粉煤灰低密度水泥浆在塔河油田堵漏中的应用

Utilization of fly ash low density cement slurry for plugging in Tahe oilfield

关键词:  二叠系  堵漏  固井  粉煤灰  低密度

Key words:  Permian  plugging  cementing  fly ash  low density

摘要:

作为西北油田的重要勘探开发区块之一,塔河油田托普台区块大部分井存在二叠系,井深4 500～5 200 m,厚度50～300 m,在钻遇二叠系时漏失严重, 塔河10区及12区部分无二叠系井也漏失严重,增加了正常钻进难度,耽误钻井时效,可能诱发井下复杂事故,对油井后期固井等作业影响很大。设计优选粉煤灰低密度水泥浆体系对二叠系进行堵漏。该水泥浆体系密度1.60 g/cm³左右,抗压强度6～8 MPa,漏失严重时可在水泥浆中添加5 mm、10 mm纤维进行复合堵漏,纤维在裂缝中架桥,形成空间网状结构,提高堵漏效果。该水泥浆体系在现场多口井的堵漏作业表明,能有效地提高地层承压能力,大大缩短了钻井周期,为后期钻井及固井施工创造了有利条件。 

Abstract:

As one of the important exploration and development blocks in the northwest oil field, most of the wells exist Permian in the Tuoputai block at Tahe oilfield, with depth of about 4 500-5 200 m and thickness of 50-300 m. The loss is severe when drilling during the Permian, at the same time, parts of the non-Permian wells are also leaking severely in Tahe 10 and 12 blocks, which increase the difficulties in normal drilling, delay drilling time, it will lead to complex underground accidents, and has great influence of well cementing etc.in the late homework. The fly ash low density cement slurry system was prioritized to plug the Permian in this paper. The density of the slurry system is 1.60 g/cm³, the strength of compression is 6-8 MPa. It could add 5 mm and 10 mm fiber in the cement slurry when the leakage is severe. The fiber is bridged in the crack to form the structure of net space, and improved the plugging effect as well. Through plugging operations of several wells in the field, it could effectively improve the bearing capacity of the formation, greatly saved the drilling cycle and created favorable conditions for the later drilling and cementing construction.