PTTC/DOE/RPSEA Gas Shales Workshop Marcellus Shale Hydraulic Fracturing > Arlington Virginia > September 28 th, 2011 > Jordan Ciezobka - GTI
RPSEA Marcellus Gas Shale Project Objective To enhance shale gas production from the Appalachian region and develop technologies to overcome the technical and environmental challenges that prevent the expansion of Marcellus Shale production Source: USGS 2
Project Structure Field Data Acquisition, Integration and Coordination (Gas Technology Institute) The proposed project includes gathering of data and information from the participating producers, publicly available data, field data acquisition including sampling, coring, logging, hydraulic fracturing, fracture diagnostics, and production logging. LBL 3
Hydraulic Fracturing - Diagnostics Hydraulic Fracturing Fracture Diagnostics Effectiveness of hydraulic fracturing based on microseismic imaging (SRV), pumping diagnostics, and production results Quality control of surface and borehole microseismic analysis velocity model calibration, fracture geometry and attributes, SRV comparison, check shots Optimization of hydraulic fracture treatments through examination of created fracture geometry and complexity, coupled with production results 4
Marcellus Shale Play Properties Reservoir Depth 1,500-8,000 ft Thickness 50-300 ft Total Organic Content (TOC) 5.3% - 7.8% Thermal Maturity (Ro) 0.6%-3.0% Average log porosity 5.5% - 7.5% Pressure (psi/ft) 0.42-0.7 Water saturation (Sw) 12% - 35% Gas in place (bcf section) 30-150 Anticipate recovery Factor ~30% Average EUR / Hrztl well (bcf) 3.75 Source: Engelder, 2008 5
Research Site ~3,500 ~3,200 ~4,500 6
Local Setting 7
Marcellus Gas Quality >Dry Gas 1000 BTU >Wet Gas 1300 BTU Source: Penn State University 8
Well Placement 9
Hydraulic Fracturing 10
Hydraulic Fracturing Continued 11
Borehole Microseismic Geophone Array Horizontal Array 8 Shuttles spaced 100 ft apart Array positioned in Well-C Array moved to 5 positions during course of zipper-frac treatments. VSP used for velocity profile & Perforations check shots used to recalibrate velocity model 12
Zipper Frac 1 st Sequence 13
Zipper Frac 2 nd Sequence 14
Zipper Frac 3 rd Sequence 15
Zipper Frac 4 th Sequence 16
Zipper Frac 5 th Sequence 17
Surface Microseismic 1082 stations in the array. They are represented as blue spheres. The array consists of 10 lines radiating away from the well head. Wells A through G are shown in red. Data was acquired with the GSR recording system at 2ms sample rate. VSP used for seismic velocity profile 18
Microseismic Results Borehole Microseismic Surface Microseismic 19
Well-D Production Log & SRV 20
Frac Design Optimization - Normalized Gas Production Rates 21
Pumping Diagnostics Well D Stage 4 Frac Pressure Response Well E Stage 5 Frac Pressure Response Well B Stage 5 Frac Pressure Response Typical Pressure Response 22
Possible Swarm of Natural Fractures 23
Fracture Characteristics Derived from Microseismic Survey Simple Fractures Complex Fracture Network 24
Planned Field Data Acquisition >Production Log After 6 Months Late production contribution from individual frac stages Microseismic event frequency/cloud geometry impact on long term production Effect of condensate blockage resulting in permeability reduction >2 nd Test Site FMI to characterize natural fractures Microseismic imaging Production log 25
Frac Design Comparison Maximum Proppant Concentration (ppg) 4.5 4 3.5 3 2.5 2 Bubble Size = Proppant Weight per Stage (klbs) 340 Eastern PA 384 409 0 1 2 3 4 5 6 7 Location Number Western PA 500 489 401 26
Attempt to Reduce Completion Cost by Reducing Proppant Mass >In 2008 and 2009 major operator experimented reducing the proppant mass significantly by pumping lite fracs in 3 wells in order to reduce completion costs >Reduced the proppant per well to about 600 klbs from a typical amount of about 4.4 mmlbs per well as adopted from previously explored shale plays >Compensated for proppant volume reduction by adding additional frac fluid in order to achieve same SRV Source: SPE 131783 27
Frac Design Summary Average Offset Frac Average Lite Frac Stage Water (gal) 392,700 558,600 Stage Sand (lb) 550,000 100,000 Total Well Water (gal) 3.0 Million 3.4 Million Total Well Sand (lb) 4.4 Million 600,000 >Cemented laterals, pump down plug and perf >Roughly 60/40 ratio of 100 mesh to 30/50 mesh for the offset fracs >No 30/50 mesh in the lite fracs Source: SPE 131783 28
Production Results >Average 8 month cumulative production: Offset Fracs: 641 MMcfe Lite Fracs: 260 MMcfe >Average EUR for the lite fracs is 43% less than the EUR of the offset fracs based on limited production data >History matching shows that the effective fracture half length (Xf) of the lite fracs is 1/10 the length of the offset fractures as a result of major conductivity reduction Source: SPE 131783 29
Thank You! Jordan.Ciezobka@gastechnology.org 30