Daqing Field - Alkaline-Surfactant-Polymer Project
The Daqing oil field is the largest field in the Peoples Republic of China. The Daqing field was discovered in 1959. Water injection into wells with no layer isolation began in June of 1960 with separate layer injection beginning in January of 1965. The field was developed in a line drive pattern with rows of injectors 2,400 meters (7,875 ft) apart and spacing between wells within a row of 500 meters (1,640 ft). Between rows of injectors are 3 rows of producing wells evenly spaced at 600 meters (1,969 ft) between rows. The oil production has been maintained at more than 160,000 m3/day (1,000,000 bbls/day) since 1979 by this in-fill drilling and development resulting in more than 10,000 wells. Artificial lift development began in January of 1981 continuing until December of 1989. Beginning in 1984 the reservoir characteristics were screened for the application of enhanced oil recovery techniques. Two polymer flood demonstration projects were performed beginning in 1987 with water cuts decreasing an average of 16% and oil rates increasing three-fold1. As a result of these demonstration projects, on-site polymer manufacturing facilities were built capable of producing 50,000 tons of polyacrylamide polymer per year.
With the polymer expansion project already planned, consideration was given as to further enhancing the performance. In 1993, a comprehensive program of ASP design, numerical simulation, and facilities design was initiated for testing ASP technology at Daqing. The adjacent figure shows the type of radial coreflood performance that simulated pilot testing. The first of two tertiary demonstration of the Alkaline-Surfactant-Polymer (ASP) process was initiated in September 1994 in the west center area of the Daqing Oil Field.2 The Alkaline-Surfactant-Polymer target sand layer in the project is the Saertu II1-3 sandstone formation. The reservoir slopes gently from east to west with an average depth of 814 m (2,671 ft). 35 o API gravity, 11.5 cp crude oil is produced. Reservoir temperature is 45oC (113oF). The Alkaline-Surfactant-Polymer project pattern consists of 4 inverted five-spots, including 4 injectors and 9 producers, as well as 2 observation wells encompassing an area of 90,000 m3 (22.2 acres) and with a pore volume of 203,300 m3 (1,280 Mbbls). The Saertu II1-3 sandstone has an average porosity of 26% and permeability of 1.426 m2 (1,400 md). The connate water salinity is 6,800 mg/L. The project performance shows a pronounced response due to Alkaline-Surfactant-Polymer injection. The average project oil production rate increased from 36.7 m3/day (231 bbls/day) to 91.5 m3/day (576 bbls/day), while water cut decreased from 82.7% to 59.7%. For the central well Po5, which is surrounded by the four injection wells, the oil production rate increased from 3.7 m3/day (23.3 bbls/day) to 27.1 m3/day (170.5 bbls/day) while water cut decreased from 87.9% to 45.8% (a 42.1% decline). The oil recovery from the project has exceeded 20% OOIP and SURTEK estimates the ultimate incremental oil recovery will be 31% OOIP. As a result of this project, on-site manufacturing facilities are being built to produce alkali and surfactant.
The second tertiary application of the alkaline-surfactant-polymer technology performed in the Xingshugang XF sandstone formation was initiated in August 1994. Estimated ultimate incremental oil recovery is 25% OOIP with the production as of May 1996 being 20.2% OOIP. The following statement was excerpted from page 35 of the "Oil and Gas Journal", Sept. 29, 1997 article on China:
"The three largest oil producing areas in the east had mixed results in 1996: Daqing maintained output, while Shengli's production fell, and Liaohe production rose somewhat.Daqing--China's largest producing complex--continued to produce 1.1 million b/d, or 35% of the national total in 1996.
In recent years, new technology that uses polymers to extract oil helped Daqing produce an additional 20,000 b/d and stabilized the field's output.During the next 5 years, China is scheduled to introduce tertiary recovery in its major eastern oil fields by applying polymer flooding and alkaline-surfactant polymer flooding.
The techniques are expected to increase production 140,000-200,000 b/d by 2000, partially offsetting the decline in other eastern oil fields.China hopes to maintain Daqing production at 1 million b/d until 2010--5 years beyond its previous estimate."
Production in 2001 due to polymer exceeded 175,000 b/d with expected incremental recovery of around 15% OOIP at total costs equal to that for waterflooding.3 In the 2005 SPE Advanced Technology Workshop on Chemical Flooding, China National Petroleum Company has published that more than a quarter of the daily production from Daqing (> 250,000 b/d) is attributed to the polymer flood. It also announced that it would expand the ASP projects into the full field.
1 Delamaide, E., Corlay, P., and Wang, D.: "Daqing Oil Field: The Success of Two Demonstration project Initiates First Extension of Polymer Injection in a Giant Oil Field," SPE 27819 presented at the SPE/COE Ninth Symposium on Improved Oil Recovery in Tulsa, Ok. April 17-20, 1994.
2 Gao, S. Li, H. Yang, Z., Pitts, M.J., Surkalo, H., and Wyatt, K.: "Alkaline-Surfactant-Polymer Demonstration project Performance of the West Central Saertu, Daqing Oil Field," SPE Reservoir Engineering, August 1996, pages 181-188.
3 Wang Demin, Sun Yingjie, Wan Tang Xuping: " Producing More than 75% of Daqing Oil Fields Production by IOR, What Experiences Have Been Leant?", SPE 77891, 2002
SURTEK, INC. 1511 Washington Ave Golden, Colorado 80401 Phone: (303) 278-0877 Email: surtek@surtek.com
