Acidizzazione in Val D'Agri a "tasso massimo" - ENI, Baker Oil, Schlumberger
Acidizzazione in Val D'Agri con nuova tecnica ZCA.
Costi recuperati in una settimana,Halliburton
Grazie a tutto cio' la Halliburton ha fatto guadagnare all'ENI 25 milioni
di dollari in trivellazione orizzontale.
Ma di che mi sorprendo piu' ormai?
Ho iniziato a indagare la questione acido in Basilicata e cosa scopro? Che in realta' in Lucania acidizzano da sempre.
Dall'inzio.
Ecco cosa dicevano, e non ieri, ma nel 1999 su rivista della Society of Petroleum Engineers: hanno pompato acido HCl a tassi massimi da solo dall'inizio e in fase piu' sofisiticata con misteriose "pillole viscose".
Direttamente dalla penna dei capoccioni dell'ENI: S. Mascarà, A. D’Ambrosio, A. Zambelli, V. Gili, della Baker Oil, S. Loving e della Schlumberger, M. Dossena.
Menomale che era solo acqua e composti biodegradabili!!
Ecco qui:
Acid jobs have been performed using different procedures. Initially, in the dual completion vertical wells, the acid treatments consisted of bullhead pumping HCl acid at maximum rate without any flow diversion.
In the more recent horizontal wells the acid job procedure included two main operations. Spotting the acid in front of the formation with coiled tubing, then bullheading acid at the maximum rate intermixed with viscous pills.
Passa il tempo, e nel 2005 la Halliburton annuncia altre operazioni, in cui a causa dei *pozzi danneggiati dalle operazioni petrolifere* e per migliorare la permeabilita' dei pozzi stessi hanno deciso di "stimolare" i pozzi della Val D'Agri con una nuova tecnica, mai usata prima in Italia, la "ZCA" un zonal coverage treatment.
Per questo ZCA, la Halliburton ha lavorato a diretto contatto con l'ENI, e' stato un "gran successo" e cosi hanno deciso di usare lo ZCA in altri pozzi di lucania e in altre parti d'Italia.
I costi sono stati recuperati in una settimana, nessuno ha saputo niente, ci hanno guadagnato $25 milioni di dollari annui, e il nostro sottosuolo si e' beccato acidi di vario genere. Evviva!
Cos'e' la ZCA? E' una tecnica di stimolazione di pozzi orizzontali qui illustrata. Purtorppo non ho tempo per indagare i dettagli.
Beffa delle beffe... per saperne di piu' si puo' scrivere alla Halliburton!
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In the Val d’ Agri area in southern Italy, AGIP’s challenges were to remove near-wellbore damage caused by drilling operations and to improve the permeability of the carbonate formation. This required stimulating three
naturally fractured zones with different permeabilities in the 500-m openhole section. Halliburton, working closely with AGIP’s stimulation department, recommended a ZCA zonal coverage acid treatment. This would be the first ZCA treatment performed in Italy.
The ZCA treatment was bullheaded to the formation in two stages. After the second stage, tubing pressure changed from a negative to a positive slope. Once the well was put on production, it came in on its own. After cleanup, production
rates stabilized at 5,350 BOPD (850 m3/d) and 2.8 MMcf/D with a maximum potential of 10,000 BOPD (1,600 m3/d) and 4.5MMcf/D.
The job cost was recovered within one week. AGIP is applying the ZCA diversion technique in other wells in the same area as well as in their HP-HT wells in northern Italy.
The Val D’Agri field is located 20 Km SE of Potenza (Basilicata) in Southern Italy. The aerial extension of the field covers approx. 250 Km2 mostly (2/3) in the mountainous region (more than 1000 m. a.s.l.) of the field, while the remaining part is located in the river Agri valley at 600 m. a.s.l.
The field is divided into five blocks: Grumento Nova, Corleto Perticara, Caldarosa, Volturino and Tempa Rossa, operated by ENI Agip Division on behalf of different Joint Ventures, comprised by Enterprise Oil, FINA, and Mobil.
From 1980 to present 24 wells have been drilled by ENI Agip Division. The most significant discoveries have been Costa Molina 1(1980) and Monte Alpi 1 (1988), in the southern part, Cerro Falcone 1 (1992), in the northern part, and Monte Enoc 1 (1994), in the central part of the field which confirmed a unique reservoir. Val D’Agri is currently the most interesting Italian region for hydrocarbon production, and probably the most demanding from the completion technology point of view.
The overall plan is to drill more than 50 wells and produce about 100,000 bopd when the oil treating center and the pipeline network will be completed.
Introduction
In all the world (and the Val D’Agri is not excluded) there is considerable concern about the environmental effect of large scale development activity.
In Basilicata, in order to preserve the area’s environmental, archeological and rural worth, the area is going to be formally declared as a National Park; some of the wells already drilled and some to be drilled are inside its boundary.
To minimize the number of rig locations and in order to reduce the environmental impact in the area, cluster development has been implemented in Val D’Agri field. The carbonate reservoir has an average of 600 mt of undersaturated oil column. Two different types of oil are present; light oil at API° 35 and heavy oil at API° 22. The bottom of the reservoir is delimited by the acquifer at 2960 mt below s.l.
At present 4 wells are producing some 8,000 bbls/day treated in the Viggiano Oil Center; a further 13 wells have been drilled and completed , but are not connected yet. The Val D’Agri project involves the drilling of some 50 wells, the revamping of the Oil center to be able to treat more than 100,000 bbls/day and the construction of a 20” pipeline to the Taranto refinery.
Production test analysis suggest that most of the oil production comes from a few natural fractures and that the formation damage can be effectively removed with a properly designed acid job.
Acid jobs have been performed using different procedures. Initially, in the dual completion vertical wells, the acid treatments consisted of bullhead pumping HCl acid at maximum rate without any flow diversion.
In the more recent horizontal wells the acid job procedure included two main operations. Spotting the acid in front of the formation with coiled tubing, then bullheading acid at the maximum rate intermixed with viscous pills.
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