巴什托油气田高密度钻井液技术研究

Application of high density drilling fluid technique in Bashituo oil gas field

常连玉

CHANG Lianyu

中石化石油工程技术研究院，北京　100101

Research Institute of Petroleum Engineering Technology, SINOPEC, Beijing 100101, China

为解决巴什托油气田在钻井过程中存在的盐膏侵严重、井壁失稳、井底温度高、存在高压层、易漏失等一系列难题，通过优选膨润土加量、抗高温处理剂、加重剂等，开发出一套适合巴什托地区的高密度钻井液体系。该体系密度达到2.20 g/cm3，抗温可达160 ℃，具有良好的热稳定性、抑制性能和抗污染能力。在BK8H井进行了现场应用，施工过程中钻井液性能良好，未发生任何井下事故和井下复杂情况，顺利钻穿440 m的盐膏层，三开井径扩大率为2.33%，而且与该区同类型井相比缩短了钻井周期，表明该高密度钻井液体系完全适应巴什托区块复杂条件下的钻井要求。

formation intruded seriously by salt bed, wellbore instability, high temperature in downhole, within high pressure layers and leakage were all made the drilling difficult in Bashituo oil gas field. A set of high density drilling fluid suitable for this area was developed to settle the problem by optimizing the bentonite concentration, High temperature resisting additive agent and weighting agent. The density of this system can reach up to 2.20 gram per centimeter while temperature can get as high as 160 degree. The drilling fluid was used in field experiment in Well BK8H and has gained well results due to thermal stability, inhibitive character and resisting pollution. During the treatment in Well BK8H, the fluid system performed well, no accident and other complex situation happened downhole. Due to this, salt bed with 400 meters was drilled though smoothly, and the enlargement rate of re-drilling well was 2.33percent, besides, the drilling cycle of this well was shorter than that of the similar well in the same area. All these illustrates that the high density drilling fluid system meet the drilling requirement under complex conditions in Bashituo blocks.