松科一井长裸眼防塌钻井液技术

松科一井是为研究“白垩纪地球表层系统重大地质事件与温室气候变化”而进行的科学钻探井，该井地层主要为松散的流沙层、松软泥岩、水敏性泥岩和砂岩互层。对钻井液的抑制性、黏结性和降滤失性进行了研究，并对相应处理剂的作用机理进行了分析，得到DFD+LG+Na-CMC钻井液配方体系。为了直观地测试评价所配钻井液护壁能力的强弱，模拟井内情况，设计加工了井壁稳定模拟测试仪，通过实验得出在不同钻井液护壁作用下，井壁发生坍塌的破坏压力，从而测试出各种钻井液的防塌护壁能力。现场应用表明，该钻井液体系具有很好的抑制性和黏结性等防塌护壁性能，井壁在长期裸眼取心作业情况下，仅靠该钻井液进行护壁即可维持长裸眼钻进到完钻，井壁从没发生缩径或坍塌，从而保证了整个工程顺利、安全地进行，同时还避免下套管护壁，节约了工程成本。

Anti-sloughing drilling fluid technology for bare hole in CCSD-SK1

CCSD-SK1 is an exploration well aimed at probing into the grand geological event and greenhouse climate change in the earth surface system during the Cretaceous period. Drifting sands, fluffy mudstone, water sensitive mudstone and sandstone and alternate layer take the majority in the formation of the well. Research is conducted on the strong rejection capability, binding property and filtration reduction of drilling slurry system, the active mechanism of relevant treating chemicals is analyzed. So the mud system of DFD + LG + Na-CMC is found. In order to test and evaluate the protective capability of the driling fluid, a tester to simulate borehole stability is designed and developed by simulating borehole situations. The breaking pressure caused by the collapse of wellbore is derived from the test, so the anti-sloughing capability of different driling fluids is tested. Field application shows that the drilling fluid system has good rejection capability and binding property. In the situation of coring in bare hole, only using the driling fluid may keep drilling in bare hole up to well completion, and wellbore does not shrink or slough. The technology ensures the field work to run successfully, and also avoids casing to decrease cost.