Research On Fracturing Fluid Optimization And Field Application Technology

In association with the geologic features of SII and SIII layers in Xingnan Development Area and based on detail testing the physical property parameters of the core from the SII and SIII layers, this paper first estimates the adaptability of the fracturing fluid in use now,. The result suggests that the fracturing fluid system in use now can not agree with the geologic conditions of SII and SIII layers perfectly. The residue content is up to 530mg/l, which does harm to the matrix permeability of oil beds to a certain degree. The injury rate to SII oil bed is up to 26.21%, whereas to SIII oil bed is 25.84%. These numbers show the fracturing fluid system in use now needs further improving and optimizing in order to meet the demand of formation protection during the fracturing process.Therefore, on the basis of fluid system selection, we determine the composition and proportion of kinds of additives used in the fracturing fluid which is fit for the block and therefore a set of adaptable fracturing fluid systems has been formed. Laboratory experimental result suggests that the fracturing fluid system should be consisted of:Basic fracturing fluid: 0.40%guar gum+0.07% cleanup additive+0.05% demulsifier (SP-169)+1.0% clay stabilizer.Crosslinked fluid: 0.90% sodium borateGel breaker: 0.10% potassium persulfate.Testing shows the performance indexes of this system are all consonant with the demands of the petroleum industry standard. During the experiment we also find that the factors linking with additives which effect on the formation permeability are orderly: the residue content in fluid, the amount of clay stabilizer, gel breaker proportion. According to this find we can do better formation protection job during fracturing treatment process.By field applying, this achievement has been proved to be able to improve the effect of fracturing treatment in Xingnan Development Area. The successful rate of first fracturing reaches 100% on the 32 testing wells. On basis of almost the same fluid loss and width generation capacity, the rate of flowing back rises by 20% or more, compared with the conventional fracturing fluid. The intensity of fluid production and that of oil production rise by 0.18 and 0.12t/d.m respectively, the intensity of water injection rises by 0.16m3/d.m. Economical estimation proves us that the input-output ratio of this fracturing fluid optimization technology can reach to 1: 24.9,whereas the profit ratio of investment and the tax investment ratio can increase in times. Since there are more than 3000 wells to be fractured every year in Daqing Oil field, whereas the geologic conditions and the physical performance of the oil beds on the tertiary infill adjustment wells are similar to each other in Changhuan area, which provides broad application foreground for this technology, it is sure bring us good social and economical benefit in future.