East Texas Cotton Valley Sands: The Transmogrification of Historical Vertical Development to Horizontal Exploitation

Transcription

1 East Texas Cotton Valley Sands: The Transmogrification of Historical Vertical Development to Horizontal Exploitation

2 Horizontal Exploitation of the Cotton Valley Sands in East Texas In the last 10 years, the Cotton Valley Sands of ETX/NoLa have been pursued within the industry horizontally, both in the Taylor Sands and also in the Upper Cotton Valley Sands. Since the Devon completion of the Lois Haygood #11 in Aug, 2006, operators have drilled just over 1000 Hzl wells in the CV in ETX/NoLa, not counting Terryville Field in No La. In the ETX/Sabine Uplift area, most of the attention has been in the Taylor Sand section, with varying targeted zones. In SE Panola Co and trending into Desoto/Caddo Ph s as well, the UCV has been targeted by many operators. These 2 areas will be the focus of the luncheon talk. As the Hzl CV Sand play continues to develop, geologists and engineers alike will be forced to work together to develop a mature understanding of OGIP, and then work through the reservoir characteristics of vertical completion/depletion variances as well as the calculation of un-drained potential within older vertical fields and their known limits. What has been understood as depleted may in fact not be well understood as we once thought? For the geologist, we can begin to understand xf and SRV, as well as BHP/Z. We all enjoy a well-behaved, un-drained reservoir; we just don t have as many of those around as we once did. And lest we get cocky, there s always working with the drilling engineers to get those drilling costs down and aid in becoming efficient. As geologists, we stand alone to assist in determining the horizontal target [are you sure you understand Net Pay ], work with drilling to get cost efficient [you may to actually GO OUT on location], and then work as hard with the reservoir /completions engineering groups to ensure a wells proper reserves are being produced [yes, hang out with engineers and listen to them; they re not all bad, I ve discovered]. To succeed in our HZL world, we should all endeavor to push our understanding of this age old reservoir, the Cotton Valley Sands. They ain t what they used to be!

3 We ve got a pretty good statistical database of vertical wells deeper than 9500 in ETX

4 By 2000, computers had been invented! Now cross-section making geologists had a cool tool to convince others that stratigraphy was a real thing, statistics matter, and the creative mind is a terrible thing to waste.

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6 Cotton Valley Formation Stratigraphy TYPE LOG Top of Cotton Valley CV A Sand CV B Sand 200 ft CV C Sand 350 ft Upper Taylor Sand 300 ft Lower Taylor Sand Top of Bossier Shale

7 Major CV Sand Horizontal Trends

8 Reserve Evaluation Methodology Systematic methodology using vertical performance and petro-physics for developing high graded locations. All identified locations have a unique single well analysis tied to geologic parameters and lateral length. Depletion model backs out calculated drainage area assuming 100% Taylor contribution. 2,000 1,850 1,000 Wells identified as economic at base case model were identified as PROB; all other locations identified as POSS. Single Well Parameters Well Spacing: 1000 Xf P initial: 10.8 ppg MW P final: 1500 psi BHT: 1.9 F/ F RF: 70% to 72% Porosity: Water Sat: Net Pay: ELL: Oil Yield: Water Yield: AVG across ELL AVG across ELL AVG across ELL VS - 660' - Drainage Based on Vertical Offset Based on Vertical Offset 8

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10 ESTIMATED STIMULATED INTERVAL N SRV: Stimulated Rock Volume S Upper Taylor Hzl Target Lower Taylor Taylor Base/Bossier Shale 10

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12 SCOTT JO ANN # T1 Clean SS Calcareous SS Shaly SS Shale Skeletal Grainstone T2

13 TW George offshore Lagoon Offshore Transition zone L. Shoreface Marginal Flood Channel U. Shoreface

14 Scott Jo Ann #5 Facies Log Core Description VFn Sandstone with Calcite Cement VFn Qz Sandstone. No Fiss Heavily Bioturbated Siltstone with abundant of Small Size Fossil Fragments Silty Shale

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16 UCV Stratigraphy A Sand B Sand C Sand Well #1H & 2H CNVL -C1- Sand Target

17 Approximately. 550 A A (2)(4) (1) and 5H target Most distal C-2 deposits

18 Target???

19 A Sand A A Cross Seciton Top B1 Sand Top B2 Sand Top B3 Sand Top C1 Sand Top C2 Sand Base C2 Sand New wells #1H & #2H A A

20 96 mo Cum: 3.6 bcfe Well 12-H

21 Well #2-H IP30: 7800 mcfe/d 34 mo Cum: 3.6 bcfe Well #1-H IP30: 8300 mcfe/d 34 mo Cum: 3.7 bcfe