肯基亚克盐上油田侏罗系潟湖-浅水三角洲沉积特征

Lagoon-shallow-water Deltas Deposition Characteristics of the Middle Jurassic in Up-salt Kenjiyake Oilfield

哈萨克斯坦肯基亚克盐上油田侏罗系为一套陆源碎屑沉积,目前该区沉积相类型存在争议、砂体特征不清楚,生产矛盾突出。因此,在高密度井网条件下（50~100 m井距）,通过岩心观察、粒度分析、测井解释,从大地构造、古气候、湖泊类型等方面,对肯基亚克盐上油田侏罗系中统沉积特征进行研究。研究表明：侏罗系中统沉积时期为地势平坦、温暖潮湿的浅水潟湖环境;其发育粒度细、分选磨圆好、泥岩呈暗色并含有生物碎片层的浅水三角洲相和澙湖相沉积,其砂体呈现出＂星状＂、＂树枝状＂、＂网-带状＂等特征;星状砂体主要为湖平面上升时期,波浪作用的结果;树枝状砂体主要为河控砂体;网-带状砂体主要为河流和湖浪共同作用的结果。该区共识别出三角洲平原、三角洲前缘、前三角洲、浅湖4个亚相以及水上分支河道、河漫、水下分支河道等10个微相;分析了各微相和砂体的平面展布特征及其影响因素,这为开发、注水、气驱、聚驱方式的优化提供了地质依据。

The up-salt Kenjiyake oilfield of Kazakhstan in the Middle Jurassic depositional groups consist of clastic deposits. There is some controversy to the types of sedimentary facies in the area. And the sand body char- acteristics is unclear, it is facing an increasing contradiction between water or gas injection well and oil well. Therefore, under the condition of dense well pattern （50 - 100 m well spacing） , through core observation, from the aspects such as tectonics, paleoclimate, lake type, sedimentary characteristics were studied in detail of the Middle Jurassic in up-salt Kenjiyake oilfield. Research shows that depositional environment of the Middle Jurassic in up-salt Kenjiyake Oilfield is a lagoon, it＇ s flat terrain, warm, humid and a lagoon--shallow-water deltas system, one of its features are fine granularity, good sorting and rounding, dark mudstones, containing fragments of shells. The distribution of sand bodies like ＂stellate＂, ＂arborization＂, ＂net-banded＂ and other morphology. The rising of the relative lake-level and wave action control the forming and distribution of stellate sand body. The river largely controls the arborization sand body morphology. The river and wave action controls net-banded sand body morpholo- gy. Results facise of this areas are delta front, delta plain, frontal delta, including 10 kinds of microfacies： ditribu- tary channel, alluvial marsh sub-water distributary channel, etc. On the basis of it, the plane distribution features of sand bodies and the related factors are elaborated. This provide geological theory basis for development method, water flooding, polymer flooding and gas drive, etc.