Research and application of coring technology for fire flooding formation in D66 block, Liaohe Oilfield

This paper carries out the research of the drilling coring technology for the fire flooding formation, in order to improve the core harvest rate of fire development formation. On this basis, the coring tools had pointed improvement, drilling parameter had been optimized, and the coring practice of three wells had been completed. The research shows that the fire flooding plays an important role in reservoir reconstruction. It is mainly manifested in 3 aspects as follows: First, the fire flooding causes the formation temperature to increase greatly. Second, baking at high temperature causes rapid dehydration of smectite and rapid expansion smectite when exposed to water. As a result, cementitious materials break apart and loose cementation, resulting in loose formation. Third, the high temperature and strong alkali environment formed by fire drive can dissolve the rock skeleton grain quartz, leading to the loose formation or even collapse. For the high-temperature unconsolidated formation after fire flooding, the core harvesting rate can reach 77.96 to 88.32 persent, which is higher than the conventional coring rate from 44 to 54.36 percentage points, by comprehensively applying such coring tools as high-temperature sealing fluid, anti-erosion bit, composite core talons, aluminum alloy inner tube and PVC lined pipe, combined with the drilling parameter design of " high drilling pressure, low drilling rate and small displacement” . This paper aims to summarize the successful experience of coring in strata after fire flooding of D66 block and provide reference for coring job in other areas.