南苏丹ANANAS区块部分大尺寸套管井采用土酸和桥塞酸化工艺解堵增产,但土酸反应过快,桥塞管柱操作复杂且存在酸液泄漏风险,因此亟需研制大尺寸套管井多级酸化技术.通过设计小截面定活塞、分离进液口与注酸口、选定T型密封圈密封注酸口,研制了新型注酸器;通过酸液缓蚀性能评价、络合性能测试及配伍性试验,优选出一种适用于该区块储层的HV缓速酸液体系.室内试验表明:新型注酸器开启压力高达8 MPa以上,能使?147 mm封隔器稳定坐封;理论上单趟管柱可酸化15段且可用于套管验漏;HV缓速酸液体系缓蚀性能优于常规土酸体系,能够有效络合储层金属离子,抑制二次沉淀产生,与多种添加剂配伍性能良好.该技术可用于大尺寸套管井3段以上酸化增产,采用HV缓速酸体系能有效扩大酸液作用距离,解除近井地带伤害,措施效果显著,建议今后考虑转向酸压,以进一步提高储层改造程度.

Currently, there are about 30,000 damaged-casing wells in Daqing Oilfield in China and nearly 10

大庆油田累计套损井近万口,为了动用这些压裂程度低、剩余油相对富集的潜力井,开展了多级大规模压裂工艺研究.通过有限元软件分析胶筒肩部角度、长度与应力之间的关系,并通过油浸实验验证了胶筒在大形变下的耐温承压性能;应用自编软件优化调整关键部件尺寸,设计了工艺配套工具.最终确定了小直径封隔器胶筒肩部角度50°,长度550 mm;小直径喷砂器能够针对套管内径大于 ?104 mm的套损井进行施工,工艺覆盖率提升至70％;新型锚定工具可确保工具通过套损点并使管柱稳定;双功能防喷封隔器能够实现目的层封隔及油管防喷.现场试验结果表明,该工艺及配套工具能够用于套损井压裂,单趟管柱可压裂5层,砂量289 m3,初步实现了套损井大规模压裂施工.

After Daqing Oilfield entered its late development stage, peripheral Fuyang Formation having low permeability has become the primary target for oil production in Daqing Oilfield. Large-scale multi-stage fracturing techniques have been deployed to enhance productivity of individual wells to develop hardly reachable reserves. Currently, fracturing strings with staged slide-sleeve structures are used extensively in Daqing Oilfield. However the decrease of slide sleeves in diameter usually results in chocking energy loss around joints, potentially restricting discharging capacity. To eliminate energy loss related to pipe strings with reduced diameters, full-sized multi-stage diverting packers for fracturing stimulation have been developed, and by calculating chocking loss, proper diam-eters can be determined to achieve the maximum discharging capacity. ABAQUS finite-element software was applied to simulate and analyze contact stress among rubber barrel and casing to achieve desirable sealing performances. Laboratory oil immersion experiments confirmed the temperature resistance, pressure resistance and fatigue performances of these packers. By now they have been deployed in 4 wells, delivering a success rate of 100%. This indicates that the innovative full-sized fracturing technology is practicable for large-scale fracturing stimulation with high capacity and efficiency.

Hailar basin,with its property of low porosity and permeability,is complex fault block reservoir which is hardly recovered because of heterogeneity.Regular frac technology with ineffec-tive stimulation cannot meet the requirements of HPHT and high sand volume.To realize large-scale fracturing and to increase the well production and efficiency,by pressure calculation,flow state simulation and experiment indoor and site application,vertical well multi-stage fracturing without moving string in Hailar basin is developed.It has realized big scale fracturing with big sand volume and rate.Matched tools including big diameter packer and relevant rubber element, big diameter hydraulic anchor have been developed.The technology has been applied in 30 wells with obvious effect under the big sand volume and rate fracturing.