桩74断块南区重复压裂技术

A STUDY ON REFR REFRACTURING TECHNIQUE IN SOUTH ZHUANG 74 BLOCK ACTA

油井压裂后，随着开发生产的延续，裂缝由于受污染、堵塞、挤压等因素的影响，其导流能力逐渐降低，从而失去压裂的增油效果，在油层能量和储量没有得到充分发挥的情况下，需进行重复压裂。根据胜利五号桩油田桩７４块南区特低渗、高凝固点、高温异常、超深、且第一次压裂后初产高、递减快的油藏特点，对８口经过第一次压裂井的有效渗透率、岩石杨氏模量、泊松比、地应力剖面、地层能量和剩余可采储量进行了客观的评价，认为具备重复压裂的条件。用ＤＳＴ试井、水力压裂模拟和油藏数值模拟方法计算了原裂缝的几何形态，评价了导流能力。确定了桩７４块南区重复压裂选井选层的原则，筛选了重复压裂的压裂液和支撑剂，设计出了重复压裂方案，并优选出最优裂缝支撑半长在１１０～１２９ｍ之间。按设计方案施工，取得了良好的增油效果，裂缝导流能力较第一次压裂提高了４倍，生产１３３ｄ后，净收益达到１６６．９万元。

he effect to increase oil production of fracturing will lost with the reducing of fracture inflow ability because of pollution,blockage etc.after a period in a well.Refracture should be carried on under the condition that a lot of formation energy and reserve has been remained.In this paper,the effective permeability,Yong's ratio,formation stress profile,energy and remained reserve have been evaluated to 8 wells in south Zhuang 74 block in Shengli Wu Haozhuang oil field according to the characteristics of lowpermeability,high solidification point,temprature and depth,as well as fast decreasing production after a high initial value in first fracturing.It is considered that the wells have the condition to be refractured.The geometric configuration and flowing ability of the fracture after first fracturing has been caculated and evaluated by using DST well test,fracturing and reservoir simulation.The plan has been given on the principles and results to chose wells,formations,fracturing fluids and proppants.The optimium fracture half length is 110-120m according to this study.The plan has reached good results that fracture flow capacity increases 4 times and the net income is 1,669,000 Yuan 133 days after the fracture plan being finished.