OPTIMIZING HYDRAULIC FRACTURE DESIGNS USING GEOMECHANICAL MODELING TO OBTAIN THE OPTIMUM FIELD DEVELOPMENT AND PRODUCTION IN K-FIELD

摘要

Commercial oil rates are not easy to attain inrnreservoirs with permeability less than 5 mD. Thernchallenges in the K-Field are low permeability withrnhigh reservoir rock strength and it is categorized asrna high temperature reservoir (320 degF).rnSelection of the best development scenario in the KField,rnlocated onshore in the Malacca Strait Block,rnIndonesia has been undertaken continuously sincern2004. Development was started using a vertical wellrnwith a conventional, perforated cased-holerncompletion. The development scenario wasrncontinued by drilling highly deviated wells usingrnslotted liner completions to improve productionrndeliverability. In 2007–2011, seven wells wererndrilled with hydraulic fracture-stimulation , whichrnresulted in improved production results. The oilrnproduction increased by a factor of four comparedrnwith the best performing unstimulated wells, withrnan average initial rate of 359 BOPD and oilrncumulative of 264 MSTB. The fracture stimulationrnhas been the most successful technique applied torndate to maximize the oil rate and recovery per well,rnwith an 86% success ratio.rnAlthough hydraulic fracturing is not a newrntechnique in fields with low permeability inrnIndonesia, the integration between fracturing designrnand geomechanical modeling is a relatively newrnconcept being adopted. One of the challenges withrnhydraulic fracturing in Indonesia is understandingrnthe stress anomalies due to complex geologicalrnsettings and applying this data to optimize the fracrndesign.rnThe fracture geometry strongly depends on thernreservoir characteristics and geomechanical properties. It is essential to have detailed knowledgernof petrophysical and geomechanical properties ofrnthe reservoir and surrounding formations.rnThe success of the key fracture stimulation in the KFieldrnwas a tailored data acquisition program,rnfollowed by petrophysical analysis andrngeomechanical modeling, resulting in well foundedrnfracture designs. For every fracture treatment, arnMechanical Earth Model (MEM) was constructed,rnbased, in particular, on high quality full waveformrnsonic data from a recently introduced sonic tool,rnwhich provided unique geomechanicalrnmeasurements. The MEM gives information tornoptimize our hydraulic fracture-stimulation,rnespecially for initial design and treatment design.rnAll the detailed knowledge has been used tornincrease our confidence for hydraulic fracturingrnstimulation. At this time, the study of hydraulicrnfracturing is continuing with improvements tornobtain the optimum field development andrnproduction in the K-Field.