Research On Monitoring Method Of Cementing Overflow

With the rapid development of economy, the demand and dependence on oil and natural gas have a sharp increase in domestic and external, petroleum countries have accelerated the exploration speed of oil and gas, the steps move toward complex formation. In these formation, it is easy to occur overflow under high pressure, at the same time, high pressure caused by well cementation will lead to underground leakage. All of these cases are likely to cause failed and brought high hidden dangers. So in order to ensure the safety of cementation, we need to monitoring the real-time cementing process and analysis.Grasp the downhole dynamic parameters and judge the downhole Complicated situations, in order to timely adjust the construction plan, make sure that cementing construction work is completed.Based on the characteristics of the cementing overflow monitoring, this paper presents a new cementing overflow detection method and successfully solved the problem that the return volume of cementing slurry can’t be measured. In this method, two standard tanksare used for measuring and monitoring export volume alternately, overflow or not can be judged by comparing the actual monitoring export returns to that of simulation calculation. First, all fluids including mixing slop were calculated exactly. Then, preferably excellent performance sensors to collect wellhead pressure, fluid injection rate, fluid density and liquid level in the tank at any time. Last, electronic signal was send out by wireless transmission box, computer received the data collected by master node. This paper used Bingham, Power-law and Heba pattern to describe rheological model of fluid in borehole. After selecting the suitable rheological model, flow pattern was determined by Reynolds, then the model of calculating circulating pressure loss was set up. In order to understand the downhole complicated conditions, we need to pay attention to underground dynamic parameters, this paper proposed new methods to calculate the position of fluid, pressure in annulus and casing and pressure of concerns. The computational model of dynamic parameters was established combine with Euler model considering U-tube effect. It can based on the construction design and well bore structure data, check the rationality of the design of construction, It also can based on the monitoring of real-time injection rate, fluid density and wellhead pressure, the back displacement, vacuum section height, pressure of concerns and annulus pressure were calculating, Judgment of downhole complicated conditions and early warning and auxiliary construction decisionsFinally, according to the calculation model of downhole dynamic parameter and the monitoring methods, this paper used Visual Studio2010development platform, C#and SQL database to developed an overflow monitoring software, then tests in laboratory and field were carried out and achieved good results which have an important role in cementing security.