Despite depths as shallow as 3200 feet, 20/40 ceramic was pumped in concentrations up to 18 ppg to accommodate non-Darcy and multiphase flow. Productivity of wells in the Arman field was improved by 2 to 5-fold, and significantly increased recoverable reserves.
This paper presents a case study of a successful hydraulic fracturing campaign in the Arman field in western Kazakhstan: the first large scale campaign ever performed by a western service company in Kazakhstan. The Arman field is a mature field, originally delineated in Soviet times, and currently producing from four of the original vertical wells, and from newly drilled deviated (30 to 60 degree) wells. The field is currently under waterflood in three of the producing zones, but formation water is also being produced from wet zones. There is significant gas production, since the wells are all producing below the bubble point, either with ESP's or rod pumps.
We believed that hydraulic fracturing had good potential for stimulation in this field since most of the wells were producing with a positive skin. In addition to the positive skin, the reservoir was normally pressured, and also depleted in some zones, limiting the amount of drawdown to about 1000 psi. The wells were also producing water and gas in addition to oil, which further reduced the oil production (by a variety of mechanisms).
In this paper, we first describe the hydraulic fracturing operations, and the specific actions taken to deal with difficult features of this reservoir. We then examine the production mechanisms in the reservoir and compare the pre and post-fracture production data. Finally, we evaluate the effectiveness of hydraulic fracture stimulation as a method for improving oil recovery in this type of moderate permeability reservoir under waterflood.
Author(s): Josef Shaoul, Halliburton, Pinnacle Technologies Delft; Edgar Folmar, Arman JV; Klaas van Gijtenbeek
Paper Number: SPE 75146