哈萨克斯坦NB油田白垩系储层特征及主控因素分析

Analysis of Cretaceous Reservoir Main Controlling Factors in Kazakhstan’s NB Oilfield

为明确哈萨克斯坦NB油田白垩系储层和油气藏的主控因素,促进油田构造低部位的滚动勘探开发进程,对储层岩石学特征、物性特征、沉积微相和储层主控因素进行研究分析。结果表明:白垩系储层岩石类型以岩屑质长石砂岩、长石砂岩及长石质岩屑砂岩为主,储层物性较好,以中高孔—中高渗储层为主。物源主要来自北偏东方向,沉积相为三角洲前缘亚相,发育水下分支河道、河道间、前缘席状砂等沉积微相,储层物性主要受控于沉积微相,物性高值区与水下分支河道砂体分布范围基本一致。明确了白垩系沉积微相类型和有利储集体分布特征,有效指导了NB油田滚动勘探开发部署。

The cretaceous stratified oil-gas reservoir in Kazakhstan’s NB oilfield was developed with complex oil-gas-water relations.In order to clarify the main controlling factors of the reservoir and oil-gas reservoir and promote rolling exploration and development process of the low structure of the oilfield,the petrological,physical characteristics,sedimentary microfacies and the main controlling factors of reservoir were studied and analyzed.The results showed that cretaceous reservoir rocks were mainly composed of lithic arkosic sandstones,arkosic sandstones and feldspathic lithoclastic sandstones.The reservoir physical property was satisfactory which had medium-high porosity and medium-high permeability.The source was mainly from the north to the east direction;the sedimentary facies were the delta front subfacies;and sedimentary microfacies were deveolped,such as subchannel,interchannel,leading edge sheet sand,etc.The reservoir physical property was mainly controlled by the sedimentary microfacies,and the high physical value area was basically consistent with the distribution range of the subchannel sand body of the underwater branch.Through the study,the sedimentary microfacies of cretaceous and the distribution characteristics of favorable reservoirs were clarified,which effectively guided the rolling exploration and development deployment of NB oilfield.