Quantitative assessment for the formation fractures in source rock strata and its application

Abstract

Quantitative evaluation of formation fractures and research on the promotion of fractured rocks on formation transport capacity are of certain importance to the exploration of unconventional oil and gas reservoirs. By comparing the rock fracturing pressure under the same confining pressure condition with the confining pressure range of the source rock series, the rock fracturing situation of the source rock series under the action of static rock pressure in the Bonan-Sikou area of Jiyang Depression, Bohai Bay Basin was analyzed. The effect of source rock fractures to the transporting capacity was quantitatively measured. On this basis, a method of comprehensive comparison of confining pressure, fracture pressure and post-fracture conductivity was proposed to study formation fracture. In the upper and middle sections of the third member of Paleogene Shahejie Formation in Bonan-Sikou area, the sandstones and shale rocks in the deeper strata are generally ruptured, and the sandstone layers in the middle strata are regionally ruptured. In the lower section of the third member of Shahejie Formation, the middle and deep strata are generally ruptured. In the uppersection of the third member of Shahejie Formation, the middle and deep strata are generally ruptured, whilst only part of sandstone layer in the upper part is ruptured. The fractured formation has greatly increased permeability and can be used as an effective conduction channel. The methods described above provide a powerful complement to existing "sweet spot" evaluations.

Keywords

• source rock series
• fracture
• transport
• bonan-sikou area
• bohai bay basin