双岩心爪取心工具的研究与应用

复杂地层一般是指裂缝发育，软硬互层，胶结性、稳定性及强度较差的地层，在对该地层进行取心施工时，一直存在撸心、掉心、岩心收获率低等问题。依据复杂地层的特点，研制了双岩心爪取心工具，该工具结合了自锁式取心工具与加压式取心工具的优点，在软地层割心时，可以通过加压式岩心爪将岩心割断并封堵内筒，防止撸心、掉心；在硬地层割心时，启动自锁式岩心爪，楔入岩心，将岩心割断。现已在大庆地区进行了两口井的现场应用，应用表明，该工具有良好的地层适应性，工艺操作简单，成本低，能够有效提高复杂地层取心收获率指标，保证化验分析的准确度，为油田的高效开发提供可靠的地质依据。

Development and application of coring tools with double core catchers

Complex formations refer to those with abundant fractures, alternating soft and hard layers, and poor cementation, stability and strength. Coring operations in complex formations often encounter such problems as core ripping, core disengagement and low core recovery. In light of features of complex formations, a coring tool with double core catchers has been developed. With combined advantages of self-locking and pressurized coring tools, the newly-developed coring tool may effectively cut the core and properly secure it in the inner barrel during coring operations in soft formations by using the pressurized catcher, in this way, the captured core can be protected against ripping and disengagement. While in coring operations in hard formations, the self-locking core catcher can be mobilized to penetrate into and cut the core. This tool has been used in two wells in Daqing Oilfield. On-site application shows this tool, with good formation adaptability, simple operation and low costs, can effectively enhance core recovery in complex formations to ensure accuracy of lab analysis, so reliable geologic data can be provided for highly efficient oilfield development.