A great deal has been published in recent years regarding horizontal well technology. However, little has been pub-lished concerning high rate acid stimulation treatments in openhole sections in horizontal wells. In fact, several articles suggest that a lateral section must be cemented and cased for the appropriate zonal isolation.1 This paper is a case history of a lateral openhole completion which utilized a high rate acid stimulation, polymer gel blocks for diversion, and dynamic spectral gamma ray log analysis.
The Keystone Cattle Company Well No. 378-H, located in Winkler County, Texas was completed in the Wolfcamp Formation of the Flying "W" Field. The completion interval consisted of 1388 ft (423 m) of lateral, openhole section. A 200,000 gal (757 m3) multiple stage, foamed nitrogen acid stimulation was performed using polymer gel blocks for diversion. Five of the acid stages were tagged with three different radioactive isotopes. A spectral gamma ray log was used to identify the treatment intervals during the stimulation to effectively displace the polymer gel blocks.
This paper includes background on the well and objectives for the completion techniques used. The detail procedure and evaluation of the real-time pressure and logging data are also discussed.