Oilfield Automatic Well Washing System

An automated control system was used in oil well thermal washing process, which consists of control circuit, flowmeter, electric control valve, and control sorftware. The thermal well washing are divided four working process every time, including warm-up washing, dissolve paraffin, remove paraffin, and washing. According to the theory of heating power well washing, well temperature test data, and the situation of paraffin deposition, the washing water flux and time are configured in every working process. The beginning and ending for oil well thermal washing was determined by outlet temperature T1 and inlet temperature T2 of washing water respectively. The thermal washing process was implemented by this mechanism in Da qing application oil field, in the condition of inlet temperature 85℃, thermal well washing pressure 3.1Mpa, outlet temperature 75℃, and a suit of corresponding thermal well washing parameters are configured. After 4 hours working, the outlet temperature rearched required, the paraffin was dissolved and removed below the 600 meters of oil grouand. The flux was intelligently dominated by the Fuzzy PID algorithm that can accurately adjust thermal well water flux. After thermal well washing by this system, washing water back flow can be restrained and energy was saved effectively, the working period has been shorten than before, and increase product 86.8ton/year per well. Experiment indicated that the system has many advantages of simply operating, high accuracy, well repeat, long using-life etc.