Well blowout rates and consequences in California Oil and Gas District 4 from 1991 to 2005: implications for geological storage of carbon dioxide

Abstract

Well blowout rates in oil fields undergoing thermally enhanced recovery (via steam injection) in California Oil and Gas District 4 from 1991 to 2005 were on the order of 1 per 1,000 well construction operations, 1 per 10,000 active wells per year, and 1 per 100,000 shutin/idle and plugged/abandoned wells per year. This allows some initial inferences about leakage of CO2 via wells, which is considered perhaps the greatest leakage risk for geological storage of CO2. During the study period, 9% of the oil produced in the United States was from District 4, and 59% of this production was via thermally enhanced recovery. There was only one possible blowout from an unknown or poorly located well, despite over a century of well drilling and production activities in the district. The blowout rate declined dramatically during the study period, most likely as a result of increasing experience, improved technology, and/or changes in safety culture. If so, this decline indicates the blowout rate in CO2-storage fields can be significantly minimized both initially and with increasing experience over time. Comparable studies should be conducted in other areas. These studies would be particularly valuable in regions with CO2-enhanced oil recovery (EOR) and natural gas storage.

Salinity of deep groundwater in California: Water quantity, quality, and protection

“…The 34,392 available depths of these 192,925 wells range from 0 to 8,696 m, with many wells penetrating through different formations. Wellbore integrity issues occur in a wide variety of wells and conditions and have been linked to fluid leakage (45)(46)(47)(48)(49)(50). Some of the existing wells can potentially act as leakage pathways and connect deeper, more saline formations to shallower, fresher groundwater (51,52).…”

Can We Treat CO2 Well Blowouts like Routine Plumbing Problems? A Study of the Incidence, Impact, and Perception of Loss of Well Control

“…This literature further shows that the social amplification of risk can result in a situation where the public perceives risk to be greater than indicated by statistical evidence showing a risk to be unlikely, preventable, or manageable through project operation and comprehensive regulatory oversight [6]. For example, even though the very small statistical likelihood of complications during operations [7,8] signifies that the oil and gas industry and their regulators routinely understand and mitigate the risks to well integrity during operations, the public remains largely unaware of such safety practices. The potential for the public to overestimate risk is stronger when the risk is unfamiliar and/or the impact is feared or dreaded [9].…”

“…More broadly, attempts have been made to quantify the risks of well blowouts within the offshore and Gulf Coast [13,14], and to examine how other analogous oil and gas operations can relate to CO 2 -specific risks [7,8]. There has been little in the way of studies that consider the potential impacts of these events on public perception or review the availability of information to respond to potential concerns.…”

Geochemical Implications of CO2 Leakage Associated with Geologic Storage: A Review

“…The first is where there is a sudden, fast and short-lived release of CO 2 as would occur in the case of well failure during injection or spontaneous blowouts (Holloway et al 2007;Jordan and Benson 2009;Damen et al 2005;Skinner et al 2003). In general, this leakage scenario is anticipated to be rare (on the order of 1 every 10 5 wells year -1 ) with environmental damage confined to the vicinity of the accident (Holloway et al 2007;Jordan and Benson 2009). However, in cases where CO 2 concentrations are high enough, there is the potential for loss of human and animal life (Bachu 2008;Hepple 2005).…”