Alkali/surfactant/poly mer (ASP) formulas were developed for the Daqing oil field, Peoples Republic of China, with two surfactants from the U.S. (Petrostep B-1OOand a blendofTRS-18 and TRS-40) and one Chinese surfactant (PS-DJ. Each ASP solution gave interracial tension (1~) values in the range of 1 x 10-3 mN/m. Rheologic studies with polyacrykurtide polymers indicate that solution viscosity decreases with alkali addition, as does the pseudoplasticity of the solution. Addition of surfactant to the alkali/polymer solution increases the solution viscosity with no slope change in the viscosity-vs.-shear-rate plot. Incremental oil recovery was higher than that with waterflood; 20% original oil in place (OOIP) for 0.2-PV ASP injection and 33?Z0OOIP for 0.3-PV ASP injection in Daqing core. Surfactant and alkali retention were both <1 mg/g sand. The positive results of this laboratory study provided a fluid formula for a pilot ASP flood in the Daqing oil field. p~,~K -1.0Mlb MO14. 1.2w196PS01. 1000m@LW720 2 J I o-1.0wn6t&OH *l.21mb PsD,

Summary After the success of polymer flooding in Daqing, two alkaline/surfactant/polymer (ASP) floods were conducted to increase oil recovery further, to study the feasibility of ASP flooding, and to provide technical and practical experience for expanding the ASP pilots. The crude oil of both pilots has a high paraffin content and low acid value. After extensive screening, an ASP system with very low surfactant concentration and wide range of ultralow interfacial tension (IFT) with any concentration change of the three components was determined for each pilot. Coreflooding and numerical simulation show more than 20% original-oil-in-place (OOIP) incremental recovery by ASP over waterflooding for both pilots. The ASP flood pilot tests are technically successful and, on the basis of preliminary evaluation, economically feasible; therefore, much larger-scale ASP-flooding field tests are planned in Daqing oil field in the near future. Introduction A polymer-flooding pilot test and a commercial field test have been conducted successfully in the Daqing oil field, and large-scale commercial application is now in process. To improve oil recovery and displacement efficiency further, surfactant/polymer- and micellar/polymer-flooding pilot tests have been conducted. All the tests achieved good technological results. Because of the high cost of use of large quantities of surfactants, this technology has not been expanded. ASP flooding can enlarge swept volume, improve the water/oil mobility ratio, and greatly improve displacement efficiency. Pilot tests of ASP flooding have been conducted, and good results achieved for high-acid-value crude oil; however, no pilot tests have been reported in reservoirs with low-acid-value crude oil. The acid value of crude oil in Daqing oil field is 0.1 mg/g KOH. We conducted ASP flooding research in laboratory and obtained good results. On the basis of the specific reservoir characteristics in north and south of Daqing oil field, two ASP-flood formulations were selected and pilot tests were conducted.

