胜利青东区块沙河街组井壁稳定钻井液技术

青东区块位于济阳坳陷青东凹陷北部断阶带.沙河街组的地质构造复杂,局部断层发育,断层以下地应力作用明显,沙三段泥岩硬而脆,层理性强,从而使钻探中井壁失稳严重,曾经多次发生复杂事故,轻者反复划眼,严重者则卡钻,严重地制约该区块的勘探开发进程.通过优选铝胺抑制、封堵、防塌钻井液体系,并且在施工中采用合理的钻井液液柱压力支撑和联合多元协同抑制-强封堵-合理地控制流变性等技术措施,配合相应的现场维护处理工艺,保证了青东古1井沙河街组的井壁稳定,使该井提前完钻,钻井周期缩短了20％.

Drilling Fluid Techniques for Borehole Stability in Shahejie Formation of Qingdong Block in Shengli Oilfield

Qingdong Block is located in northern faulted zone, Qingdong sag in Jiyang Depression. The geologic structures are complex in Shahejie Formation, faults are well developed locally, and ground stress is clear below the faults. The mudstones in Sha-3 Member are hard and crisp, and lamination is clear. The borehole was very instable during well drilling, and complex accidents occurred frequently. Repeating dummy trips occurred frequently, and stick was severe case, which slow down the exploration progress in the study area severely. By using aluminum-amino inhibitive, sealing and anti-caving drilling fluid, many measures were taken, such as suitable density supporting, multi-variate synergism inhibition, compelling formation sealing, and reasonable rheological behavior controlling. In addition, corresponding onsite maintenance technology was taken, which guaranteed the borehole stability of Well Qingdonggu-1 in Shahejie Formation. Well Qingdonggu-1 was completed in advance, and borehole was stable in Shahejie formation. In addition, the drilling period was shorten by 20%.