塔河油田缝洞型油藏高产油井见水预警评价技术

A water breakthrough warning system of high-yield wells in fractured-vuggy reservoirs in Tahe Oilfield

利用塔河油田已见水高产井资料,总结其见水预警参数,研究水淹预警机理,并结合油井见水影响因素,建立水淹预警机制。塔河油田奥陶系溶洞型和裂缝-孔洞型油藏开采过程中,底水经历水侵前—成锥期—托锥期—突破期4个阶段的变化。托锥后期,水侵会使溶洞系统的压力发生震荡,这种震荡对井底流压有一定的影响;根据节点分析思想,井底流压变化时,井口油压也变化,在生产指标上出现流压、油压、套压或产量的异常信号。根据影响油井见水的地质因素、工程因素、生产管理因素及油井见水前异常信号,总结出缝洞型油藏油井见水风险分级评价的31项指标,形成了高产井预警技术。经塔河油田奥陶系碳酸盐岩油藏146口未见水高产井验证,预警评价技术预警效果好,延长了油井无水采油期。

A water-out warning system is set up by using water breakthrough data of high yield wells, summing up warning parameters of water-out, and combining with influencing factors of water-out. During the development of Ordovician karst-cave and fracture-vug reservoirs in the Tahe Oilfield, bottom water goes through four stages： prior water invasion, cone period, supporting cone period and breakthrough period. In the late period of the supporting cone, bottom water leads to pressure oscillation in the dissolved cave system, which affects the bottom-hole pressure to some extent. According to the nodal analysis theory, the change of bottom-hole pressure will lead to changes of wellhead pressure, and abnormal signals such as abnormal bottom-hole flowing pressure, tubing pressure, casing pressure, or output. According to geological, engineering, production management factors, and abnormal signals before water-out, 31 indices for water-out risk evaluation are summed up, and early water breakthrough warning technique for high-yield wells is established. Application of the technique to 146 no-water high-yield wells shows the warning technique works well and extends the water free production period.