哈拉哈塘油田奥陶系碳酸盐岩油藏储集层泥砂产出机理

为厘清哈拉哈塘油田奥陶系油藏井壁失稳机理,重点分析了冲捞砂样的岩块和砂粒粒径及其矿物组分。研究区奥陶系碳酸盐岩储集层井壁失稳有2种形式：上部未封堵非生产层吐木休克组的井壁坍塌,即宏观失稳,形成井筒坍塌岩块;主力生产层流体携带的砂粒产出,即微观失稳,造成井筒泥砂复合堵塞,堵塞物主要包括裂缝充填物破碎和微凸体剥落产出的泥砂。灰色关联法井壁失稳主控因素分析结果表明,储集层埋深、井径、含水率、井眼方位等是影响井壁失稳的主要因素,通过优化井径、井眼方位以及工作制度,可以防控泥砂微粒产出。

Production Mechanism of Mud and Sand in Ordovician Carbonate Reservoirs in Halahatang Oilfield,Tarim Basin

In order to clarify the mechanism of wellbore instability in the Ordovician reservoirs of Halahatang oilfield, the rock, sand particle size and mineral composition of washed-out sand samples were mainly analyzed. It is found that wellbore instability in the Ordovician carbonate reservoirs in the study area occurs in two modes: (1) collapse of wellbore in the upper unplugged non-producing horizon (Tumuxiuke formation), that is, macroscopic instability, which results in collapsed rock blocks; and (2) production of sand carried by the fluids from key producing horizons, that is, microscopic instability, which causes the wellbore blockage by sand and mud generated from the cracking of fracture fillings and the exfoliated fine-grained components from micro-convex. The main controlling factors of wellbore instability were analyzed with the grey relational method, indicating that reservoir burial depth, wellbore diameter, water cut and wellbore azimuth are the main factors affecting wellbore instability. The wellbore diameter, wellbore azimuth and production system can be optimized to prevent and control the production of mud and sand.