鄂尔多斯盆地南泥湾异常低压油藏成因及异常低压对油藏开发的影响

Genesis of abnormal low pressure reservoir of Nanniwan Oilfield in Ordos Basin and influence of abnormal low pressure on the development of the reservoir

根据南泥湾油田的压力测试资料,分析了油藏异常低压的特征及成因,认为抬升剥蚀、孔隙度反弹、温度降低改造骨架和流体的收缩以及油气散失是主要原因.异常低压油藏在生产中表现出的主要特征是自然产能低,产量递减快,一旦产生渗透率应力敏感,很难恢复.对比分析了超前注水和正常注水开发的效果,超前注水井组初期平均单井日产油量是正常注水采油井的2.86倍,前者累计产量是后者的1.7倍.超前注水开发方式能够克服异常低压的不足,这一措施在生产中已推广应用,效果良好.

According to the pressure test data of Nanniwan Oilfield,the genesis and the characteristics the abnormal low-pressure are analyzed,and it is held that,the uplift and erosion,the porosity rebound,the shrinkage of skeleton and fluid caused by temperature decreasing,and oil and gas dissipation are the main reasons to form the abnormally low pressure reservoir,and the main features of the abnormal low pressure reservoir in the production process are low natural productivity and the sharp decline of output,once the stress sensitivity of permeability occurs,its restoration is very difficult. The development results of advanced water injection and normal water injection are compared and analyzed,it is shown that,the average single-well daily oil production of the advanced water injection wells is 2. 86 times as great as that of the normal water injection wells,and the cumulative oil production of the former is 1. 7 times as great as that of the latter. Advanced water injection development can overcome the shortcomings of abnormal low pressure,and this measures have been applied to the production and a good result is obtained.