Formation Damage Prevention in HPHT Wells: Evaluation of Cellulose Fibre and Granular LCM Using Ceramic Disc Testing

Abstract This paper explores the utilization of a novel plant-derived micronised organic cellulose fibres as a lost circulation control material in High Pressure and High Temperature (HPHT) environments. Lab test is conducted to evaluate, assess, and compare its method of sealing losses, material's temperature resiliency towards degradation and its relation towards the formation damage within HPHT conditions. The organically derived cellulose fibres are compared in its sealing, bridging, structural performance, and thermal resilience to conventional granular LCMs. Laboratory tests such as permeability plugging tests are conducted to evaluate the material's performance as a lost circulation control material (LCM). Resilience of the LCM formulated mud towards high pressure high temperature induced rheological degradation is also assessed to confirm operability within harsh HPHT conditions. To observe the performance of said material, 3 drilling fluids were formulated with the fibres, with granular LCM and without LCM. The fluids were then tested using a Permeability Plugging Test (PPT) apparatus, with a ceramic disc acting as the formation rocks to simulate a generic reservoir with downhole conditions within high pressure conditions. Post-PPT filter cake analysis show that the fibres formed a far more ideal filter cake compared to its counterparts, with minimal invasion found, preventing solid invasion from occurring which leads to formation damage. This is possible due to it creating a lattice like structure which acts as an impermeable barrier preventing solids from intruding. Variation of size based on stephen vicker's criteria for the designated pore throat also increased its effectiveness at sealing loss zones. Hot rolling the material at 300°F for 24 Hours shows no significant degradation induced alteration in properties, this adds an advantage towards the similarly shaped polymer counterparts, which are prone to thermal degradation. The formation damage potential of this LCM is also quantified through the comparison of alterations in disc mass, which highly correlates to reduction in permeability. Organic cellulose fibres application on HPHT downhole, shows efficient performance and minimum formation damage inducing residue as a lost circulation control material (LCM). These fibres create a more impermeable barrier than granular LCMs, halting solid invasion and formation damage. The fibres showed endurance when hotrolled at and 330°F using oil-based fluids, preserving a minimal invasion zone under HPHT circumstances. The fibres also is shown to cause less change in disc mass as a result, hence less potential formation damage. This gives mud engineers a practical way to make mud formulations that are resistant to loss and does not induce formation damage.