套管井砾石充填工艺优化及盲管外砂高计算方法研究

Process Optimization of Gravel Packing in Cased Hole and Calculating Method of Covered Sand Height outside of Blank Pipe

套管砾石充填工艺普遍应用于渤海油田疏松砂岩油藏的开发,但砾石充填由于工艺复杂和配套工具多等原因,会导致施工事故风险增加,其中砂卡一直是困扰现场施工作业的难题。从砂卡机理进行分析,研究了砾石充填的工艺步骤和盲管外砾石高度的计算模型,通过对砾石充填工艺过程中压力、排量等影响盲管外砾石高度因素进行分析,可知地面泵压的突然升高预示着盲管外堆砂的开始,随泵压增高砾石充填高度不断增大,达到脱砂压力后停注,从而得出套管井砾石充填防砂工艺盲管外砾石高度计算新方法。研究认为:选择适当的参数和计算方法可以计算盲管外砾石高度,不用再次下放服务管柱重新打开滑套,也不用再次开泵循环计算砾石高度,减少了验充填和验滑套的作业步骤,大幅降低了砂卡风险,同时缩短了作业周期,降低了作业费用,且新计算方法计算出的盲管外砾石高度与传统方法计算出来的结果吻合度较高。该研究对套管砾石充填的防砂井具有重大意义。

The casing gravel pack technology has been widely used in the development of unconsolidated sand- stone reservoirs in Bohai oilfield,but the operation risk will increase due to the complex process and down- hole tools.Gravel packing tool stuck in the sand control string is a critical and difficult problem during field operation.Process of the gravel packing and calculation model of covered sand height outside of blank pipe were researched based on the mechanism of sanding in.Pressure,discharge capacity and other factors during the process of the gravel packing will influence the covered sand height outside of the blank pipe.The analy- sis of influencing factors indicates that sudden rise of the ground pump pressure means the beginning of gravel pack outside of the blank pipe.The packed gravel height increases with the rise of pump pressure.The gravel packing will be ended when the pump pressure reach the sand-out pressure.And then a new calcula- tion method of the covered sand height outside of the blank pipe in casing gravel packing wells was formed. The height can be calculated using suitable parameters and calculation method and it is not necessary to low down service tool again to open the sliding sleeve or to open pump circulation again.Thus the test of pack- ing and sliding sleeve will be cut and the risk of sanding in will be reduced.At the same time,the opera- tion time and cost will be reduced.The calculated height by new method is almost the same with that by traditional method.This research is of great significance to the sand control wells in casing gravel packing process.