关键词: 复杂地质建模, 三维井轨迹设计, 地震导向钻井, 钻井实时校正, 预测深度

Abstract: At present, strong structural deformation aggravates the difficulty of well trajectory design and construction, making the predicted depth far from the actual depth. In addition, the existing seismic steering drilling technology is not yet mature. To solve the above problems, in order to efficiently and accurately complete pre drilling geological evaluation, well trajectory design and real-time drilling correction, this paper proposes a seismic steering drilling method and process based on 3D geological modeling, which is divided into three stages. First, complex geological modeling. After setting initial parameters of the model, section modeling and layer modeling, a fine 3D structural model is obtained, and on this basis, a reservoir sensitive attribute model is generated. Second, 3D well trajectory design. According to the characteristics of structure, reservoir and oil and gas reservoir reflected by the attribute model, and in combination with the needs of drilling engineering, the well trajectory is designed and picked up in the 3D attribute model. Third, create the “marker bed inverted triangle layer by layer approach method” to conduct velocity depth interactive correction, correct the velocity volume through the newly drilled marker bed depth, so that the depth domain 3D model gradually approaches the real underground model, and the predicted depth of the target entry point constantly approaches the real depth, timely guide the drilling direction and avoid drilling risks. The technical process has achieved good results in practical application, the error rate of prediction depth is less than 0.2%, and the work efficiency is improved by 5 times.

Key words: complex geological modeling, 3D well trajectory designing, seismic guided drilling, real-time drilling correction, predicted depth