乍得潜山花岗岩地层欠平衡钻井试验

摘要

Reservoirs have been discovered in the granite formation of the buried hill of Bongor Basin in Block H of Chad by CNPC International (Chad) Ltd. The granite formation of the buried hill of Bongor Basin has low formation pressure (fracture pressue 1.0) and well developed fractures, which can easily result in severe loss during drilling operation. In view of the advantages of UBD technology in improving discovery, increasing ROP, avoiding downhole troubles and protecting reservoirs, it was decided that UBD technology was used to drill the granite formation of the buried hills in Bongor Basin. This paper presents a preliminary UBD program based on the analysis of geological conditions and previous drilling in the granite formation in the buried hill of Bongor Basin, analyzes the trial test of two UBD wells, and makes suggestions for improving ifeld tests.%中石油海外乍得项目在乍得H区块Bongor盆地花岗岩潜山地层发现了油藏。Bongor盆地花岗岩潜山地层压力低（压力系数1.0），裂缝发育，钻进过程中极易发生严重井漏。鉴于欠平衡钻井技术在提高油气发现、钻井速度，避免井下复杂情况和保护油气层等方面的优势，决定采用欠平衡钻井技术钻探Bongor盆地花岗岩潜山。在分析Bongor盆地潜山地质和前期钻井情况的基础上提出了欠平衡钻井初步方案，对前期欠平衡钻井2口井的试验情况进行了分析，对完善现场试验提出了建议。