Definition - What does Fissure mean?
A Fissure is a deep crevice or separation in a geological formation. It is a crack formed as a result of stress exceeding the strength of a rock, which divides the rock into pieces. This provides access to fluids such as hydrocarbons or even water to flow into the rock. When a rock is Fissured, it can be transformed into a good hydrocarbon reservoir due to its permeability and porosity. At times the cracks are induced mechanically by the use of drilling and hydraulic fracturing techniques in a wellbore; this is done so as to improve its permeability.
Petropedia explains Fissure
A crack within a rock usually occurs when the rock is not strong enough to hold too much stress or pressure; thus, the rock cracks along its weakest points. A Fissure can improve the permeability of a rock as it helps in connecting the pores together. Due to this reason, sometimes cracks are induced mechanically so as to boost the flow of hydrocarbons. To generate cracks, special engineered drilling fluids are pumped at a high pressure into the reservoir. A Fissure can enhance the production of a reservoir with improved permeability; however, in other cases the reservoir stimulation may be complicated.