlude narrow micropore networks [37].…”

“…Wood and Spark [37] concluded that RDF produced organic compounds with heavy molecular weight and microbes at 30 °C, although a small volume of H 2 S gas evolved and was noticeable on produced H 2 O at the producing wells [37]. We acknowledge that temperature is a prime factor controlling the biological formation damage reactions due to microbes, and agree with Irene [31] that additives such as chemicals used to suppress microbes or oxygen-removing substances, when used for formulating RDF, can avert microbial damage reactions [31].…”

Microbial Control Management for Oil and Gas Recovery Operation

“…Microbes are known to survive and thrive under extreme conditions, produce hydrogen sulfide and cause souring of the wells and reduce hydrocarbon quality (1,2,3) . Microbes also have other negative effects; causing plugging or formation damage (4,5,6) and corrosion (7,8,9) . The impact of this biogenic fouling on infrastructure is expensive.…”