渤海渤中区域深井井身结构优化

深井钻井需要考虑对不同压力层系和复杂地层封隔，井身结构是确保钻井作业优快钻达目的层的重要影响因素。以渤中区块深井为例分析了井身结构优化设计过程，通过渤中区域深层地质分析和随钻测井实时数据，基于多源数据融合技术对钻前压力预测模型不断实时更新，得到较为精确的钻前孔隙压力，再根据地质特点、井控、三压力剖面等因素对井身结构进行优化设计，通过减少技术套管的层数、优化套管下深，将原六开井身结构优化为五开，形成一套适合该区域的井身结构。该技术可以在保证钻井安全的前提下，有效地规避作业中可能出现的复杂事故，以达到缩短钻井周期和提高机械钻速的目的，也可以为后续海上深层钻井作业井身结构设计提供参考。

Casing program optimization of deep wells in the central Bohai area

In the drilling process of deep wells, it is necessary to isolate the formations with different pressure systems and the complex formations. And casing program is an important influential factor to ensure the drilling of target layer fast and optimally. In this paper, the optimized design process of casing program was analyzed by taking the deep well in the central Bohai Block as an example. The predrilling pressure prediction model was updated continuously in real time by means of multi-source data fusion technology, based on geological analysis and real-time data of logging while drilling of the deep layers in the central Bohai area, so that the obtained predrilling pore pressure is more accurate. Then, the casing program was optimally designed according to geological characteristics, well control and three-pressure profile, and the original six-section hole structure was optimized into the five-section by reducing the number of technical casing layers and optimizing the casing setting depth. Thus, a set of casing program suitable for this area was developed. This technology can effectively avoid the complex accidents that may occur in the process of operation under the premise of ensuring the drilling safety, so as to reach the target of shortening the drilling cycle and improving the rate of penetration (ROP). And it can also provide references for the casing program design of offshore deep drilling operation in the following step.