塔河油田三叠系石炭系井眼失稳机理及控制技术

Wellbore instability and control technologies in the Triassic system and Carboniferous system in Tahe Oilfield

针对塔河油田三叠系石炭系易扩径的特点,进行了现场岩心表观特征分析、岩心粘土矿物分析、毛细管吸附膨胀和CST分散实验、岩心浸泡评价等系列研究,找出了地层扩径的机理原因;提出了塔河三叠系石炭系防扩径对策。防扩径对策为:①建立了地层孔隙压力和坍塌压力剖面,确定了现场钻井液密度;②利用屏蔽封堵技术,在微裂隙发育的泥页岩井壁形成类似于橡皮套的屏蔽层,提高了地层的力学防塌能力;③在原聚磺钻井液基础上通过硅络合醇提高钻井液的化学防塌能力,滚动回收率从原来的68％提高到了88％。现场应用表明:三叠系井径平均扩大率为5.82％,石炭系为5.43％,井径质量达到了优质标准;硅络合醇聚磺屏蔽封堵钻井液技术不仅有效地解决了TK634井三叠系石炭系地层扩径问题,而且材料成本与原聚磺钻井液相当,具有很好的应用推广前景。

In accordance with the hole enlargement characteristic in the Triassic system and Carboniferous system in Tahe Oilfield, a series of researches were conducted, such as the on-site core behavior analysis, core clay mineral analysis, capillary adsorption inflation and CST dispersing test, and core soaking evaluation, etc. , to determine the causes and mechanisms of hole enlargement. The hole enlargement methods were presented, and the corresponding measures included; 1. establishing the formation pore pressure and collapsing pressure profile and determining the field drilling fluid density; 2. using temporary shield plug- ging technology to form a shielding layer on the micro-fracture developed borewall, thus improve its dynamic sloughing control; 3. adding silicon complexing alcohol in the polysulfonated drilling fluid to improve its chemistry sloughing control, and improving the rolling recovery rate from the original 68% to 88%. Field using showed that the hole enlargement rates in the Triassic system and Carboniferous system are 5. 82% and 5. 43% respectively, and regular borehole was drilled. This drilling fluid technology effectively solved the hole enlargement in the Triassic system and Carboniferous system when drilling Well TK634. Its material cost was almost the same with the original polysulfonated drilling fluid, thus could be widely used in the drilling operations.