Presentation on theme: "Preformed Particle Gel (PPG) for Conformance Control Baojun Bai, Yongfu Wu Petroleum Engineering Missouri University of Science and Technology March 23,"— Presentation transcript:
Preformed Particle Gel (PPG) for Conformance Control Baojun Bai, Yongfu Wu Petroleum Engineering Missouri University of Science and Technology March 23, 2009 Missouri Energy Summit 2009
Outline Oil Production Mechanisms Enhanced Oil Recovery (EOR) Targets Preformed Particle Gel (PPG) for Conformance Control Gel Treatments Advantage of PPG Treatments Enhanced Oil Recovery Mechanisms Applications Future Research Summary
Oil Production Processes
Oil Recovery Mechanisms
EOR Potential in the U.S.A EOR Targets Original Oil in Place in USA: 649 Billion Barrels
EOR Potential in the World
The Four Key Issues to be Resolved to Maximize Oil Recovery
Preformed Particle Gel (PPG) for Conformance Control
What is Preformed Particle Gel (PPG) (a) Before swelling (b) After swelling Cross-linked polyacrylamide powder SUPER ABSORBENT POLYMER
Why Gel Treatment Excess water production is the most serious problem to reduce oil production as oilfields are maturing. Improved sweep efficiency has become the most important target to improve oil recovery. Gel Treatments are often the best choice to mitigate channeling through fractures and super-K streaks
What is Gel? Gelant (polymer/monomer+crosslinker +additives) Gel
Gel Treatment to Block/Reduce Water Flow through High Permeability Zone/Streak Near Wellbore Treatment (no crossflow) In-depth Gel Treatment (thick heterogenous layer with crossflow) KLKL KLKL KhKh Gel K h Gel KLKL
Gels Used for Conformance Control In-situ gel systems: Gelant is injected into formation and gel is formed under reservoir conditions after placement. Gelation occurs in the reservoir. Preformed gel systems: gel is formed in surface facilities before injection, then gel is injected into reservoirs. No gelation occurs in reservoir.
A Newer Trend in Gel Treatment is Using Preformed Gels Inherent disadvantages of In-Situ Gel Crosslinking reactions are strongly affected by Shear by pump, wellbore and porous media Adsorption and chromatography of chemical compositions Dilution of formation water Possible damage on unswept low permeability oil zone of in-situ gel
Current Preformed Gel Systems Preformed Bulk Gel: Dr. Seright/NMT, Robert Sydansk Micro Particle Gel: µm-sized particle by Zaitoun et al/IFP. One application in a gas storage well Bright Water ® : Nano particle by Chevron, BP and Nalco Ten plus well pilot tests. Preformed Particle Gel: mm-sized Grained particle, Bai et al, bout 2,000 treatments
PPG Products Size Adjustable: um-mm Swelling Ratio: 30 200 times original Salt Resistance: All salt types and concentrations are acceptable Temperature Resistance: High, to 110 ºC Long-term Stability: more than 1 year below 110 ºC.
Oil Recovery E R =E D ×E A ×E V E R =Recovery Efficiency E V =Vertical Sweep Efficiency E A =Areal Sweep Efficiency EOR Mechanisms of PPG Treatment Biggest Impact – Selective Plugging E D =Displacement Efficiency Some Effect
K h =8.23 D No. Permeability (Darcy) Split of Flow (percent) Oil Recovery ( 98% water cut) Total Oil Recovery Before (%) after (%) before (%) after (%) ） Before (%) After (%) S Experimental Results of Parallel Core Flooding (Vertical Heterogeneity Model) K L =0.54 D
Areal Sweep Efficiency Improvement Before PPG Inj. After PPG Inj. a. Remaining oil distribution in main stream b. Oil distribution at corner – Now lower glass oil drop PPG water MICROMODEL DEMONSTRATION More water diverted to corner after PPG injection 3cm
Experimental Results from Single Sandpack Demonstrates Improved Displacement Efficiency Core No. K (D) PPG Size (mesh) Swi (%) Oil Recovery 1 (%) Oil Recovery 2 (%) Increased Oil Recovery (%) No No “1” refers to oil recovery from water flood before PPG injection “2” refers to total oil recovery from both water flood and PPG treatments
Field Applications About 2000 treatments so far Reservoirs: Naturally fractured reservoirs Reservoirs without initial or hydraulic fractures. Temperature: 30~110 º C Salinity: 2,900 ~ 300,000 mg/L PPG amount: 1, 000 ~120,000 lbs/well, commonly 15,000-40,000 lbs/well.
First pilot in Zhongyuan, SINOPEC The performance of center producer connected with W51-75 and P-72 Increased Oil 29,151 bbl Oil incr. per PPG 0.3 bbl of oil per lbs of PPG Treatment Results
Future Research Swollen particle transport mechanisms through high permeability zones and fractures. Development of nano- or micro-sized swelling rate controllable particle gel. Combination of PPG treatment and other EOR methods to enhance overall oil recovery.
Summary Up to 65% reserve is remained after waterflood. EOR should be considered, and can extract up to additional 25% OOIP. PPG treatment overcome the distinct disadvantage of traditional in-situ gel treatments. PPG treatment is a cost-effective method to improve oil recovery and reduce water production
Acknowledge Financial Support from Research Partnership to Secure Energy for America (RPSEA) under DOE contract Missouri University of Science and Technology