钻井液脱气效率现场试验研究

A Field Test Study on Degassing Efficiency of Drilling Fluid

钻井液脱气效率是影响气测录井准确性的一项重要参数,对发现、解释、评价油气层具有重要意义。由于过去多是定性的解释评价,脱气效率的数值很少有人进行现场测量。为了准确获取该参数,并探讨其影响因素和规律,从不同思路、不同原理设计了2种测量脱气效率的试验方案,即全脱值-气测值法和全脱值-全脱值法,选取了5口钻井液性能差别不大的井,采用2种方法分别进行试验,得出了不同烃组分的脱气效率值。对其试验结果进行对比分析表明,对于同一烃组分,不同井别、不同方法所测得的钻井液脱气效率值基本相同;随着烃类气体碳原子数的增加,脱气效率逐渐降低。在录井工程中,可利用该值对气测值进行实时校正,提高录井资料的准确性,为后期的解释评价奠定基础。

Degassing efficiency of drilling fluid is one of the important parameters in gas logging,which has great significance for discovering,interpreting and evaluating oil and gas reservoir.Previous qualitative evaluation allows few operators to make field measurement of this parameter.In order to collect the right parameters and analyze their influence factors and laws,this paper presents two testing programs called ＂VMS（vacuum mud still） value-GL（gas logging） value＂ and ＂VMS value-VMS value＂ in accordance with different ways and theories.After application of these methods respectively in five wellbores which have similar drilling fluids,they produced different degassing efficiencies of different hydrocarbon components.The results,by contrast,indicate that different wells or measuring methods of the same hydrocarbon components have the same degassing efficiency.As the increasing of carbon atoms,the degassing efficiency is reduced.Therefore,the real-time correction can be used in mud logging in order to improve the accuracy of logging data and lay a foundation for further interpretation and evaluation.