Naslov
Long-Term Cement Deterioration Under the Severe Sour Gas Conditions (a Case Study)

Autori
Krilov, Zoran

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, stručni

Izvornik
SPE ATW "Challenges and Solutions for Sour Oil and Gas Production" / Lockhart, Thomas P. - Richardson (TX) : SPE, 2003

Skup
SPE Applied Technology Workshop "Challenges and Solutions for Sour Oil and Gas Production"

Mjesto i datum
Stresa, Italija, 10.11.2003. - 13.11.2003

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
well cement; sour gas; deterioration mechanism; laboratory tests

Sažetak
The study is based on the case history of several wells at one of the largest gas condensate fields in Pannonian basin (Croatia) where the long term cement deterioration was indicated. The research was carried out in order to investigate the possible mechanism of impairment. After almost fifteen years of undisturbed production from naturally fractured carbonates in some cases the plugging across the perforated zone with unidentified debris, accompanied by water cut increase, jeopardized the future well service. The study involves the laboratory evaluation of the actual environmental downhole impact (high reservoir temperature, BHST > 180oC, sour gas: 22% CO2 and 150 ppm H2S) to the well cement as well as debris identification. Experimental results, simulating downhole conditions in laboratory and well logging survey, suggested that well cement, after a long-term exposure could be deteriorated loosing its compressive strength and integrity. The dominant mechanism of cement deterioration is caused by CO2 corrosion process in the form of carbonic acid leaching. The CBL log data verified the cement disintegration behind 7 in. casing after 15 years of well production period.

Izvorni jezik
Engleski

Znanstvena područja
Rudarstvo, nafta i geološko inženjerstvo

POVEZANOST RADA