Comprehensive Multiple Fracture Pressure Analysis Tests to Appraise and Develop Unconventional Organic-Rich Carbonaceous Shales in North Kuwait

Fidan, Erkan (Kuwait Oil ) | Darous, Christophe (Schlumberger) | Bloushi, Taha (Kuwait Oil) | Pradhan, San P. (Kuwait Oil) | Singh, J.R. (Kuwait Oil ) | Dashti, Qasem M. (Kuwait Oil ) | Al-Mutairi, Mubarak D. (Kuwait Oil )

OnePetro 

Abstract 

A comprehensive diagnostic data-fracturing campaign (Fracture Pressure Analysis: FPA) was undertaken by the Gas Fields Development Group (GFDG) of North Kuwait in January-March 2013. The campaign involved executing FPAs on the primary zone of interest (Organic-rich Carbonaceous Shale: OCS) as well as underlying and overlying carbonates to establish “fraccability” and in particular the hydraulic frac vertical containment aspect, which are much needed for the successful planning of an appraisal program. 

This paper summarizes the resuts of those FPA tests and how the acquired data is used to calibrate the wellbore geomechanical model. This initial FPA campaign is the onset of a more comprehensive evaluation program planned for 2013 onwards. FPA sequences were executed on the OCS, underlying and overlying formations with encouraging results. The main concern was whether the OCS would yield hydraulic fracture (fracture initiation) below surface treatment pressure limitation of 13,500 psi (Maximum allowable surface pressure). The fracture initiation was successfully established in all three zones. In addition, multiple “fracture re-opening tests” were performed to evaluate the ranges of the fracture closure stresses during the leak-off. Multiple down-hole memory gauges were utilized to ensure elimination of wellbore effects on treatment pressure. KCl-laden incompressible water-based fluid system enhanced with friction reducer was utilized in all three stages to ensure minimal friction loss and damage. This formation suite has very complex mineralogical attributes as it is a mixture of clastics, carbonates and hydrocarbons, with reservoirs that can be very tight (possibly at micro-Darcy). 

This campaign will lead to an optimal selection among the vertical completion options (hydro-fracturing design), and will help to successfully plan for horizontal well completions.