大牛地气田长水平段井眼轨迹控制方法

Trajectory control methods for long sections of horizontal wells at the Daniudi Gas Field

准确掌握钻具组合与地层相互作用表现出来的造斜率是控制水平井井眼轨迹的关键。为了实现对鄂尔多斯盆地大牛地气田长水平段水平井井眼轨迹的高效控制,利用大牛地气田长水平段实钻资料进行了统计分析,获得了使用特定钻具组合在复合钻进条件下地层可钻性级值与井眼全角变化率的对应关系。以此为基础,结合螺杆钻具的实际造斜能力,提出了以地层可钻性级值作为设计依据,构建适应地层可钻性的底部钻具组合设计指导原则,并结合现场应用情况形成了考虑岩石性能变化的井眼轨迹控制方法。该方法提高了底部钻具组合及钻进参数优选的针对性和可操作性,进而可达到提高复合钻进进尺比例和长水平段井眼轨迹控制效率的目的。还从井眼轨迹控制技术的角度出发,提出了一种用于钻具组合及钻进参数优选的地层分级方法,并在实际钻井过程中得到了应用和验证。

The key to the horizontal well trajectory is to accurately control the buildup rate affected by the interaction between the bottomhole assembly(BHA) and the rocks.In order to make the horizontal well trajectory control even more effective,a statistic analysis is conducted on the actual drilling data from the long horizontal wells at the Daniudi Gas Field,from which a corresponding relationship is obtained between the formation drillability and the hole dogleg severity when the specific BHA is used to drill a horizontal section under the rotary drilling situation.On this basis,according to the actual building rate of positive displacement motor(PDM),the formation drillability is regarded as the basis for the BHA optimization design,in combination with the field practices,the trajectory control method is thus developed considering the properties of different rocks.This method improves the BHA performance and achieves good results of the drilling parameter optimization,thereby enhances the accumulated drilling footage and the horizontal trajectory control effects.Furthermore,a new formation classification method is also introduced herein to optimize BHA and drilling parameters,which is applied and verified in many drilling practices.