埕东油田东区二次开发潜力及措施探讨

Discussion on potential and treatment of redevelopment,east block,Chengdong Oilfield

埕东油田东区是一个开发了35a,含水率持续5a接近98%的"濒临废弃"油田,但是密闭取心显示层间、层内仍然富集较多剩余油。针对非主力层及注采对应较差的主力层水淹较弱、剩余油饱和度较高的特点,提出了进行层系重组可行性研究以及减小层间差异的整体调整措施;对薄层非主力层及快速尖灭的厚层河道边缘可以利用水平井进行局部挖潜;对分段水洗明显的复合正韵律主力层,建议进行化学驱现场试验,室内物理模拟实验结果表明,二元复合驱技术的驱油效率最高,预交联驱技术的波及系数最高;夹层对层内油水运移有一定影响,夹层厚度越大、分布越稳定对剩余油分布影响越明显,利用微电位、微梯度变化程度与夹层厚度呈正相关性的特点,可以定量计算夹层的厚度。

The east block of Chengdong Oilfield,which has been developed for 35 years with water cut up to 98% in 5 consecutive years and is nearly depleted,is contradicted by rich remaining oil trapped in the inner-layer and interlayer of reservoir as revealed by the sealing core.In response to the situation that non-major layers and the major layers inferior in correspondence of injection are less flooded and of high remaining oil abundance.the general treatment measure to study the layer reorganization feasibility and decrease the interlayer difference is proposed.Horizontal wells may be utilized to the production of non-major layer and rapidly thinning thick channel edge.Field chemical flooding experiment is suggested for the composite thinning-upward major layers,which are layered flooded seriously.The lab physical simulation and experiment illustrated that the displacement effi-ciency of binary composite flooding technique is the highest,and the sweeping coefficient of pre-link flooding technique is the largest.The interlayer is of some influence on the oil and water migration in reservoirs:the thicker of the interlayer and more stable of the distribution.the more influence on the distribution of remaining oil.The interlayer thickness may be calculated based on the correlation between interlayer thickness and the variation of RMN and RML.