低渗致密油藏适度温和注水技术研究与矿场实践

为解决低渗致密油藏注水过程中，水相沿着裂缝水窜水淹、基质原油难采出、水驱采收率低等技术难题，以鄂尔多斯盆地延长组长₆储层为研究对象，开展驱替速度对水驱采收率影响的驱替实验并进行核磁测试分析，建立考虑毛管力的非稳态油-水两相水驱前缘推进数学模型，形成适度温和注水强度优化图版。结果表明，水驱油过程存在最佳驱替速度使得水驱采收率最大，实验中最佳驱替速度为0.06~0.08 mL/min。以延长油田ZC区块为例，调整注水强度为0.85~1.20 m³/（d·m），采油泵沉没度控制在100~150 m，技术应用后水驱采收率从20%提高到24%。适度温和注水技术对低渗致密油藏提高采收率效果显著，研究成果为类似油藏高效注水开发提供了借鉴。

Research and Field Practice of Moderate Mild Water Injection Technology in Low Permeability Tight Reservoir

In order to solve the technical problems of water phased channeling and flooding with fracture water, difficulties in recovery of matrix crude oil and low water drive recovery in ultra-low permeability tight reservoirs during water injection. In order to explore the effect of displacement rate on water drives recovery, we carry out the displacement experiment taking Chang-6 Reservoir of Ordos Basin as the research object. Then the NMR test results are analyzed, finally, the unsteady oilwater two-phase water flooding front propulsion mathematical model considering capillary force is established to form the policy method of moderate water injection technology. The results show that there is an optimal displacement rate in the process of water flooding, which makes the water flooding recovery maximum. The best displacement rate in the experiment is 0.06~0.08 mL/min. Taking the ZC Block of Yanchang Oil Production Plant as an example, moderate technical policies is adopted to control the water injection intensity in the block of 0.85~1.20 m³/(d·m), and the submergence of the oil pump is controlled at 100~150 m. After the application of the technology, production data show that the water flooding recovery is increased from 20% to 24%. Moderate mild water injection technology has a significant effect on EOR of low-permeability tight reservoir. The research results provide a reference for similar reservoirs in the process of high-efficiency water injection development.