Research On Sand Control And Increasing Production Technique In The Unconsolidated Sand Reservoirs

Sand control is the most difficult issue faced by operation of the unconsolidated sand reservoirs. Traditional sand control techniques not only are ineffective to fine-silty sand control but also have great impact on the productivity of oil/gas wells. Fiber-resin coated sand control technique is put forward as a new technique for fine-silty sand control in the unconsolidated sand reservoirs, achieving both without sand production and oil/gas production stimulation purposes on the basis of new sand control theory of"clean pollution","stabling ambulatory sands","fixing sands","barring fine-silty sand congeries","protection reservoir"and"increase production". Based on the sand production mechanism analysis of Gudao Oil Field and Sebei Gas Field, which are two kinds of typical unconsolidated sand oil/gas reservoirs, comparative analysis of sand production affecting factors in oil/gas well is performed, and main affecting factors of unconsolidated sand gas reservoirs like Sebei Gas Field are found by grey correlation analysis of Sebei Gas Field's core sand production experiment data, and fiber-resin coated sand control technique and its sand control mechanism are brought forward in view of problems of grave fine-silty sand production, high shale content and short life of sand control. Fiber reinforcement mechanism is considered, tension stress and compression stress on single fiber are analyzed, and mechanical models of single fiber infinitesimal element are build, and then affecting factors of stress on cut fibres are analyzed, and theoretical forecast formula is amended on the basis of engineering constants of unidirectional parallel cut fibres reinforcement sand complex are ascertained by adopting semi-thumb rule, and after fiber distribution direction factor is inducted, consequently mechanics model of random orientation fiber reinforcement complex is educed. Considering operating technology of fiber-resin coated sand control technique, oil/gas wells inflow performance relationship forecasting models are build up after high-pressure pack and tip screen out (TSO) frac-packing fiber-resin coated sand control on the basis on oil/gas wells inflow performance relationship before sand control, and productivity evaluation of fiber-resin coated sand control wells are performed. Sand control in the condition of restricted wellbore needs better intensity performance of fiber-resin complex, and based on this background, the nano-material improved fiber-resin complex sand control technique is brought forward. The effective modified way is optimized, fiber-nanometer particles complexs are prepared by ultrasonic dispersing solution co-blended process, and nanometer material improvement mechanism is analyzed by IR and SEM methods. Fiber-resin coated sand control technique in the complicated well condition are developed, including fiber-complex sand control technique in the thermal production wells and low temperature fiber-sand conolidation technique, in order to improve fiber-complex sand control technique in the general well condition, which can solve the fine-silty sand control problem in the complicated well condition, such as the thermal production wells and low temperature wells, etc. Fiber-resin coated sand control technique has been successfully used in 28 wells'sand control in Gudao and Xianhe Oil Production Plant in Shengli Oilfield, Sebei Gas Field, and Xinjiang Oilfield. The technique is simple to operate, effective in sand control. High-pressure pack fiber-resin coated sand control in 5 production/injection wells have been performed and with 1:4.5 cost/benefit ratio, and TSO frac-packing fiber-resin coated sand control in 23 gas wells of Sebei Gas Field have been performed and with 1:17 or higher cost/benefit ratio, its productivity after treatment can increase to 2.15 times on average. Its period of validity is long. This technique provides strong technique support for the unconsolidated fine-silty sand reservoirs.