【摘要】 简介了国外近期降低水基压裂液中植物胶类增稠剂浓度的三种技术:Nimerick等人的pH缓冲体系;锆交联羧甲基瓜尔胶压裂液;更高分子量的精加工瓜尔胶PEG硼交联压裂液。针对中原油田研发了90~140℃中高温低浓度HPG硼交联压裂液。在压裂液设计中采用浓度优化和泵注浓度由高到低变化两条原理,黏度低限为:在地层温度和170 1/s连续剪切90 min后前置液黏度≥150 mPa.s,携砂液黏度≥100 mPa.s。用0.45~0.90 mm的陶粒和压裂液破胶液测试,HPG浓度由0.5%减至0.4%时,15 h后的导流能力提高11.3%。得到了如下基本配方(HPG/有机硼交联剂/NaOH)。用于90~120℃的前置液:0.35%/0.35%/0.08%,携砂液:0.25%~0.30%/0.30%/0.08%;用于120~140℃的前置液:0.40%/0.45%/0.10%,携砂液:0.30%~0.35%/0.35%/0.10%。2002~2005年,该低浓度压裂液在中原油田应用于超过40井次的压裂,仅4井次未完成顶替。介绍了地温92℃和134.8℃的各一口油井的压裂工艺和良好效果。图6表1参6。更多还原

【Abstract】 Three ways of reducing polymer concentration in water base fracturing fluids,which are developed abroad recently,are summarized: pH buffering system of Nimerick et al.,Zr crosslinked CMG fluid;and borate crosslinked high molar mass PEG fluid. Aimed at oil reservoirs in Zhongyuan,a less concentrated borate crosslinked HPG fluid is developed for use at middle high temperatures 90—140℃.HPG concentration optimization and varying(decreasing) concentration fluid pumping schedule are taken as the 2 principles of fluid design and the viscosity minimum chosen is 150 mPa·s for pad fluids and 100 mPa·s for proppant carying fluid after shearing continuously in 90 minutes at 170 1/s and the aimed reservoir temperature.As measured on proppant packs of particle size 0.45—0.90 mm polluted by broken HPG/B fluid,reducing HPG concentration from 0.5% to 0.4% leads to 11.3% increase in conductivity of the packs.The basic recept of low polymer loading HPG/bororganics/NaOH fluid is as follows.0.35%/0.35%/0.08% fluid as pad and 0.25—0.30%/0.30%/0.08% fluid for proppant carying at 90—120℃;0.40%/0.45%/0.10% fluid as pad and 0.30—0.35%/0.35%/0.10% fluid for proppant carying at 120—140℃.In 2002—2005,this low polymer fluid was used in more than 40 wells in Zhongyuan and only 4 wells ceased out prematurely.The technology and the good results of fracturing operations in 2 production wells of reservoir temperature 92℃ and 134.8℃,respectively,are presented.更多还原