Modular Dynamic Tester (MDT) The Optimum Tool for Evaluation of Exploration Wells Ahmed Dawoud Cairo, Dec. 15', 2016 ‘Anmed Dawoud Modular Dynamic Tester, MDTModular Dynamic Tester, MD Q It is a Schlumberger bottom hole Formation Tester tool Q MDT isa very useful tool.in exploration wells following evaluation of Open Hole Logs and Mud logging. Q Several open hole zones can be tested and sampled in one run ings optimize production testing program with drilling rig on site QO All testing and:sampling components and sensors can be run in one.configuration QO MDT is designed and capable to perform the following: > Measure formation pressure > Collect representative reservoir fluid samples > Perform a mini Drill Stem Test (DST) > Perform a mini Facture test > Perform a vertical interference test.(VIT) QO There are two types: Open Hole and Cased Hole MDT tools ‘Anmed Dawoud Modular Dynamic Tester, MDT 2Summary of Applications by Open Hole MDT Q Optimum in Exploration wells where several discovered reservoirs Pressure pont probe can be tested in the EE Miiction” same run. Pressure : Observation O Ithelps to optimize the bee production testing Permeability program and eliminate ae ; Packer Module tisk of Open Hole DST. for Mini DST, Q The collected single and Mini phase samples would Fail be more representative than other sampling techniques for PVT studies ‘Anmed Dawoud Modular Dynamic Tester, MDT 3eb un |i MDT Configurations EQMDgRmeam in ee Electic Electric Electric Electric ‘Electric Sample Pumpout Pumpout Pumpout Pumpout Hydraulic. ‘Sample. ‘Sample ‘Sample ‘Sample OFA* Optical Single probe Packer Hydraulic Fluid Analyzer Mutisample module (a) (b) ‘Single probe Hydraulic OFA module (c) Single probe Hydraulic All testing and sampling components and sensors Can be run in one configuration using TLC technique for job cost (d) Single probe optimization following evaluation of well trajectory and open hole and mud system (e) conditions ‘Ahmed Dawoud Modular Dynamic Tester, MOT 4MDT Configurations and Testin = nster a Ra QO Pre-test pressure points > Formation pressure (probe technique for large number of points) > Fluids pressure gradients » Fluid contacts Q Dual Packer » Fluid identification (Resistivity and or Optical Fluid Analysis) Fluid sampling (several sampled locations, more than 30 reservoir fluid samples for PVT studies, high pressure nitrogen to maintain the samples pressure above the saturation pressure at surface conditions ) Q Multi-Probe/Dual Packer > Vertical Interference testing (K,, determination) > Mini DST (fluid identification/sampling/pressure) > Mini Fracturing (define fracture pressure gradient) ‘Anmed Dawoud Modular Dynamic Tester, MDT 5MDT and Main Functions Formation Pressure and Fluids Contacts 9) NOT COMMUNICATION WITH THE RESERVOR soe ete Ge pan | e 2 coc E coo = = Single Probe __MultiProbe "Dual Packer & ot 0.32 peilft © 700 FWL 5 Mini-DST 046 pevtt\ water Pressure and Derivative Pressure (psi) Fluid Identification Prior Sampling eng ae ‘Anmed Dawoud atinQuick-Silver Probe (Focused Extraction Probe) : Q Quicksilver probe technique for fluid sampling: Q The inner port is to ensur pumping out the reservoir fluid into the Sampling cylinders. QO The annular guard port is: to pump out the mud Bete filtrates surrounding the inner port thus prevent contamination of the reservoir fluid. O The advantage of this technique is reducing the pump out time for clean samples (Rig Time) Sanping pot Arosa guard pot Fuoter pas (SPMC = Single Phase Multi-sample Chamber). ‘Anmed Dawoud Modular Dynamic Tester, MDT 7Saturn 3D Radial Probe QO Efficiently can perform pressure tests in low mobility formations (as low as 0.01 mD/cp) Q It includes four self sealing section ports at 90° intervals against the borehole wall to pull. reservoir fluid circumferentially Q Applications: » Formation fluid sampling > Down hole fluid identification and analysis » Formation pressure measurement ‘Anmed Dawoud Modular Dynamic Tester, MDT 8Saturn 3D: Inflating the drain assembly Self-seals the elliptical ports of the Saturn 3D radial probe to the formation to quickly establish and maintain flow through The industry's largest surface flow area of more (e) than 79 in?. (a) (b) () ~~ (d) 6:0 0 OF} - Probes’ definitions and sizes =e ) > C ered rary Pere cena) for (@) Standard . Pressure (>) Large Diameter 0.85 Points/Sampling (©) Quick-silver focused 1.01 extraction (6) _Extra-arge diameter 2.01 eee (e) _ Biptical Probe 8.96 (f) Saturn 3D Radial 79.44 ‘Anmed Dawoud Modular Dynamic Tester, MDT 9The Dual Packer Module Q The Packer Module is composed of two inflatable packers to test an open-hole interval of 3ft long in between. Well bore mud is used to inflate the two packers Q The flow area of the open hole isolated by the two packer elements (from top and bottom) helps to minimize pump out time that has a considerable cost impact (rig time cost). Q «Itis optimum for fluid sampling, Vertical interference test for k, testing, min fracture test, and Drill Stem Testing (DST) Q The pumped out reservoir fluid goes through a Fluid Analyzer to identify type of fluid, % water and or free gas before sampling Q The packers rubber elements is the weak point in the