| Block Jing-35 belongs to a small oil field of faulted block developed by Liaohe Petroleum Exploration Bureau. It was developed formally in May 1995. By December 1995, 97 various wells had been drilled, 82 oil wells had been put into production, and 61 wells had been opened in this block. The average fluid production of individual wells was 3.7 tons/day, the average oil production of individual wells was 3.1tons/day, and the comprehensive water cut is 14%. The oil production in that year was 69,855 tons, and its annual oil production rate was 0.72%. The reservoir of this block is characterized by fault rocks and low component maturity. Its lithology is mainly of hard arenaceous feldspathic sandstone and hybrid sandstone. Because of the rapid drop of oil production in this block, well stimulation has been employed since 1995. Eight kinds of EOR methods, solvent deplugging, ultrasonic deplugging, seismic oil production, electromagnetic heating, high energy gas accumulated energy hydraulic fracturing, CSS, microbe injection stimulation and slug flow driving, have been applied 60 wells times, and produced certain effect.To improve further the effect of well stimulation, a lot of experimental studies on the reservoir characteristics and fluid properties have been conducted for Block-35 under its specific conditions by way of analyzing its oil samples. Experiments carried out include: HTGC chart characteristic analysis, DSC chart characteristic analysis and viscosity-temperature curve characteristic analysis. In these experiments, the contents of high carbon number hydrocarbon compounds in high pour point oil were analyzed, and then the mathematical model for predicting wax precipitation in the reservoir was established against the impact rules of temperatures on wax precipitation. After screening of hydraulic fracturing fissure face improving/treating agent, experiment of treating agent's harm to proppant after hydraulic fracturing, and the experiment of fissure face treating agent properties, an effective treating agent formulation suitable for application under the stated reservoir conditions was developed. This treating agent can be used to eliminate the pollution and harm to propping fissures caused by hydraulic fracturing. Besides, with the application of it, the productivity of inefficient wells and low efficiency wells resulted from hydraulic fracturing pollution and harm can be improved greatly, and the effective period of hydraulic fracturing can be prolonged as well.The hydraulic fracturing face pollution improving technology and method for Block Jing-35 resulted from the study addressed in this paper can provide a theoretical basis for improving the development result of high pour point oil. |
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