Paraffin is mainly composed of n?alkanes, small amounts of i?alkanes, cycloalkanes, aromatic hydrocarbons and trace amounts of S,N,O compounds. Under the action of ultraviolet light and heat, those compounds containing elements S,N,O,aromatic and unstable elements of alkene aromatic can be oxidated,resulting in a darker color and lower paraffin light stability.In order to explore the reasons for the deterioration of the paraffin light stability,the effects of internal factors such as nitrates,sulfides and oil content on the paraffin light stability were investigated.Orthogonal experiments were carried out to investigate the effects of ultraviolet absorbers,hindered amine light stabilizers,antioxidants and its compounding agent on the improvement of the paraffin light stability.The results showed that the best paraffin light stability was achieved when the additive amounts of UV absorbers, hindered amine light stabilizers and antioxidants in the compound were 300 μg/g, 300 μg/g and 300 μg/g, respectively.

Given the deep burial depth,high temperature and high pressure, significant heterogeneity of the deep gas reservoirs in the southern margin of the Junggar Basin,the temporary plugging and diverting stimulation technology with stratification and segmentation was used to achieve efficient stimulation and improve the producing degree of those reservoirs.The plugging of fractures and perforations by temporary plugging agents under the high temperature of 140~180 ℃ was experimentally investigated,and the degradation rates and pressure?bearing capacities of five temporary plugging materials were evaluated respectively.The results show that the commonly used temporary plugging materials will soften under a high temperature and tend to flow with the carrying fluid under the displacement pressure difference, resulting in a decreased pressure?bearing capacity of the temporary plugging section and the loss of plugging effect. A temporary plugging material with a pressure?bearing capacity of 30.00 MPa at 180 ℃ was selected, and its field application results showed that the temporary plugging improved production significantly.