Drilling Research Institute of China National Petroleum Company

Xiaoqiang Zhai

Wei Liu

Kai Wang

Lin Shi

Yingcao Zhou

Boqi Zhou

Ying Wang

Qingfeng Guo

The invention discloses a series of methods to design drilling trajectory and control drilling operations in a optimized way in carbonate formation. The trajectory design method comprises: utilizing earthquake data to obtain contours of the carbonate rock fractures; determining a safe distance from each carbonate rock fracture; determining a segmented drilling trajectory for each fracture or vuggy structures in carbonate formation; and sequentially connecting the segmented drilling trajectories of neighboring fracture and vuggy to obtain a smooth horizontal drilling trajectory. The invention optimizes the carbonate rock reservoir drilling trajectory, thus improving connection between a horizontal well and the fractures. This reduces development costs, increases exploration and development efficiency and, at the same time, eliminates leaks resulting from the drilling process, thereby allowing for smooth drilling to a target well depth.

Methods of well trajectory and drilling optimized control for fracture-vuggy carbonate formation

This invention discloses a method for wellbore pressure correction. The method comprises: measuring a bottom hole pressure using a downhole pressure measurement-while-drilling tool; calculating a predicted bottom hole pressure; and correcting a wellbore pressure using the measured bottom hole pressure and the predicted bottom hole pressure, to achieve managed pressure drilling (MPD). The invention makes up for the defect in the existing art that the difference between a wellbore pressure calculation processing method and the actual downhole pressure is relatively great, and is capable of more quickly and accurately calculating the wellbore pressure in real time so that accurate calculation and real-time correction and control of dynamic wellbore pressure on a narrow density window formation are achieved, thereby meeting the requirement of good bottom hole pressure and the requirement of ensuring safe and quick drilling.

Wellbore pressure correction method

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Beijing, China

Xiaoqiang Zhai