MDT as it might get damaged across hard rock in bad hole condition forcing to pull out of hole for replacement ‘Anmed Dawoud Modular Dynamic Tester, MDT 1 0‘ ; ib 1.1) Measuring formation _2=. pressure ae QO ~Formation pressure is measured using the standard or large diameter probe (can be measured as well using any of the other probes during the probe applicatione.g. sampling) QO The pumped out reservoir fluid is very small (maximum 20 cm?) just to create a low pressure areavat the probe setting depth. UO Measuring of formation pressure depends mainly on the mud cake on the wall of the wellbore where a probe is set so pressure equalization at the tested point would be indicative to reservoir pressure but not mud pressure in the wellbore Q Minimum of three successful pressure points are needed to. define fluid pressure gradient of a reservoir fluid (Gas, Oil, or Water) Q Sampling pressure points are selected following interpretation of the open hole logs across clean formation and good hole condition to ensure good sealing during testing inf & ‘Anmed Dawoud Modular Dynamic Tester, MDT 1 11.2) Formation Pressure Measurement CE Tre Q Probes and Packer modules can be spaced out at surface’ to meat the MDT job objectives Q Probes are as set at the selected depth and pushed against the borehole wall providing full sealing from the mud system pressure : Q Reservoir fluid is pumped out from the reservoir j L (maximum volume pumped out is 20 cm) to. create low pressure area and equalize with continuous phase in the reservoir (Gas, Oil, or water) after stopping the pump then equalized pressure is measured _ otPresore Prove Q The pumped out flow rate is directly a’ Pressure Build Up related to the rock permeability em?) Q Analysis of each pressure point help to’ PON mee Pressure calculate mobility (k/,1) which is Weibrd ta Pressure indicative to tested rock permeability §$_ ———_—_____- Measured Pressure ‘Anmed Dawoud Modular Dynamic Tester, MDT 1 2- aa Z 1.3) Formation Pressure Pointsx Pressure fluid gradient of the different fluids’ phases > Fluids contacts in the reservoir (GOC, GWC. and FWL) > Specific gravity of the different fluid phases based on the calculated pressure gradient Depth, TVD ss ‘Anmed Dawoud Modular Dynamic Tester, MDT 1 31.4) Anomalies of MDT Formation Pressure Points Formation Pressure QO Supercharged pressure points usually experienced in tight formation (low permeability) due to equalization with the pressured mud filtrate zone rather than the continuous flowing phase of the. reservoir fluid. Q Failure of the mud cake to sustain and isolate the formation pressure from the mud pressure is another reason QO Under-pressure points usually attributed to short time of pressure build up that did not reach the reservoir pressure ‘& Pressure not stabilized X Successful points oO ae charged points +——— Depth, TVD ss ‘Ahmed Dawoud Modular Dynamic Tester, MOT 1 42.1) Optical Fluid Analyzer, OF AES. on Q OFA includes an absorption spectroscopy to detect and analyze liquids and optical reflection measurement to detect gas - uid (or Live) Fluid Analyzer, LFA, to ifferentiate between Oil and Water e eran Fluid Analyzer, CFA, to differentiate between Gas, Oil, and Water and — estimate GOR and gas composition -_- = Q OFA\is to help taking decision to: Uguid Fluid Analyzer, LEA > Differentiate between the different fluids (water, Oil from oil base mud, Gas, and reservoir Oil) > Decrease the pumping out drawdown pressure to dissolve the liberated gas back in one phase Sperone > Divert the single phase hydrocarbon to the aera sampling cylinder at sampling pressure Composition Fluid Analyzer, CFA foe than the bubble point pressure for. VT studies ‘Anmed Dawoud Modular Dynamic Tester, MDT 1 5ese LFA Example ———| Le LFA-Gas and Water Example Log ‘Anmed Dawoud Modular Dynamic Tester, MDT2.3) Specifications of MDT Sampling Bottles MRSC 1 or 2.75 gal No 170 deg.F No MPSR = 450 cc No 200 deg.F Yes SPMC__ 250 cc 400 deg.F Yes MRSS __ 600 cc Yes 400 deg.F Yes Q Sampling bottles are added to the MDT configuration. Q Pumping out of mud filtrates and reservoir hydrocarbons fluids is conducted at continuous monitoring of the flow stream using OFA (LFA and or CFA) until minimum water level is reached (10%-20% maximum) QO) Pumping pressure is controlled to ensure no'free gas in the flow stream (sampling pressure > bubble point pressure) Q) Successful single phase hydrocarbons fluid samples are directed to selected sampling bottle that secured closed at bottom.3) Mini Drill Stem Test, DST Q Mini DST by MDT is more safe and controlled than classical DST Q) It helps to calculate the formation parameters (permeability, and Reservoir pressure) and collect representative reservoir fluid samples for PVT studies Q As long time of pumping out is needed, DST in most cases is conducted using the dual packer or high flow rate probe Mud Pressure, pn Pump out period Pressure Transient Test Analysis of the Pressure Build Up period ‘Anmed Dawoud Modular Dynamic Tester, MDT4) Mini Fracturing Test Q Mini fracturing test replaces surface step rate test that defines the bottom hole fracturing pressure of a formation and design:the maximum well head injection pressure to