典型页岩气油基钻屑的组成分析及危害评价

COMPOSITION ANALYSIS AND RISK ASSESSMENT OF TYPICAL OIL-BASED DRILL CUTTINGS FROM SHALE GAS FIELDS

分别从重庆某两个页岩气井场选取水平井油基钻屑(A)和直井油基钻屑(B)样品,详细分析其基本性质及组成。结果表明:油基钻屑由72.78%~81.34%的灰分、14.14%~26.21%的有机物和1.01%~4.52%的水分组成。灰分来源于钻井液中的无机添加剂和钻头破碎的岩石碎屑,主要成分为CaCO_3、BaSO_4、SiO_2和Fe_2O_3。有机物来源于调制钻井液的基础油和各类有机添加剂,主要成分为烷烃、多环芳烃、苯系物和烯烃。碱性盐、重金属和有机物是油基钻屑中的三类有害物质,且其危害依次增加,若不加以有效处置,将对当地生态环境和人类健康造成持久性破坏。

Two typical oil based drilling cuttings（ OBDC） were taken from a vertical well（ A） and a horizontal well（ B） in Chongqing shale gas fields,respectively. Their basic properties and composition were analyzed in detail. The results indicated that the OBDC consisted of ash of 72. 78% - 81. 34%,organic matter of 14. 14% - 26. 21%,and water of 1. 01% - 4. 52%.Inorganic salts and solid oxides were derived from inorganic additives in drilling fluids and detritus. The main constituents were CaCO3,BaSO4,SiO2 and Fe2O3. Organic compounds came from basic oils and various organic supplements. The main components were alkanes,PAHs,benzenes and olefins. Alkaline salts,heavy metals and organic matter were three kinds of toxic substances in OBDC,and their hazards increased in turn. If not disposed properly,they would cause long-term damage to the local ecological environment and human health.