页岩气开发水基钻屑的生物急性毒性测试研究

Study on acute biological toxicity test of water-based drill cuttings in shale gas development

为探究页岩气开发过程中水基钻屑的生物急性毒性等级,以川南页岩气开发区域某井区开发平台钻井过程中产生的水基钻屑为研究对象,以明亮发光杆菌T_(3)(Photobacterium phosphoreum T_(3))为受试物种,通过试验评价其生物急性毒性等级。试验过程中主要考察水基钻屑生物急性毒性测试液的制备条件对其生物急性毒性测试的影响,结果表明:在浸提剂与水基钻屑的液固比为5 L/kg,浸提剂pH为5,振荡18±2 h后静置30 min的条件下得到的中层液为水基钻屑生物毒性测试液;当水基钻屑测试液pH为8时,将其稀释50倍后对明亮发光杆菌T_(3)的发光抑制率为52%以上。根据不同受试物种对水基钻屑生物急性毒性测试方法适应性分析可知,以斑马鱼(Brachydaniorerio)为受试物种的水生生物急性毒性测试方法(GB/T 13267—91)与以明亮发光杆菌T_(3)为受试物种的生物急性毒性测试方法(Q/SY111—2007)对水基钻屑的生物急性毒性重复测试结果较为稳定,与标准物质测试结果对比P<5%,证明水基钻屑测试液能客观反应水基钻屑的生物急性毒性等级。该研究不仅能为前端环境友好型钻井工作液开发提供参考,也能为后续水基钻屑的处理处置、特别是为后续采用发光细菌法为油气田勘探开发产生的固废、不溶性固体材料等的生物毒性分级及检测提供一定参考。

In order to explore the acute biological toxicity level of water-based drill cuttings during shale gas development,the water-based drill cuttings generated during drilling in the development platform of a well area in a shale gas development area in South Sichuan is used as the research object.The acute biological toxicity level is evaluated by the test using Photobacterium phosphorium T_(3) as the test species.During the test,the influence of the preparation conditions of the water-based drill cuttings biological acute toxicity test fluid on the acute biological toxicity test is mainly investigated.The results show that the liquid-solid ratio of leaching agent and water-based drill cuttings is 5 L/kg,the pH of the leaching agent is 5,and the middle layer liquid obtained under the conditions of shaking for 18±2 h and then standing for 30 min is the water-based drill cuttings biotoxicity testing liquid.The luminescence inhibition rate of water-based drill cuttings testing liquid diluted 50 times at pH 8 to Photobacterium phosphoreum T_(3) exceeds 52%.According to the adaptability analysis of different tested species to the acute biological toxicity test method of water-based drill cuttings,the test method for acute toxicity of aquatic organisms with zebrafish(Brachydaniorerio)as test species(GB/T 13267—91)and the acute biological toxicity test method with Photobacterium luminescens T_(3) as the tested species(Q/SY111—2007)are stable to repeated test results for bioacute toxicity to water-based drill cuttings.Compared with the test results of standard materials,P<5%,which proves that the water-based drill cuttings testing liquid can objectively reflect the acute biological toxicity level of water-based drill cuttings.This study can not only provide a reference for the development of working fluid for environmentally friendly drilling at the front end,but also provide a certain reference for the subsequent treatment and disposal of water-based drilling cuttings,especially for the subsequent biological toxicity classification and detection of solid wastes and insoluble solid materials produced by the exploration and development of oil and gas fields using luminescent bacteria method.