PETROLEUM DEVELOPMENT GEOLOGY WELL TEST

Well Test Objectives Identify and Obtain reservoir fluids; oil, gas & water Determine basic reservoir parametes; productivity (PI), permeability(k), skin (S), initial Resv Pressure (P*) & Resv Temp Well potential & deliverability (gas well) : It may be mandatory to proof field commerciality Boundary & irregular conditions Reservoir (GOC, OWC & Reservoir Limit) WELL TESTING METHODS • HOLE CONDITION: – OPEN HOLE – CASED HOLE • TOOLS RUN IN HOLE : – WIRELINE TESTING : RFT, MDT & DST (IT WAS) – PRODUCTION TEST WITH COMPLETION STRING IN PLACE : DST WELL TESTING SCHEMATIC at Cased Hole Surface Test Equipment Subsea Safety Equipment Downhole Test Equipment & Tool DST & TCP DOWNHOLE TESTING EQUIPMENT Open-Hole Sampling Equipment RDT & RCI are equivalent with RFT/MDT Formation Test Tool (FTT) sample chambers hold 420cc to gallons of reservoir fluid depending on make and model Open hole samples aid production and facility designs and are sometimes used for PVT studies Baker RCI® Halliburton RDT® 1ST GENERATION RFT REPEATED FORMATION TESTER - unlimited pressure survey - to fluid sampling 2ND GENERATION MDT MODULAR FORMATION DINAMIC TESTER - unlimited pressure survey - many fluid sampling (unlimited?) - able to identify fluid type - able to replace(pump out) unrequired fluid sample SCHLUMBERGER DOWNHOLE TESTING EQUIPMENT RFT / MDT Mud pressure Reservoir pressure Build-up pressure Example RFT Record • To identify the reservoir pressure • To identify the fluid content • To estimate the permeability • To estimate the productifity • To define the fluid contact (OWC, OGC and GWC if any) Fluid Contact Determination with fluid gradient from RFT Oil Gra er at 36 nt die W t i/f ps depth 33 OWC water RFT depth pressure /ft psi t0 en di G oil • Clean up (flow) • Shut-in • Main flow (one period or flow-after-flow, flowing test with to different choke size) • Main Build –up (shut-in) Selective Layer Testing 26” 20 ft @ 500’ 17 1/2” 5/8” @ 15500’ 12 1/4” Layer A Layer B 1/2” 7” @ 17690’ [ [psia] psia] Example : 4050 4050 Pressure Testing Result K = 375 mD S = 21 P = 4200 psia Pressure, psia Build up data analysis Sanding Control Test Production Period [[Mscf/D] M scf /D] 45000 45000 Build up period rates 40 40 60 60 80 80 Testing time, hrs 100 100 120 120 Well Productivity IPR plot 3500 1500 Pressure, psi AOFP = 344 MMscf/d CGR = 24.5 STB/MMscf/d Tested gas and condensate rates can be increased to 125 MMscf/D and 3100 BPD Gas Rate, Mscf/d 50000 1.5E+5 2.5E+5 2.5E+5 3.5E+5 Testing Risk Factors ̇ Layers communication due to poor cement bond ̇ High pressure and temperatures (over 350°F) ̇ Pressure and fluid loss through packers ̇ Annulus-tubing fluid communication ̇ Water coning or sanding ̇ Layers crossflow THE ROLE of WELLSITE/DEVELOPMENT GEOLOGIST (DG) in WELL TESTING OPEN HOLE TESTING CASED HOLE TESTING with RFT/MDT with DST DG Propose/selects the testing/perforation sand, interval and depth Estimate the reservoir fluid contents and it’s static pressure Provide the reservoir rock parameter for testing analysis such as lithology, porosity and permeability if any (from log, or qualitative) Stop the testing when unsafe operation Testing Engineer (TE) decision Decide testing duration TE decide flow & shut-in periods TE also selects choke size for flow testing Select taken fluid sample TE decide fluid sampling methods And responsible for fluid sample handling As Operation Witness will validate & analyse the result TE is prime Operation Witness and will validate & analyse the testing result DG & TE will be along selecting the perforation method PERFORATION THROUGH CASING GUN å Hyperjet/HSD(high shot density) THROUGH TUBING GUN å Enerjet TCP (Tubing Conveyed Perforation) PERF At Net pay Define the perforation intervals at porous zone & hydrocarbon zone (pay zone Evaluate and prepare the perforation design such as gun type, size, SPF (shot per ft), Spacing (angle between two shots), charge/explosive type; penetration deep and entrance hole Perforation environment (fluid type in the hole); using mud or brine water or special completion fluid, under/over balance Witness the gun loading, correlation, shooting result (whether all charges exploded or not) å “SAFETY FIRST” [...]... ROLE of WELLSITE /DEVELOPMENT GEOLOGIST (DG) in WELL TESTING OPEN HOLE TESTING CASED HOLE TESTING with RFT/MDT with DST DG Propose/selects the testing/perforation sand, interval and depth Estimate the reservoir fluid contents and it’s static pressure Provide the reservoir rock parameter for testing analysis such as lithology, porosity and permeability if any (from log, or qualitative) Stop the testing... Period [[Mscf/D] M scf /D] 45000 45000 Build up period rates 40 40 60 60 80 80 Testing time, hrs 100 100 120 120 Well Productivity IPR plot 3500 1500 Pressure, psi AOFP = 344 MMscf/d CGR = 24.5 STB/MMscf/d Tested gas and condensate rates can be increased to 125 MMscf/D and 3100 BPD Gas Rate, Mscf/d 50000 1.5E+5 2.5E+5 2.5E+5 3.5E+5 Testing Risk Factors ̇ Layers communication due to poor cement bond ̇ High... flow (one period or flow-after-flow, flowing test with 4 to 5 different choke size) • Main Build –up (shut-in) Selective Layer Testing 26” 20 ft @ 500’ 17 1/2” 9 5/8” @ 15500’ 12 1/4” Layer A Layer B 8 1/2” 7” @ 17690’ [ [psia] psia] Example : 4050 4050 Pressure Testing Result K = 375 mD S = 21 P = 4200 psia Pressure, psia Build up data analysis Sanding Control Test Production Period [[Mscf/D] M scf /D]... testing when unsafe operation Testing Engineer (TE) decision Decide testing duration TE decide flow & shut-in periods TE also selects choke size for flow testing Select taken fluid sample TE decide fluid sampling methods And responsible for fluid sample handling As Operation Witness will validate & analyse the result TE is prime Operation Witness and will validate & analyse the testing result DG & TE will ... Layers crossflow THE ROLE of WELLSITE /DEVELOPMENT GEOLOGIST (DG) in WELL TESTING OPEN HOLE TESTING CASED HOLE TESTING with RFT/MDT with DST DG Propose/selects the testing/perforation sand, interval... WIRELINE TESTING : RFT, MDT & DST (IT WAS) – PRODUCTION TEST WITH COMPLETION STRING IN PLACE : DST WELL TESTING SCHEMATIC at Cased Hole Surface Test Equipment Subsea Safety Equipment Downhole Test. .. Resv Temp Well potential & deliverability (gas well) : It may be mandatory to proof field commerciality Boundary & irregular conditions Reservoir (GOC, OWC & Reservoir Limit) WELL TESTING METHODS