大庆萨南油田特高含水期水驱注采结构优化调整方法

Optimizing and adjusting methods of the waterflooding injection-production structure at extra-high watercut stage for Daqing Sanan Oilfield

大庆萨南油田进入特高含水期以来,其油层典型多层非均质和较大渗透率级差导致的不同井网、油层动用不均衡等开发矛盾进一步加剧,严重影响开发效果。根据油藏工程基本原理,在研究分类井网含水率上升规律的基础上,以全区含水率最低、采收率最高为优化目标,建立了分类井网产液量分配比例优化数学模型。根据数学模型计算结果,得出分类井网优化注水采液结构调整原则,以此为理论依据,结合矿场实际,设计了萨南油田X区块分类井网注水产液结构调整方案,预测了各方案结构调整效果。矿场实践结果表明:方案实施后该区块取得较好的增油降水效果,调整前后井区日增油量14 t,含水率下降0.04百分点,减缓区块自然递减率1.4百分点。研究成果为整个油田全面实施注水产液结构调整举措提供了重要的理论和实践依据。

Since Daqing Sanan Oilfield entered extra-high watercut stage,the development contradictions such as different well patterns,uneven reservoir development and so on are further aggravated,which caused by the typical multilayer heterogeneity and large permeability differential of the oil reservoir,has severely affected the development effects.On the basis of the fundamental principle of the reservoir engineering and the increasing law of the water cut for the classified well pattern,the optimized mathematical model of the production liquid distribution proportion in the classified well pattern was established to realize the lowest watercut and the highest recovery in the whole area.According to the calculated results of the mathematical model,the principles of optimizing the structural adjustments of the water injection and fluid production in the classified well pattern are established.On the basis of this theory and combined with the actual field situation,the adjusting schemes of the water injection and liquid production structures for the classified well pattern in Block X of Sanan Oilfield were designed and the effects of the structural adjustments of each scheme were predicted.The results of the field practice show that this block has achieved much better results of increasing the oil production and decreasing the water cut after this program was implemented,which the average daily oil production increases by 14 tons,the water cut decreases by 0.04 percentage,and the natural declining rate retards by 1.4 percentage.The research results provide the important theoretical and practical evidances for the whole oilfield to carry out the major measures of the water injection and liquid production structural adjustments in an all-round way.