Wider Windows - Drilling Operations/Formation Damage

Objectives

The Wider Windows Industrial Affiliate Program seeks basic understanding of the physics involved in ROP optimizations, well control, wellbore stability, formation damage, and lost circulation in the wellbore and near-wellbore regions while using overbalanced, underbalanced, or casing drilling techniques. These topics are central to well construction activities and costs everywhere. Managed Pressure Drilling (MPD), Dynamic Density Control (DDC), and real-time, automated drilling interests are expanding, both for efficiency and HSE reasons. Workable solutions to a host of practical, operational problems require better understanding of the fundamental, local, and interacting time-dependent processes at work during the complex sequences of events that constitute well construction. 

Research Projects

Changes in permeability due to changes in the state of stress in the reservoir during depletion arise because of the strain that results from the stress changes. This influences permeability around the producing well, as well as permeability throughout the depleted reservoir that affects future wells. Various models exist for coupling stress, strain, and permeability. The simplest models relate changes in stress relative to some reference value to changes in permeability. More complex models invoke the Kozeny equation in accounting for changes in porosity, tortuosity, and surface area.

During the initial pressure buildup of a leak off test (LOT), the increase in wellbore pressure causes porous flow of drilling fluid into the formation as well as deformation of the formation due to the pressure gradient. When the borehole pressure reaches the fracture initiation pressure, the formation yields and fractures initiate and propagate, allowing drilling fluid to leak off more rapidly into the formation.

 

Wider Windows Topical Areas

 

Stress diagram