Presentation on theme: "Exploitation and Optimization of Reservoir"— Presentation transcript:
1 Exploitation and Optimization of Reservoir Performance in Hunton Formation, OKReview of Budget Period IDE-FC26-00BC15125ByMohan Kelkar
2 Partners in Project The University of Tulsa The Department of Energy Marjo Operating CompanyThe University of HoustonJim Derby and AssociatesJoe Podpechan and Jason Andrews
3 Outline Objectives of the project Progress so far Conclusions BP I Future work
4 ObjectivesTo understand the primary production mechanism by which oil is being produced from the West Carney fieldTo develop procedures for extrapolating the production methods to other wells and other reservoirs exhibiting similar characteristicsTo extend the life of the field beyond primary production
5 Tools Used Geological Description Log Analysis Flow Simulation Rate-Time AnalysisLaboratory Data Collection and Analysis
8 Characteristic Behavior Water oil ratio decreases over timeGas oil ratio first increases and then decreases with timeIncrease in GOR when the well is reopened after workoverSome wells exhibit pressure drawdown when the well is shut-inAssociation between oil and water production
10 Presence of FracturesCore photographs indicate the presence of fractures
11 Presence of FracturesHigh permeability, in excess of 1000 mD has been observed at some locationsHigh water rates also indicate the presence of fracturesCommunication between wells has been observedWell test data also indicates fractures
13 Relation Between Oil and Gas Production Wells that produce oil also produce gasOil and gas exhibit the same production trend
14 Relation Between Oil and Gas Production Plot of oil rate vs gas rate for all the wellssuggest the same behavior
15 Limited AquiferReservoir pressure has been declining in the field
16 Limited AquiferWater rate is also declining in the field
17 Bulk of the Hydrocarbon Production is Through Water Zone Some wells have shown good fluorescence but are bad producersThese wells also produce less water
18 Bulk of the Hydrocarbon Production is Through Water Zone
19 Core Descriptions and Analysis Twenty seven wells have been cored, data from twenty two wells was available for this studyCores have been analyzed at Stim LabFourteen cores have been described in detailThree lithologies; limestone, dolomite and partly dolomitized limestone have been identifiedFourteen facies types have been recognizedFour pore types; vug, coarse matrix, fine matrix and fracture have been recognized in each of the three litho types.Results from Conodont studies have been used to demarcate the cochrane and clarita formations
26 Correlation of Core data to Log data Comparison of core derived porosity to log derived porosityMaking of core-log plotsReduction of pore typesUse the vs Ln K relation to generate K values at un-cored wells
45 Correlation of static data to dynamic data Production data for competitor wells was collected from public domainWells were declined at a rate of 50% per year and cumulative production for a six year time period was calculatedPickett plots for each well were compared to the production data.
59 Single Well Numerical Model Production characteristics to be reproduced from numerical modelInitial decline in GORAssociation of oil production with that of water productionDecreasing water-oil ratioIncrease in GOR after the well was shut-in
68 Rate-Time AnalysisEstimate permeability and skin factor for wells using available production dataImprove understanding of West Carney Field which exhibits complex production characteristicsDevelop procedures for estimating in place reserves in the field.
69 Reservoir Model Description Three layer-no cross flowAnalysis should give:3 external radius values3 permeability values3 skin factor values
80 Results Generally, consistent with field observations Wells acid fractured, so negative skin expectedWells drain more than 160 acresOil and Gas layers have much lower permeability than the Water layer
81 Lab Work Methodology CT Scan Wettability using standard Amott wettability testUnsteady state relative permeabilitiesDean Stark analysisCorrelation between wettability and relative permeabilitiesWettability alteration tests
85 Mercury Capillary Pressure 1: Carter , 2: Wilkerson , 3: Mary Marie
86 Correlations As porosity and absolute permeability increase rock becomes more oil-wet.
87 Correlations As rock becomes more oil-wet end point relative permeability increases.
88 ConclusionsReservoir is highly heterogeneous; karst and fractures affect well performanceDual permeability system seems to existFine matrix rock seems to be better connected to the high permeability componentLow recoveries from the coarse matrix and vuggy rock suggests that these are isolated poresDecrease in reservoir pressure and water production confirms a limited aquifer
89 Conclusions (contd) Oil and gas co-exist in the field Electrofacies analysis successfully differentiate between the oil zones and the invaded zonesWells with high proportions of electrofacies # 4 & 5 are good producersWells calculating high oil in place from log data are not necessarily good producers
90 Conclusions (Contd.)Study confirms that the field is highly heterogeneous and wells are in communication with each other through fracturesIt is possible to determine drainage radius from material balance and use automatic type-curve matching to determine permeability and skin.Skin factor results provide a useful tool to determine completion effectiveness
91 Conclusions (Contd.)Hunton rocks are found to be neutral wet to oil-wet.In rocks studied ,oil wettability increases as absolute permeability and porosity increase.The end point water relative permeability increases as oil wettability of rocks increase.
92 Future WorkImprove reservoir and fluid description for history matchingImprove logging analysisInclude multi-phase flow in rate-time AnalysisInvestigate tertiary recovery mechanisms to improve the recoveryConduct technical workshops
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