Study On Environmental Friendly Drilling Fluid For Leak Resistance And Sealing

Loss circulation is one of the most complex situations which can harm the safety of drilling operation. It causes not only time and economic loss to drilling engineering, but also brings difficulty to oil and gas exploration. So loss circulation has been a very important problem in the field of petroleum engineering. Recent years, loss circulation problem that happened in deep formation of ancient buried hill in Bohai Oilfield is serious.In view of the formation characteristics of ancient buried hill in Bohai Oilfield, firstly, some common drilling fluid sealing agents were evaluated. Environmental friendly leak resistance and sealing drilling fluids were developed for leaking formation and fracture formation respectively. The evaluation experiments show that the two newly leak resistance and sealing drilling fluids have good stability, high anti-pollution ability and are biodegradable easily, and can satisfy the standard drilling engineering in offshore oilfield. The sealing effect experiments demonstrate that the two newly leak resistance and sealing drilling fluids can enhance the pressure bearing ability of formation and have obvious leaking resistance effect. Core flowing experiment shows that the two newly leak resistance and sealing drilling fluids can protect reservoir.