韦5径向井钻井液工艺技术

韦5径向井是利用原韦5井直接在8号油层部位钻径向水平井眼，目的是增大油层的泄油面积，开采韦5块剩余油。设计了暂堵型保护油气层有机正电胶段铣钻井液体系，该体系利用黑色正电胶BPS的高正电性，将钻井液中膨润土连接成网，从而配制出动切力在10Pa以上的段铣钻井液，满足了铁屑的携带和悬浮；设计了甲酸盐无固相射流钻井液体系，该体系不含污染油层的固相颗粒，配浆水取自原来韦5井地层水，避免了液相对油层的损害；设计了钻井液的密度、切力、硬度、pH值，讨论了钻井液的现场配制、维护措施；韦5径向井钻井液满足了工程需要，保护了储层。

DRILLING FLUID TECHNOLOGY IN W5 RADIAL HORIZONTAL WELL

W5 radial horizontal well was finished in the oil zone of former W5 well, its purpose is increasing drainage area, and recovery remaining oil in W5 block. The bridging type protecting reservoir milling drilling fluid system was designed in the well. The principle of the system is that electropositive BPS join the electronegative clay to a net, make-up the milling drilling fluid with high shearing force of 10 Pa to meet the requirement of entrainment and suspension of iron scale. At the meanwhile, the formate clay-free drilling fluid system is designed, it is no solid grain of contaminated reservoir, and the mixing water is from the W5 formation water, so it avoids damage to reservoir. Drilling fluid density, shearing force, hardness, PH is also programmed. The paper discussed the field preparation of drilling fluid suited for W5 radial horizontal well and maintenance measures. The drilling fluid in W5 radial horizontal well met the need of drilling engineering, and protected the reservoir.