哈萨克斯坦肯基亚克油田盐下水平井钻井液技术

肯基亚克盐下油田地质构造复杂,地层倾角大,储层埋藏深,巨厚盐膏层易蠕变缩径和污染钻井液,下二叠系储层中存在异常高压气层(1.98~2.05)和裂缝性漏失层,钻井液密度窗口窄,漏喷转换致使井控风险大。多年开采,地层压力衰减造成区域内地层压力系数难以确定,高低压同层导致钻井周期长,复杂事故多,溢漏矛盾突出,井控风险高等技术难题。现场通过持续优化钻井液体系配方、堵漏材料及堵漏浆配方,细化润滑防卡处理措施,现场应用结果表明,复合盐水钻井液体系抗盐钙污染能力强,润滑防卡效果好,防漏堵漏效果显著,较好地解决了该区块定向水平段高低压同层造成的卡钻和漏喷转换等技术难题,为该区块后续水平井施工提供了技术支撑和借鉴经验。

Drilling fluid technology of horizontal well under salt in Kenjiyak oilfield,Kazakhstan

Kenjiyake oilfield is characterized by complex geological structure,large dip angle,deep buried reservoir,creep shrinkage and pollution of drilling fluid,There are abnormal high pressure gas reservoir(1.98-2.05)and fractured leakage layer in the lower Permian reservoir,and the drilling fluid density window is narrow,The risk of well control is high because of the lost circulation.For many years of mining,the formation pressure attenuation makes it difficult to determine the formation pressure coefficient in the area,and the same layer of high and low pressure leads to a long drilling cycle,many complex accidents,and prominent leakage contradictions,The risk of well control is high because of the lost circulation.For many years of mining,the formation pressure attenuation makes it difficult to determine the formation pressure coefficient in the area,and the same layer of high and low pressure leads to a long drilling cycle,many complex accidents,and prominent leakage contradictions,The results of field application show that the composite salt water drilling fluid system has a strong ability to resist salt and calcium pollution,The effect of lubrication and blocking is good,and the effect of leakage prevention and plugging is significant,It solves the technical problems such as stuck in the same layer of high and low pressure in the directional horizontal section of this block,and provides technical support and reference experience for the subsequent horizontal well construction in this block.