Farid Shirkavand

The Design and Development of a Drilling Simulator for Planning and Optimizing Under-Balanced Drilling Operations

Computer simulation technology has been widely applied in many drilling engineering areas to simulate drilling engineering problems and optimization, to train engineers with real drilling operations and/or to handle rare applications and accidents. Among the increasingly applied drilling operations is underbalanced drilling (UBD). UBD is the drilling process in which the wellbore pressure is intentionally designed to be lower than the pressure of the formation being drilled. This results in a higher rate of penetration (ROP) and prevents fluid losses and related causes of formation damage. This paper presents the design and development of a UBD simulator, which is computer software that simulates and integrates the effects of: • Bottomhole pressure (BHP). • Minimum volumetric gas and liquid requirement. • Required backpressure (BP) for required cutting removal to surface and controlling BHP. • Kinematic energy per unit volume used in the hole cleaning considerations. • Stand pipe pressure (SPP). • Rock drillability. • ROP. • Drilling costs per metre. The goal of the simulator is to enable the user to pre-simulate different scenarios of the UBD drilling operations; therefore, the ideal optimized combination of drill bit durability and drilling efficiency, integrating all UBD operational parameters affecting the overall cost, can be obtained before the fact. The UBD simulator is designed to simulate most of the basic technologies of UBD (air, aerated and foam drilling). The goal of the UBD simulator is to design an effective UBD program by linking the BHP to rock drillability, which takes into account the effect and degree of under-balance on the effective rock strength, ROP and

Advanced Drilling Simulation Proves Managed-Pressure Drilling (MPD) Economical in Gasfield Developments in Western Canada

/m that can be optimized for the operation. The complete UBD optimization integration is shown herein with illustrations including flowcharts.

Well Construction Optimization in the Montney Formation in the Karr Kakwa Area of Central Western Alberta: A Case Study

The application of managed pressure drilling (MPD) is becoming more widely spread throughout the world. It is well known that MPD has less hydrostatic head during drilling therefore the rate of penetration (ROP) is increased. This is due to the reduced rock confinement and chip hold down effects. By simulating the conventional drilling and MPD of a well in advance the benefits of MPD can be quantified in terms of increase in ROP and therefore the economical benefits. Applying a commercially available drilling simulator (1) . meter by meter drilling performance is analyzed, first simulating and optimizing a conventional drilling operation and then performing the same procedure for a MPD operation in Western Canada. The additional costs of the MPD operation are integrated into the economical analysis. The analysis shows that the ROP during MPD in the higher mud weight regime of the well is improved from 60 to 80 percent. In addition to the faster drilling during MPD the drill bits last longer due to the lesser hardness of the rock being less confined and therefore also reducing the amount of bit wear and the number of bits required and tripping time. Overall the results indicate that the MPD operation reduce the drilling cost of gas wells in Central Alberta more then 20 percent and due to the reduced time at the location less environmental impact is seen.