Open-Ended Control Challenges in the Oil Service Industry

Transcription

1 Open-Ended Control Challenges in the Oil Service Industry Karlene Hoo, PhD Chemical Engineering Professor Montana State University Jason Dykstra, PhD Chief Technical Advisor Halliburton Corporate Research

2 Global Megatrends and Drivers Population growth continues Especially in developing countries Source: Population Reference Bureau

3 Global Megatrends and Drivers

4 Energy Usage For Next 2 Decades Source: U.S. DOE/EIA International Energy Outlook 2011

5 July 4, 2016 Estimate of Oil Reserves Rystad Energy is an independent research group in the oil and gas industry

6 Unconventional Resources Heavy Oil Shale

7 World Energy Trends The next trillion barrels will be Harder to Find Harder to Access and Produce In Smaller Accumulations More Costly Produced with Fewer Experienced Resources Exploration Development Production

8 Technology Challenges 1 Higher Pressure/Temperature 2 Knowledge, Depth, Accessibility, Power 3 Hostile Downhole Environments 4 Telemetry, Communication Systems 5 Automation and Control Systems

9 Well Life Cycle Exploration Well Construction Completions Production Abandonment

10 Drilling : The problems are getting more challenging and the solutions are getting more valuable Drilling a well faster and cheaper With a high quality wellbore

11 The Challenge in Building a Drilling Control System Mud Pulse communication, travels at the speed of sound in drilling mud at 2-30 bits/sec Large sensor array and the surface and the wellbore end in the bottom hole assembly, but nothing in-between Dynamic modeling is difficult, in particular the rock/bit interaction which is the source of the detrimental vibration Many different systems to consider, and many different environments Formation sensing: Gamma ray, Resistivity, Acoustic calipers and rock mechanics, Neutron, Nuclear magnetic resonance, and others Accelerometers: a x, a y, a z Gyroscopes: a θ, a φ, a ψ Strain gauges: σ x, σ y, σ z

12 Challenge of Deep water drilling Challenges: High Temperature High Pressure (HPHT) Harsh drilling environment Long time delay for mud pulse data transfer / high cost for other methods High cost for well construction and increase in cost of poor quality Drill pipe vibration disturbance to system, accelerate the fatigue of material, hard to measure is deep wells Opportunities: Robust control hardware and software under HPHT Automated well health monitoring and fault detection under limited data access with large time delay Distributed control to overcome limited communication and large time delay

13 Directional Drilling Systems Point the Bit directional control Bent Sub Formation Sensing Downhole Motor

14 Directional Drilling Systems

15 WHIRL

16 Stick-Slip

17 Drilling Optimizer ROP Drilling Optimization Rig control Bit Wear Dynamics Path optimization command path uncertainty Override Path BHA control sensor Update predicted force and position BHA model

18 Full Drilling Optimization Includes vibrational map in operational space ROP Model Wear Model Optimization produces command vector as a function of time. This includes tripping points and bit types. Available Bit types Tripping points becomes part of optimization ROP Model ROP Model Wear Model Wear Model Bit model from wear estimator Wear model updated from actual performance WOB RPM RATE TARGET BIT min cost Where Changing tripping points change acceptable wear rates and cost wear wear max Other Constraints: 1. WOB < max 2. RPM < max 3. No bit bounce 4. No bit whirl 5. Minimal Balling 6. Bit Temp. < Temp. max

19 Hydraulic Fracturing US patent on matrix acidizing Dow Chemical Co discovers that downhole fluid pressure can crack and deform rock formation First experimental well Hugoton Gas Field, Kansas First commercial hydraulic fracture Other application areas: Tunnel and dam construction Water well development Environmental applications Acid dissolves part of the fracture face to create short fractures that are highly conductive channels

20 Europe International Shale Plays Australia Middle East Asia

21 Oil and Gas Production About 35 to 40% of all currently drilled wells are hydraulically fractured About 25 to 30% of total U.S. oil reserves have been made economically producible by the process. Tight gas sands and shale reserves Both oil and gas 503 to 1500 TCF Low permeability Requires fracturing USA Shale Plays

22 Hydraulic Fracturing Equipment Blender Control room Data bases High-power pumps Custom designed Purpose built Transport/Store/Deliver

23 Hydraulic Fracturing Process Plug (special designed shaped charges): placed at the desired stage in the well bore Perforating gun is lowered into the casing Electrical current sets off a charge that shoots small holes through the casing and cement. As materials are pumped downhole, fractures are created MHF: wing length 1000 ft width at wellbore 0.5 in Sliding sleeve: multi-stage fracture efficient