Summary A tertiary pilot application of the Alkaline-Surfactant-Polymer (ASP) process was initiated in September, 1994 in West Center Area of Daqing Oil Field. The pilot pattern consists of 4 inverted five-spot, including 4 injectors and 9 producers, as well as 2 observation wells encompassing an area of 90,000 m2 and with a pore volume of 203,300 m3. The target layer is Saertu II1-3 sandstone with average porosity of 26% and permeability of 1.426 m2. The crude oil viscosity is 11.5 mPa.S at reservoir temperature and the connate water salinity is 6,800 mg/L. The current pilot performance shows a pronounced response from Alkaline-Surfactant-Polymer injection. The average pilot area oil production rate increased from 36.7 m3/d to 91.5 m3/d, while water cut decreased from 82.7% to 59.7%. For the central well Po5, which is surrounded by injection wells, the oil production rate increased from 3.7 m3/d to 27.1 m3/d while water cut decreased from 87.9% to 45.8%. The numerical simulation results forecast that the oil recovery will be increased by 18.1% OOIP. Introduction The Daqing oil field is the largest field in the Peoples Republic of China. The pilot site is located on the west limb of the Saertu anticline. The reservoir slopes gently from east to west with an average depth of 814 m. The target layer in the pilot area, the Saertu II1-3 sandstone formation was deposited in a flood plain distributary environment. The sandbody is mainly composed of highly meandering distributary sandstone. The sandstone reservoir distribution is wide and thick, with high permeability and high inter-formational heterogeneity. The connate water salinity is relatively low, and fresh water is available. The reservoir characteristics, fluid properties, waterflood performance, and the performance of polymer flood pilot tests, indicated that the Daqing field was an ideal candidate for the Alkaline-Surfactant-Polymer process. Other papers have reported on ASP performance of field projects in the United States, but this paper reports on ASP effect at an advanced stage of waterflooding in the Daqing ASP pilot. History The Daqing field was discovered in 1959. Generalized water injection began in June of 1960 and separate layer injection began in January of 1965. The field was developed in a line drive pattern with rows of injectors 2,400 meters apart and spacing between wells within a row of 500 meters. Between rows of injectors are 3 rows of producing wells evenly spaced at 600 meters between rows. The oil production has been maintained at more than 160,000 m3/d since 1979 by this infill 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 pilots were performed beginning in 1987 with watercuts decreasing an average of 16% and oil rates increasing three-fold. These results indicated that mobility control polymer flooding could significantly improve oil recovery. As a result of these pilots, on-site polymer manufacturing facilities were built capable of producing 50,000 tons of polyacrylamide polymer per year. This facility began initial production in September of 1995. The Alkaline-Surfactant-Polymer process was identified as a means to further increase recovery and utilize the polymer made on site. The pilot area was originally developed beginning in December of 1987 for one of the polymer flood pilots. However, the polymer flood produced from intervals about 100 m deeper than the Alkaline-Surfactant-Polymer pilot. Fig. 1 shows the pilot area located between the well Zhong 5-8 and - Zhong 5-10 in the west central area of Daqing Field.

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Many ASP flooding method have been tested in Daqing oil field. After the success of polymer flooding in Daqing oil field, four alkaline- surfactant-polymer flooding pilot tests have been conducted in order to: increase oil recovery further and provide technical and practical experience for expanding the ASP pilot. From four ASP pilot test, the following conclusions can be made: ASP flooding pilot can form oil banks, greatly lower water cut, increase the oil production as well as the oil recovery. The incremental oil recovery was about 20% over water flooding. To further confirm the effect of large well spacing on EOR, three ASP field test with a large well spacing (200 to 250 m) have been tested in Daqing oil field. The commercial pilot tests result shows that the ASP flooding can increase recovery 20% more than water flooding. The paper collected 12 pilot test date of industrial surfactant flooding in China, It Has been evaluated that each pilot test successful or not cleanly. Also discussed problem. Emphasize indicated that design project of combination flood, surfactant kind, structure, slag design and size and a scale of production were developed key. Decreased cost were also important task. Alkaline-Surfactant-Polymer (ASP) flood processes have been increasingly applied in the oil fields due to their high ultimate oil recovery. However, a major technical challenge is how to significantly reduce the amount and the cost of chemicals used such that ASP floods can become cost-effective as well. Field applications show that the concentrations of alkali, surfactant and polymer remain relatively high in the produced fluids of ASP floods. Thus, successful reuse of these chemicals can substantially reduce the capital cost and the environmental impact. Also re-injection of the produced chemicals is conducted for further enhancing oil recovery. This paper have discuss problems of ASP flooding: Emulsions occurred in some producers of the larger well spacing field test, the test shows that by using a specific kind of de-emulsifier commonly used in the field, the emulsions in the produced fluid are not to be broken because adding hard alkali. This paper provides practice basis for the enlarging of ASP flooding..At present, most of ASP flooding are successful, But alkaline/com-oil carboxylates/polymer and foam/alkaline/surfactant/polymer flooding are not successful to be used to Daqing oilfield. The cost of chemicals (alkaline/surfactant/polymer) per barrel incremental oil is $11 to $15.The total cost of per barrel incremental oil is $15 to $30. The incremental recovery is 20% OOIP over water flooding.