低成本防水侵水泥浆体系在陇东页岩油水平井的应用

陇东页岩油水平井上部洛河组地层承压能力低,地层水活跃,存在固井难题,现有轻珠体系存在耐压性能差、受压后流变性能恶化且不抗水侵的问题。为此,研发出低成本防水侵耐压低摩阻水泥浆体系,与同密度玻璃微珠体系相比,该体系1 m3浆成本下降50%左右,水下水泥损失量低于0.5%,水陆强度比高于0.85,耐压密度差不高于0.03 g/cm^(3);水泥浆受压后n>0.5,k<1.5 Pa•sn,45℃常压养护48 h水泥石抗压强度大于7 MPa,在水泥浆成本与轻珠体系相差不多情况下,水泥浆性能得到大幅度提升。在陇东的60口页岩油水平井应用,现场施工压力明显降低,未发生漏失,水泥浆返高满足设计要求,洛河水层封固合格率100%,为低压易漏水层固井提供了有力的技术支撑。

煤田巷道防水侵水泥浆材的封堵试验

井下巷道掘进仍然是地下煤炭开采的主要方式,在开采过程中必然要穿过一些断裂地层带以及无胶结的松软地层及煤层顶板上的含水层。在掘进过程中,如果处理不当,地层中的水将沿着裂缝和采空塌陷区大量进入巷道内,造成严重的透水事故,使掘进工作无法顺利进行,严重时将导致井巷的报废,甚至造成重大的人身伤亡事故。针对传统水泥浆经水侵后不凝固或被流动水稀释而完全漏失,起不到应有的封堵固化作用等问题,研制出一种防水侵水泥浆封堵材料。该水泥浆与水按1∶1的比例掺混后仍具有凝结时间快、凝结强度高等特点,可在25℃以上的温度条件下使用。在某煤矿840 m井深、120 m3/h出水量情况下进行堵水作业试验,堵水效果良好,可在类似的条件下推广应用。

Identification of a Lectin Gene Induced in Rice in Response to Magnaporthe grisea Infection

By mRNA differential display, eight induced cDNAs were obtained from rice leaves infected with an incompatible race 131 of Magnaporthe grisea, and one of these cDNAs was highly similar to salt-induced mannose-binding lectin gene. Using this fragment as a probe, a full length cDNA was isolated from a nice cDNA library, which was constructed using mRNA from the incompatible race-infected leaves. Sequence analysis indicates that the cDNA encodes a protein of 15 kD with 145 amino, acids and shares 96% identity at nucleotide level with MRL and salT, but is identical to MRL at amino acid level. Genomic Southern blotting shows that there are two mannose-binding lectin genes in rice genome. Northern blotting analysis indicates that the gene was strongly and specifically induced in rice leaves infected with the incompatible race, suggesting that the lectin induction be involved in the defense of rice to M. grisea.