Residual Land Subsidence Over Depleted Gas Fields in the Northern Adriatic Basin

Abstract

Research Article| January 01, 1999 Residual Land Subsidence Over Depleted Gas Fields in the Northern Adriatic Basin DOMENICO BAÚ; DOMENICO BAÚ Dipartimento di Metodi e Modelli Matematici per le Scienze Applicate, University of Padova, Via Belzoni 7, 35131 Padova, Italy Search for other works by this author on: GSW Google Scholar GIUSEPPE GAMBOLATI; GIUSEPPE GAMBOLATI Dipartimento di Metodi e Modelli Matematici per le Scienze Applicate, University of Padova, Via Belzoni 7, 35131 Padova, Italy Search for other works by this author on: GSW Google Scholar PIETRO TEATINI PIETRO TEATINI Dipartimento di Metodi e Modelli Matematici per le Scienze Applicate, University of Padova, Via Belzoni 7, 35131 Padova, Italy Search for other works by this author on: GSW Google Scholar Environmental and Engineering Geoscience (1999) V (4): 389–405. https://doi.org/10.2113/gseegeosci.V.4.389 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation DOMENICO BAÚ, GIUSEPPE GAMBOLATI, PIETRO TEATINI; Residual Land Subsidence Over Depleted Gas Fields in the Northern Adriatic Basin. Environmental and Engineering Geoscience 1999;; V (4): 389–405. doi: https://doi.org/10.2113/gseegeosci.V.4.389 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search nav search search input Search input auto suggest search filter All ContentBy SocietyEnvironmental and Engineering Geoscience Search Advanced Search Abstract An original nonlinear three-dimensional finite element model is developed to predict the residual land subsidence adjacent to depleted gas fields, as a delayed response from an active aquifer which may keep on compacting for a long time after the field abandonment. The pore pressure recovery within the reservoir and the depletion of the lateral/bottom aquifer are simulated by a subsurface flow model coupled with the equation of state of the residual gas repressurized by the ground water which floods the field. The resulting pore pressure distribution is used as input data in a poro-elastic structural model of land subsidence. The modeling approach is nonlinear because of both the dynamic coupling between the flux from the aquifer and the reservoir gas pressure response, and the dependence of the porous medium elastic properties on the effective intergranular stress and the loading/unloading conditions. The model is applied to the 3,000 m deep gas reservoir of Dosso degli Angeli, one of the major fields in the Northern Adriatic sedimentary basin, made of three major gas pools. Representative basin-scale mechanical parameters have been obtained from laboratory triaxial and oedometric tests, density logs, and recent measurements of in situ compaction by the use of radioactive markers. In 1992, at the end of 21 year production life the maximum pore pressure drawdown in the depleted pools approached 300 kg/cm2. The largest land settlement from the modeling simulation turns out to be 31 cm, in good agreement with the available leveling records. Numerical predictions suggest that a residual land sinking of about 10 cm is yet to be expected in 2042, i.e., 50 years after the field abandonment, close to the areas of Porto Garibaldi and Casal Borsetti a few kilometers south and north of the field, respectively, namely between two and three times the subsidence experienced by those areas during the field development. Gas pressure recovery in 2042 ranges from 50 to 130 km/cm2 according to gas pool, and with the cone of depression still expanding toward the far outer boundary of the adjacent aquifer. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.