吉木萨尔页岩油压裂返排液再利用技术

Reutilization Technology of Flowback Fluid from Jimusaer Shale Oil Fracturing

随着水平井体积压裂技术的推广与应用,压裂液用量越来越大,同时产生大量的返排液,返排液成分复杂,难以高效利用,直接排放会造成环境污染。为了缓解新疆油田压裂用水和降低压裂成本,开展了吉木萨尔页岩油压裂返排液再利用技术研究。对吉木萨尔页岩油区块返排液进行pH调节、硼离子屏蔽、杀菌的处理,然后利用处理后的返排液再次复配胍胶压裂液,通过考察所配制压裂液的溶胀性能、交联冻胶耐温耐剪切和破胶性能确定了利用返排液复配胍胶压裂液的最佳配方,并在J1井进行了现场试验。吉木萨尔页岩油返排液具有高含碱、高含硼、高含菌的特点,通过引入0.06%pH调节剂A、0.08%屏蔽剂C,0.10%高效杀菌剂BLX-1,将返排液的pH值调节至7.0,然后加入0.3%的交联剂XJ-3和0.045%的pH调节剂B。所配制的压裂液的交联时间控制在90~110 s,具有良好的耐温耐剪切性能,成胶后剪切120 min后黏度的依然大于200 mPa·s,且携砂性能良好,破胶液性能满足行业标准。利用页岩油压裂返排液连续混配再利用技术处理返排液4.5×10^(4)m^(3),且所配制的压裂液被成功应用于新疆油田页岩油J1井,为后期页岩油的高效环保开发奠定了基础。

With the development and application of volumetric hydraulic fracturing in horizontal wells,more and more fracturing fluid is being used and a lot of flowback fluid is produced.The composition of flowback fluid is complex,and It's hard to use efficiently.Direct discharge will cause environmental pollution.In order to relieve the shortage of water and reduce the fracturing cost in Xinjiang oilfield,the reutilization technology of flowback fluid from Jimusaer Shale oil fracturing was studied.After chemical treatment,such as pH adjustment,boron ion shielding and sterilization,the fracturing flowback fluid of Jimsar shale oil block was used to prepare guar gum fracturing fluid.Through investigating the swelling performance,the temperature and shear-resistance and the gel breaking performance,the best formula of guar gum fracturing fluid was determined.Then the field test was carried out at well J1.According to the characteristics of high alkali content,high boron content and high bacteria content of Jimsaer shale oil flowback fluid,the injection of 0.06%pH regulator A,0.08%shielding agent C and 0.10%efficient fungicide BLX-1 was carried out,the pH of the flowback fluid was adjusted to 7.0;then 0.3%cross-linking agent XJ-3 and 0.045%pH regulator B were added.the cross-linking time of the fracturing fluid prepared with the treated flowback fluid could be controlled within 90-110 s,and the viscosity of the fracturing fluid after gelation was still greater than 200 mPa·s after shearing for 120 min,indicating that the fracturing fluid had good performance of temperature tolerance,shearing resistance and proppant carrying capacity.Furthermore,it also possessed perfect gel breaking performance and could meet the industry standard.By using continuous mixing and reuse technology of shale oil fracturing fluid,4.5×104 m^(3 )fracturing flowback fluid was reused,moreover,the prepared fracturing fluid had successfully applied to shale oil well J1 of Xinjiang oilfield,which layed the groundwork for efficient and environmentally friendly development of shale oil in future.