Research On Reservoir Protection Technology Of Horizontal Well In Shallow Layer Of Jilin Oilfield

Most of target stratum of Songnan shallow layer in Jilin oilfield is the low permeability and low porosity reservoir. The reservoir condition of permeability and porosity is very poor. The size of pore throat is tiny. In the process of drilling, the damage degree of water sensitive and water block is serious. And the efficency of exploitation and development is low. In addition, the salinity of formation water varies between 10000 ppm and 60000 ppm. It’s difficult to protect the reservoir. The performance of KC L polymer drilling fluid system should be improved, such as water sensitivity resistance and water block resistance. First, we analyze the mineral component, predict the formation sensitivity and evaluate the main damage mechanism of the shallow layer in Jilin oilfield. We determine that the main damage is water sensitivity and water block. Secondly, according to the fact of shallow layer horizontal well in Jilin oilfield, we proposed the reservoir protection measure to resist the water sensitivity and water block. Thirdly, in order to minimize the damage degree, we composite new water block resistant agent FCS and broadspectrum temporary blocking agent GPJ. The indoor experiment results indicate that the FCS can reduce interfacial tension between water and oil effectively. And GPJ can effectively inhibit formation of hydrate swelling. We formed the compatible KCL drilling fluid system, which has the function of water sensitivity resistance and water block resistance. The recovery permeability can reach 93.94% in the indoor dynamic contaminate experiment. Finally, we established the reservoir protection technology of horizontal well in Jilin oilfield, and evaluation methodology and model of reservoir damage. The model includes quantitative evaluation model of water block damage, experiment evaluation of water block and CST diagnostic of water sensitivity damage. The results of experiment prove that this drilling fluid system can reduce water sensitivity and water block damage effectively.