The Optimizitaion Research On The Fracturing Fluid System Of Chang6Reservoir In Jiyuan Oilfield

Jiyuan region is located in the northwestern of Shan bei Slope Belt, across the TianhuanSync in Ordos Basin. Chang6reserves greatly, but it is typical of low porosity and lowpermeability oil fields, it’s characteristics such as poor reservoir physical properties, strongheterogeneity and needs to take fracturing measures in order to obtain a higher yield.Performance of the fracturing fluid affects the effect of fracturing directly, and it hasan important factor in the effects of stimulation effectiveness.First, the geological characteristics of Jiyuan Chang6were studied and analyzed, thestudy shows that there is a high level of clay mineral content by sensitivity to the fracturing inthis area, the highest contents of rock such as iron cement reservoirs in this area are kaolinite,chlorite,calcite, they content3.45%,3.89%,4.3%, and less heteroaryl group content. Thesensitivity can be obtained by evaluation of the experimental sensitivity of the reservoir area ischaracterized by: weak vecocity sensitivity, medium weak salt sensitivity, weak watersensitivity, moderate to strong acid sensitivity and no alkali sensitivity. Because reservoircontains the the minerals with sensitivity and has different degrees of sensitivity characteristics,so the direction of optimizing the fracturing fluid is low damage fracturing fluid system.Secondly, in the fracturing fluid system optimization principles to determine the premiseof Jiyuan by laboratory tests on the Chang6scene guanidine fracturing fluid system isoptimized to obtain a low concentration guanidine fracturing fluid system. The organic boroncrosslinked system by maintaining a good degree of cold adhesive, and has good heatresistance, shear resistance, and under the condition of70℃or80℃shear viscosity aremaintained at about100mPa·s in a hour, the content of the residue is345mg/L, the averagerate of core damage is24%,it has a better performance than the scene guanidine fracturingfluid system, and it can reduce the cost of fracturing effectively.For the issues of guanidine fracturing fluid, such as having too much residue content andthe high rate of reservoir damage, a hydrophobic associating polymer low damage fracturingfluid system is optimized. In recognition of the polymeric gel conditions, based on laboratory experiments by synthesizing the fracturing fluid into the glue adjuvants QJP-1, selected APSfor breaker and KCl for additive. The system residue content is78mg/L, core damage is only13%to15%, compared with guanidine fracturing fluid system can better reduce the damageand protect the reservoir.Finally, the two optimized fracturing fluid systems are used to complete in the livefracturing experiments in two wells of the Jiyuan Oilfield. It got smooth construction and goodflowback effect and achieved good yield.