MEG钻井液在吐哈油田小井眼侧钻井中的应用

吐哈油田小井眼开窗侧钻井主要采用混原油钻井液,不利于环境保护。从研究MEG单体的作用机理入手,以钻井液润滑性、抑制防塌性为主要评价指标,对MEG钻井液配方进行了优选,并对优选配方钻井液性能进行了评价。该钻井液在4口小井眼开窗侧钻井进行了试验应用。结果表明:应用井无阻、卡现象,平均钻井周期缩短了7.2d;在未混原油的情况下钻井液润滑系数比乳化原油(15%~20%)钻井液降低了34.6%;油层保护效果好,其中温5-41C井日产油14.4t,同比温五区块平均产量提高了128.4%,神218C井是神229区块目前唯一的自喷井。表明优选出的MEG钻井液具有优良的润滑性、抑制防塌性及良好的储层保护效果,特别适合强水敏地层及大斜度井和水平井等特殊复杂工艺井的钻进。

Application of MEG drilling fluid in slim hole sidetracking wells

The commingled crude drilling fluid was deployed for slim hole sidetracking and it was not environmentally benign. The reaction mechanism of MEG monomer 'was discussed. The formulation was optimized by taking the lubrication and inhibition of MEG drilling fluid as key evaluation criteria and the optimum formulation was then tested. Four sidetracking wells'practices indicated that no logy or sticking occurred and 7. 2 day rig days saved. The lubricating coefficient reduced by 34. 6% comparing with that of e-mulsified crude oil(15 % - 20 %) drilling fluid. MEG drilling fluid had better formation damage control. WEN 5-41C had a 14. 4 t BOPD and this was greater than that of WEN 5 BLOCK by 128. 4%. SHEN-128C well is a unique gusher well in the SHEN 229 BLOCK presently. It was proved from the data that MEG drilling fluid present excellent lubrication and inhibition and better formation damage control capacity. It is an attractive alternative when drilled in challenge wells including serious water sensitive formation, high angle deviated holes and horizontal wells.