24 Clean fluid or pad (usually water) is pumped into the well at a rate greater that the fluid loss rate to the formation Pad provides sufficient width for the proppant to enter the fissures Stage 1: Pad High pressure gradient: formation breaks and early fracture growth expose new formation to the injected fluid

25 Solid particles are pumped as a slurry or suspension to prop open the fracture once pumping ceases Cheap proppant: sand Fluid: water-based polymer solution (guar, hydroxypropyl guar), aqueous foams, gelled hydrocarbons, Additives: emulsifiers, antifoams, stabilizers, emulsifiers, ph control, surfactants, buffers, bacteria control, Stage 2: Proppant

26 Multi-stage Fracturing More flexibility Manage production Complete the well Improve well performance Deliver more effective completions

27 Shut-in Fracture walls close on propping agent Flow-back of proppant to the wellbore Clean-up of fluid system to allow oil/gas to flow Pressure curves in hydraulic fracturing

28 Fracture Propagation Model Fracture Treatment Design Mini-fracture data In-situ stress profile Formation properties Fluid-loss characteristics Reservoir model & fracture propagation model Optimum economic benefit $ Revenue Less $ Cost Fracture Length Treatment Volume $ Cost Reservoir Model

29 Challenges Layers of rock providing dissimilar confining stresses Changes in magnitude and/or orientation of the in situ confining stresses Effects of shear & temperature on fluid rheology Transport of suspended proppant particles into the fracture Fracture recession and closure Rapid geometric changes in one region as fractures extend into other lower stress zones Leak-off of fracturing fluid from the fracture to the surrounding rock

30 More Challenges Fluid system Non-damaging to the rock Able to transport proppant efficiently High flow capacity Long term fluid loss Viscosity/temperature Pressure differential Rock permeability, porosity Effective viscosity: controls the internal pressure Proppant Particle size distribution Roundness & sphericity Acid solubility Turbidity Crush resistance Less dense than water Stronger than diamond Cheaper than dirt Readily available

31 Uncertainty Current Practice Fixed fracturing plan Blind operation Decision making Fracturing plan Emerging technologies Advanced instrumentation (fiber optics, microseismic monitoring Real-time automation system Measurement filtering State/parameter estimation Optimize fracturing plan Automate treatment adjustment Data analytics for job learning Fiber optic measurements DAS, DTS Microseismic monitoring

32 Well treatment schedule "Open-loop Approach Planned using expert advice Physics-based models (computing intensive) Close-the-loop Approach

33 Hydraulic Fracture Automation Controller Surface equipment Fiber optic model measurements Microseismic monitoring Fracture and sand model Dynamic modeling of surface equipment and fracturing processes with closed-loop correction Incorporate microseismic and fiber optic technologies Optimal decision making Learning system Self learning from previous data Database

34 Fracture Model Aim Estimate the fracture state over time Predict final propped fracture conditions Components Fracture geometry propagation Fluid flow and leak-off rates Suspended proppant transport Bank formation due to proppant settling Shut-in process Reservoir stimulation, 18. Chichester: Wiley, 2000.

35 Continuity of mass Fundamental Principles Momentum conservation Linear elastic fracture mechanics (LEFM) Numerical Challenges Issue 1: Nonlinearity near fracture tip Solution: Smaller elements in this region Issue 2: Fracture length increases with time Solution: Moving mesh

36 Fracture Closure

37 Control of the Fracturing Process

38 Control of the Fracturing Process

39 State Estimation

40 Quadratic Adaptive Dynamic Matrix Control Subject to: physical limits (states, actuators) linear step response model

41 Control Framework

42 Before Shut-in 10L/s fluid loss, 300 s from start of pad Fracture Length Fracture Width Proppant bank height

43 Effective frac vol Ref: 6.52 W/O control: 2.96 Control: 6.20

44 Microseismic Interpretation TECHNOLOGIES APPLIED Estimation of Fracture Geometry & Proppant Machine Learning State Estimation Expert Systems DistributionModel-Predictive Control Robust Optimization Observation Well Model Selection & Control p(m 1, t) p(m 2, t)

45 Acknowledgements Graduate Students Qiuying Gu Vikram Shabde Daguang Zheng Alejandro Gonzalez-Flores Yingying Chen Eric Vasbinder Zhenhua Tian Stanislav Emets Texas Tech University Uzi Mann, Ph.D. Shameem Siddiqui, Ph.D. PCOC members Halliburton

46 Thank You