avoid fracturing the formation during injection QA Sa nad ayarge flow ee probe is used to pump in a , successive increased rate and 4 Filtered mud from the well BHIP until formation fracture bore mud is used-as occurs injecting fluid j OQ The dual packer would Q The fracture is well controlled i in the injection area and would hae be kept uninfigied have a very limited vertical extension that would not communicate with overlaying or underlying reservoirs. Pumped in Rate, co ‘Anmed Dawoud Modular Dynamic Tester, MDT 1 9g- \ ( 5) Vertical Interference aa Test, VIT = Q =VIT as part of MDT program optimization can be carried out during fluid sampling or " DST where considerable long time is taken Obseniation Probe, until a clean representative reservoir oil APo sample is pumped out Mud Pressure, Pin Q The dual packer and or large flow area probe. (active pumping out point) and a standard probe (pressure observation point) are spaced.out at surface across the target interval of the VIT before running in with the MDT. Q The larger the observed drawdown wt pressure response seen by the observation probe (Ap,) would be indicative to better vertical permeability across the selected interval Q Analysis of both drawdowns would result in calculated horizontal permeability in the active point (k;,) and vertical permeability across the target interval (k,,) as well as ‘Tene reservoir pressures at the two points & oe oes a Dense layer Active Dual Packer or Probe, Ap, Mud Presture, Pn Pressure ‘Anmed Dawoud Modular Dynamic Tester, MDT 2 0Important Sensors Q GR: Gamma Ray is always included in the tool configuration for necessary depth correlation for the selected points. Q Resistivity: Resistivity is used to differentiate between mud filtrates’ water and formation water. Pumping out of deep mud filtrates invasion would take long time before receiving the formation fluids. A wrong decision might be taken to terminate a test on misinterpretation of the pumped out water as formation water missing hydrocarbons bearing formation. Q pH: Mud filtrates’ water would have pH of 7+ compared to formation water that would have pH less than’6. This helps to differentiate between the two waters. QO HS: This sensor helps to detect H2S in the reservoir fluid so proper composition corrections could be considered in the PVT studies of the collected samples. ‘Anmed Dawoud Modular Dynamic Tester, MDT 2 11.1) Recommended MDT Running Procedure Q Running MDT must consider its expensive cost including rig time Q Depth charge and pene are main actors controlling the MDT cost and charges of the different components and sensors Q). Maximum value rom the MDT should be considered if decided to be run i,e, maximize information from MDT acquisition Q_ Ensure suitable hole condition and mud system to avoid tool sticking and or plugging of the probes ports that would force to pull out of hole Q MDTis soul eon sbay of a Reservoir Engineer who would have to be on top of the job with Schlumberger Logging Engineer Q The responsible Reservoir Engineer have to check the ering reports and mud losses and overbalance to decide if reported strong mud invasion due to losses or excessive mud overbalance could mask the required data (formation pressure, fluid identification, and sampling). A decision might be taken to cancel the MDT job if such conditions reported. ‘Anmed Dawoud Modular Dynamic Tester, MDT 2 21.2) Recommended MDT. === Running Procedure on Q The responsible Geologist is to mark different formations on the open hole logs for necessary interpretation QO The responsible Petrophsicist is to make interpreted open hole logs available with necessary environmental corrections for selection of the pressure and sampling points. QU The responsible Reservoir Engineer is to write down the MDT program defining: > Tool configuration (probes, PKR, sensors, and number of sampling cylinders) » Pressure points (say 5 points in each fluid to define its fluid gradient) » The number of fluid samples from each sampling point (three from each for proper quality check and selection of most representative sample for PVT study) > The recommended sensors to be added (pH, H3S, Resistivity) Drilling to circulate the well bottom up with fresh clean mud to avoid plugging ie probes and the MDT pump by the suspended solid in the old mu X ‘Anmed Dawoud Modular Dynamic Tester, MDT 2 31.3) Recommended MDT Running Procedure Q Decide of the probe size for acquisition of pressure points taking into. consideration: » Good permeable point could-be used for pumping out for fluid identification and sampling. Thus a big flow area probe would help reducing the pump out time > Alternate prereure points In vicihy of each selected point in case tight formation is experience Q All pressure points to be acquired during running in Q Fluid identification, sampling, VIT, and or mini DST where dual packer module would have to be used should be made while pulling out of hole to avoid damaging the rubber element of the packer Q Most important, the responsible Reservoir Engineer would have to be on top of the job forany actions might be taken with changing any of the program steps ‘Ahmed Dawoud Modular Dynamic Tester, MOT 2 4Thank you