阿塞拜疆Bz-1R井超高压固井技术

Bz-1R井是阿塞拜疆Karabagil油田的一口重点探井，其地层压力系数异常，钻井过程中钻井液密度最高达2．28kg／L，且钻井液安全密度窗口窄，易发生溢流或钻井液漏失，固井施工时压稳与防漏的矛盾突出，水泥浆密度的确定、水泥浆浆柱结构设计、平衡注水泥困难。该井井下地层流体活跃，容易在水泥浆候凝过程中侵入环空，影响第二界面的胶结质量而引发环空窜流，压稳防窜候凝困难，加上环空间隙小、水泥浆密度高等的影响，导致该地区固井施工难度极大。为此，研制应用了密度2．3～2．6kg／L性能稳定的超高密度水泥浆体系，采用旁通式自动灌浆浮箍解决了大尺寸套管在高压易漏井的下入问题，配合使用剪销式注水泥前隔离塞及水泥塞定位器，并采取了一系列有针对性的固井技术措施，保证了固井施工的顺利进行，使该井成为该油田第一口固井成功的超高压复杂井。

Ultra High-Pressure Cementing Technology in Well Bz-1R in Azerbaijan

Well Bz-1R with abnormal formation pressure gradient is a key exploration well located in Karabagil Oilfield in Azerbaijan. The drilling fluid density reached up to 2.28 kg/L and the safety range of drilling fluid density is narrow which is easier to cause overflow or lost circulation. The contradiction be- tween the maintaining pressure balance and preventing lost circulation was obvious. It was difficult to determine the density of drilling fluid and the design cement slurry string and to pump cement slurry. The downhole formation fluid was active and prone to invade into the annulus during cement curing which impacted the bonding quality of the second interface and caused channeling in annulus. The challenges in pressure and channeling control along with the narrow annulus and high cement slurry density increased the difficulty in cementing operations in this area. Therefore, the stable cement slurry with ultra-high density of 2. 3-2.6 kg/L was developed. The auto fill-up float collar was employed so that the problem of running large size casing was solved. Combined with the use of pin-type batching plug and cement plug locator as well as a series of other cementing measurements, the cementing operation was ensured so that this well was the first ultra-high-pressure well with successful cementing operation.