低渗低温水敏性浅层气藏压裂优化技术研究

低渗低温水敏性浅层气藏因其具有低温、水敏性强、成岩作用差、胶结疏松、水力裂缝形态不确定等一系列不利压裂改造与增产的因素，其改造技术与增产难度不亚于深井、超深井，故限制了其储量的高效动用。针对这些难题进行了技术攻关，形成了4项技术：弱交联、低温活化剂与超量破胶剂的低温储层快速破胶技术；有机盐与无机盐双元体系复合防膨技术；大粒径支撑剂尾追与高砂比施工的防支撑剂嵌入高导流技术；浅层、疏松性气藏压裂全程保护与压后放喷排液管理技术。吐哈鄯勒浅层气藏勒9-1井应用该技术进行先导性压裂试验取得成功，加砂53.1 m³,最高砂液比60%，平均砂液比39.2%。压后立即用3 mm油嘴控制放喷、排液50.0 m³取得的返排液样品，测试其破胶水化液粘度为5.1 mPa·s。压后气产量从压前4633 m³/d提高到稳定的2.75×10⁴m³/d，无阻流量5.76×10⁴m³/d。该井压裂的成功，说明了低渗低温水敏性浅层气层压裂优化技术的适用性，并使鄯勒浅层气藏的低渗难动用储量有效动用有了技术保证。

RESEARCH ON FRACTURING OPTIMIZATION FOR SHALLOW GAS RESERVOIRS WITH LOW PERMEABILITY, LOW TEMPERATURE, AND WATER SENSITIVITY

Shallow reservoirs with low permeability, low temperature, and water sensitivity , characterized by various factors that have an adverse effect on fracturing and stimulation, such as low temperature, strong water sensitivity, poor diagenesis, loose consolidation, and uncertain geometry of hydraulic fractures, are no less in the difficulties of stimulation operation in this kind of reservoirs than that in deep or ultra deep wells, thus highly efficient producing of their reserves are limited. In view of these problems, researches were carried out and 4 techniques have been developed which are rapid viscosity break in low temperature reservoirs with weak cross linking, low temperature activator and extra amount of gel breaker; combined anti swelling with binary system containing organic and inorganic salts; preventing proppant embedment to form high fluid conductivity through large diameter proppant tailing and high sand concentration operation ;and whole process protection during fracturing and blowing off after fracturing operation in shallow, loose gas reservoirs. These technologies have been successfully used in the pilot fracturing of the well LE 9-1 in the Shanle shallow reservoir in Tuha with sand of 53.1 m3, maximum sand fluid ratio of 60% and average sand fluid ratio of 39.2%. The blowing off was done by a 3 mm choke immediately and the fluid delivery was 50.0 m3 after the fracturing. Took the fluid sample to test the viscosity of the hydration formed by viscosity break, it is 5.1 mPa·s. the production has been increased from 4633 m3/d before fracturing to a steady production of 2.75×104m3/d with an absolute open flow of 5.76×104m3/d. The successful fracturing of this well shows the applicability of fracturing optimization technology for shallow gas reservoirs with low permeability, low temperature, and water sensitivity, which has provided a technical support to produce the shallow, low permeability gas reserves in Shanle that is hard to develop.