Abstract Between 2010 to 2013, three onshore appraisals well are drilled in the southern part of KG Basin, aiming to appraise economical potential of oil reserved from Late Jurassic Cretaceous petroleum system. Some of the major inherent challenges of this region are to complete and test the wells with very tight deep sands and HPHT operations.
The target reservoir consists of two distinct pay zones, the lower part is G formation which consists mainly siltstones, and the upper part is cleaner R sandstone. Total thickness of primary target zone of interest is more than 200 m with average permeability of less than 0.1 mD. Open hole log indicated water saturation in G formation to range between 20% to 60% while in R formation saturation range was between 40 to 70%. Initial exploratory test showed no significant flow of hydrocarbon therefore hydraulic fracturing program was proposed and planned as the enabler to facilitate production at economic rates from these reservoirs.
Detailed petro-physical and geo-mechanical formation evaluation with Mechanical Earth Modeling, reservoir evaluation using Injection Fall off test and fracture height estimation using Planar 3D models are some of the tools used to ensure a successful stimulation job across a 200 m thick G formation which appeared to have no significant stress contrasts to confine individual fracture treatments. The hydraulic fracturing project workflow includes selecting right perforation strategy, optimizing number of fracturing treatment and minimizing fracture interference. Proper data interpretation, meticulous planning and detailed engineering analyses and design overcome these challenges, which lead to successful hydraulic fracturing completion of all the wells in the campaign with encouraging well production test results and thus confirming the presence and commerciality of hydrocarbons in this field.
This paper details the technical analysis and engineering workflow used as tools for a successful hydraulic fracturing of G and R formation. Design, Execution and Evaluation process used during hydraulic fracturing is also discussed. In the end, lessons learned and recommended workflow to explore similar reservoir in the future have been captured.