SQUEEZING THE BAKKEN: SUCCESSFUL SQUEEZE PROGRAMS LEAD TO SHIFT CHANGE IN BAKKEN SCALE CONTROL

Transcription

1 SQUEEZING THE BAKKEN: SUCCESSFUL SQUEEZE PROGRAMS LEAD TO SHIFT CHANGE IN BAKKEN SCALE CONTROL WILLISTON BASIN PETROLEUM CONFERENCE KEVIN SPICKA, PHD May 3,

2 Outline Background Product Qualification Squeeze Programs Field Results Summary 2

3 Bakken Production Can Have Challenges 3

4 Bakken Conditions Can Be Challenging Impacts scale inhibitor stability Cation mg/l Barium Ba²+ 18 Calcium Ca² Iron Fe²+ 300 Magnesium Mg²+ 847 Potassium K Sodium Na Strontium Anion Sr² mg/l Bicarbonate HCO₃ 600 Chloride Cl Sulfate SO₄² 540 ph Calculated, STP 6 to 7 Can be >30,000 mg/l Impacts scale inhibitor solubility Impacts scale inhibitor performance Environ. Sci. Technol. Lett. 2016, 3,

5 Lack of Scale Control: Chemistry or Application? Lab qualified products Undeniable field observations Plugged sand screens Stuck pumps Solids on tubing/rods Field & lab ID solids as CaCO 3 Product applied continuously down annulus (as far upstream without squeezing) 5

6 Let s Talk This Through It s the chemical! Can we discuss this over lunch? It s the application! 6

7 Squeeze Applications Commonly used in conventional wells Placement of scale inhibitor within the reservoir Scale inhibitor adsorbs to the rock and returns with produced water Squeeze type applications can be used for other chemistries: Corrosion Paraffin Asphaltenes Production Enhancement 7

8 Production Enhancement Application PE PATENT PENDING Alter wettability in tight oil systems to improve oil recovery Comprehensive fluid-rock lab work to understand compatibility and recovery Inject optimized PE formulation below fracture pressure (compatible with completion fluids) 10,000 Optimizing the PE Formulation is Critical to Maximize Effectiveness Optimized PE Formulation 2 PE Formulation 1 Fresh Water Single Well Enhancement Oil Rate (bbls/day) ~ 25% Incremental EUR 10 Apr 12 Aug 13 Dec 14 May 16 Sept 17 Feb 19 Jun 20

9 Scale Squeeze Chemical Product Qualification Brine compatibility Thermal stability Scale inhibition testing Core flood testing Formation damage Retention/release of SI Product A B C D E Chemistry Type Polymer Phosphonate Phosphonate Phosphonate Phosphonate Cation mg/l Barium Ba²+ 18 Calcium Ca² Iron Fe²+ 300 Magnesium Mg²+ 847 Potassium K Sodium Na Strontium Anion Sr² mg/l Bicarbonate HCO₃ 600 Chloride Cl Sulfate SO₄² 540 ph Calculated, STP 6 to 7 9

10 Brine Compatibility Qualification Product A (polymer) 90% 75% 50% 25% 10% Product E (phosphonate) 90% 75% 50% 25% 10% Product AX BX C D E Chemistry Type Polymer Phosphonate Phosphonate Phosphonate Phosphonate 10

11 Dynamic Scale Loop Test 11

12 Dynamic Scale Loop Test 230 o F 1000 psi Cation mg/l Barium Ba²+ 18 Calcium Ca² Iron Fe²+ 300 Magnesium Mg²+ 847 Potassium K Sodium Na Strontium Anion Sr² mg/l Bicarbonate HCO₃ 600 Chloride Cl Sulfate SO₄² 540 ph Calculated, STP 6 to 7 Taking Product E Forward 12

13 Dynamic Scale Loop Test Aged Product E Brine compatibility Scale inhibition performance Thermal Stability 13

14 Core Flood Test Evaluates suitability of squeeze package Permeability to oil/brine Reduced permeability indicates formation damage Scale Inhibitor in flowback Adsorption/desorption isotherm 14

15 Crushed Core Core Flood Test Crude Oil Permeability Scale Inhibitor Return Flow back profile shows similar pressure when compared to the Pre Treatment stages No Formation Damage Recorded Product E met all criteria for use in a Bakken scale squeeze 15

16 Squeezing Horizontal Unconventional Wells How do we want to do this? Protect the pump, get the squeeze closer to the heel Protect the perfs, displace through the whole lateral Can we get chemical where it needs to be without special equipment? Can we use the same models as we do for conventional wells? 16

17 Two Customer Requested Design Approaches One 500 BBL Frack Tank Based on previous squeeze 25 BBL Preflush 125 BBL Main Pill 350 BBL Displacement/Overflush Shut in 2 days Full Wellbore Squeeze Design Used Squeeze9 to take traditional design approach, later used Place-iT BBL Preflush BBL Main Pill BBL Overflush Shut in >1 week 17

18 Well Parameters Well Total Vertical Depth (ft) Total Well Length (ft) Fracture Stages Barrels Oil/Day Barrels Water/Day Squeeze Date A /27/2014 B /27/2014 C , /19/2015 D /29/2015 E /7/2015 F /6/2015 G /26/2015 H /14/

19 Simple Scale Squeeze Application 19

20 Field Results 20

21 Post Squeeze Production Numbers 21

22 Post Squeeze Equipment Observations Clean sand screens Pumps operating It was the application! And we thought it was the chemical s fault! Application makes a difference! Tubing/rods clean 22

23 Optimized Future The Key is Model Software Well Current Design Life Squeeze Life (Days) 50% Scale Inhibitor Concentration 200% Scale Inhibitor Concentration Current Design Life Squeeze Life (Days) 50% Overflush 200% Overflush B > C > D >

24 Summary Best in class Bakken scale squeeze inhibitor identified Horizontal, unconventional wells can be effectively scale squeezed with the correct product Scale squeezes do not require special application methods (i.e. coiled tubing) Post-squeeze production indicates no formation damage Squeezes lasting >2 years Modeling with newly developed software suggests diffusion is a key mechanism New scale squeeze designs based upon modeling are being implemented to ID optimal scale squeeze treatments and validate model 24