云南江城钾盐基准井钻进工艺分析

云南江城钾盐基准井位于思茅凹陷东区南部向斜翼部两条断层交汇处,构造相对发育,岩石破碎。其施工目的主要目的是通过取心钻进获取＂中、新生代＂含盐建造完整的地层序列,建立一个可供找钾参照的＂标杆地层柱＂。其施工的难点是上部地层以石英砂岩为主,与泥岩互层,泥岩较软、易水化、难取心;砂岩坚硬、研磨性强;下部地层主要以泥岩为主夹薄层砂岩,泥岩致密硬脆,在孔底呈弹塑性,可钻性极差。通过选择合理的钻井设备,优化钻具组合,制订切合实际的钻进参数,采用镁基盐水钻井液,进行川-74取心筒传统取心和绳索取心钻进,获得了盐矿心无溶蚀现象,井眼轨迹和岩心采取率均达到设计要求的较好效果。

Potassium Salt Stratigraphic Well Drilling Technology Analysis in Jiangcheng,Yunnan

The potassium salt stratigraphic well in Jiangcheng, Yunnan is situated at the junction of two faults within a syncline limb in south part of eastern Simao depression where structures are relatively developed, rocks fragmented. The main purpose of the well is through coring to obtain integrated stratigraphic sequence of Mesozoic and Cenozoic salt-bearing formation, establish a＂benchmark stratigraphic column＂for potassium salt prospecting reference. The nodi in drilling have upper part strata are mainly quartzose sandstone alternated with mudstone, the mudstone is softer, easy to be degraded in water and hard to coring, while the sandstone is hard and strong abrasive resistance; lower part strata are mainly mudstone intercalated with thin sandstone, mudstone is compact, hard and brittle presents elastoplasticity at borehole bottom, thus poor drillability. Through reasonable drilling equipment choosing to optimize drilling tool assembly, practicable drilling parameters stipulation, magnesium based salt water drilling fluid using, carried out well Chuan-74 traditional core barrel and wire-line core drilling, come true of acquired salt cores without corrosion phenomenon, wellbore locus and core recovery all satisfied the design requirements.