SAGD平行井套管内磁引导模拟实验

Simulation Experiment of Guiding with a Magnetic Source inside the Casing of SAGD Twin Well

摘要:

SAGD平行井是稠油开采的重要方法，它对两井的空间轨迹要求较高。相比较常规随钻仪器，借助于MGT磁定位的磁引导技术有利于进一步提高钻孔轨迹检测精度和检测效率。目前还未见国产同类成熟仪器应用的报道。主要介绍了室外套管地面模拟实验，研究轨迹精度与套管内磁响应之间的关系，为仪器的实际应用提供修正数据和技术支撑。实验以通电螺线管作为磁发射源，并置于φ139.7 mm套管中，以磁传感器为接收源，采集数据，最后由电脑解析数据算出两者的相对位置。实验时不断改变传感器与套管的相对位置，以模拟钻头钻进的真实情况。实验共采集了18种形态，共198点位数据。在修正前，计算的总距离平均误差在7%左右，平面误差为9.4%左右。修正后误差为之前的一半。结果表明，计算点能够真实反映轨迹的实际方向。

Abstract:

SAGD twin well is an important technology for producing heavy crude oil, which demands a lot controlling about the two wells’ trajectory. It’s good to improve the drilling trajectory measuring accuracy and efficiency with the help of MGT technology instead of MWD. At present, there is no report on the application of similar mature instruments made in China. This article mainly introduces an experiment performed on the ground, which tries to find the relationship between the trajectory accuracy and magnetic source inside a casing to provide data and technical support to the practical application. A solenoid which is put into a 139.7mm casing as a magnetic emitter and a magnetic sensor are placed to simulate real drilling situations of SAGD, the relative positions of the twin well are finally worked out by computer analytic data. In the experiment, the relative position between the sensor and the casing is continuously changed to simulate the actual situation of bit drilling. 18 trajectory patterns are collected with 198 point sites data. Before correction, the average errors of calculated total distance was about 7% and the plane errors are about 9.4%; after correction, the errors are reduced to only half the previous ones. The results show that the calculated points can really reflect the actual direction of the trajectory.