Oil-based Mud Plays Significant Role in Shale Gas Exploration

Oct 17, 2012

READ: Many unsolved problems in shale gas exploration are mostly attributed to drilling fluids. However, shale’s proneness to hydration swelling, which leads to a string of complex downhole problems like a collapsing wall, has determined oil-based mud to be applied in shale gas exploration.

Many unsolved problems in shale gas exploration are mostly attributed to drilling fluids, so proper match between mud properties and engineering parameters gives birth to safe well drilling. Shale gas is produced by fracking since it mainly exists among cracks. However, shale’s proneness to hydration swelling, which leads to a string of complex downhole problems like a collapsing wall, has determined oil-based mud to be applied in shale gas exploration.

Foreign companies apply a special drilling fluids called oil-based mud, especially in horizontal wells. And they have gained mature technologies and experience from years’ practical application of it.

Foreign oil-based mud’s application in China are still restrained due to high cost, high tariff and high service charge. However, nationwide alternative-energy development for oil-based mud are currently underway. Though it still remains a controversy whether domestic oil-based mud for horizontal drilling project has entered mature stage, it is comparatively stable and costs less.

Today, domestic shale gas exploration mainly takes into account liquid invasion and downhole safety and oil-based mud is designed to protect gas reservoirs so as to reject hydration swelling in mud shale.

Oil-based mud is more protective in terms of safety, good rejection capability, faster drilling speed, etc. Water-based mud can also be adopted on various drilling designs because of its important head start of being cheap. Therefore, application of oil-based mud in shale gas exploration is key to examine how well domestic technologies are united with efficiency.