Hydraulic Fracturing in Low Temperature Horizontal Wells

Abstract

For shallow burying, the temperature is less than 30℃ and low pressure in Putaohua formations in Chaoyanggou area in Daqing oilfield. Eight horizontal wells have been drilled in the area and need hydraulic fracturing to improve the oil production. Two challenges have to be faced. One is how to rapidly completely breaking for gel at the low temperature and improve the flow-back ratio of fracturing fluid after the fracturing, to reduce the formation damage. It is difficult to gel breaking quickly with conventional breaker in the conventional hydraulic fluid system under the super low temperature. Another one is how to improve the production of fracturing in the horizontal wells. According to the characteristic of the horizontal wells in the low temperature, low pressure reservoir, some new technologies have been used in the 8 wells fracturing jobs, such as a new type low temperature breaker, a new type of cleanup, mechanical isolation staged fracturing . In this paper, we provide details about these new hydraulic fracturing techniques applied in the horizontal wells. The Application in eight wells just as the following aspects: According to the study in the lab, a new type of fracturing fluid system has been used to suit the low temperature. At 30℃, after 4h later, the fracturing fluid was broken, and the viscosity of fracturing fluid is 3.5mPa.s. Mechanical isolation and staged fracturing with two packers is used in the horizontal wells with high efficient treatment about 4 to 6 stages per day to improve the oil production. Base on above all, we get the good result of oil production on the 8 horizontal wells, about 5.2 times higher than that on vertical fracturing wells at the same area. In this paper, we provide details about these new hydraulic fracturing techniques applied in the horizontal wells. These new technologies of fracturing provide an effective method for the horizontal wells in low temperature reservoirs in Daqing oil field.