Gas Well Deliquification Workshop Adams Mark Hotel, Denver, Colorado March 5 - 7, 2007 Foam Flow and Foam Assisted Lift Danny Lillard, Technical Representative Champion Technologies , Joe Lopez, Artificial Lift / Corrosion Rep. South Texas Operating Area, Chevron Jose M Macias. Gas Treatment Technical Manager, Champion Technologies
Outline • Foam Flow vs Fluid Flow • Critical Rate Benchmark • Foam Effect at Various Points Below Critical Rate • Field Case Study Foam Effects At Various Points Below Critical Rate 2007 Gas Well Deliquification Workshop 2 Mar. 5 - 7, 2007 Denver, Colorado
Foam Flow vs Fluid Flow • Fluid Flow : Well defined flow regimes and transitional velocity data established. 2007 Gas Well Deliquification Workshop 3 Mar. 5 - 7, 2007 Denver, Colorado
Foam Flow vs Fluid Flow • Fluid Flow: 2007 Gas Well Deliquification Workshop 4 Mar. 5 - 7, 2007 Denver, Colorado
Foam Flow vs Fluid Flow • Foam Flow : – Laboratory data obtained from 20ft x 2.441 ID column. – Low Pressure (0-1.5 psig) flow rates up to 300Mscfd. • Foam Flow Regimes: – Column flow, slug flow and annular flow – Transitions occur at different points along the flow regime map boundaries. 2007 Gas Well Deliquification Workshop 5 Mar. 5 - 7, 2007 Denver, Colorado
Foam Flow vs Fluid Flow • Foam Flow is predominantly slug flow with variance in slug frequency and slug size. – As gas velocity increases slug frequency increases. – As gas velocity increases slug size decreases. 2007 Gas Well Deliquification Workshop 6 Mar. 5 - 7, 2007 Denver, Colorado
Foam Flow vs Fluid Flow 2007 Gas Well Deliquification Workshop 7 Mar. 5 - 7, 2007 Denver, Colorado
Critical Rate Benchmark • The use of the critical rate for a benchmark along the flow regime maps has been used in the laboratory to describe fluid flow and foam flow behavior. – Fluid Flow: As flow falls below critical then • 1. Wispy Annular is observed • 2. Churn flow is observed • 3. Slug flow is observed • 4. Bubble flow is observed 2007 Gas Well Deliquification Workshop 8 Mar. 5 - 7, 2007 Denver, Colorado
Critical Rate Benchmark • The use of the critical rate for a benchmark along the flow regime maps has been used in the laboratory to describe fluid flow and foam flow behavior. – Foam Flow: As flow falls below critical then • 1. Annular flow is observed • 2. Slug flow (with varying slug size and frequency) is observed • 3. Column Flow is observed – Foam flow shows the ability to generate vertical moving slugs 75% below the critical rate in laboratory testing thus it is expected to find some wells flowing at 75% below the critical rate in the field. 2007 Gas Well Deliquification Workshop 9 Mar. 5 - 7, 2007 Denver, Colorado
Critical Rate Benchmark • Candidate wells may fall into several categories benchmarked by critical rates. • Wells significantly below critical rate are likely in (Fluid Flow) slug or bubble flow and therefore more liquids are being retained in the well bore. • An intermediate range below critical rate are wells in churn and possible wispy annular flow • Wells close to critical rate are wells in wispy annular flow. * This indicates that several flow regimes can be happening through out the length of the tubing. 2007 Gas Well Deliquification Workshop 10 Mar. 5 - 7, 2007 Denver, Colorado
Foam Flow Below Critical Rates – Foam flow does not change the transition velocities from one flow regime to another in liquid flow. – Foam flow generates a new flow regime map. – Foam flow allows for upward movement of fluids in a foamed state were fluids would be retained in the vertical tube in an un-foamed state. 2007 Gas Well Deliquification Workshop 11 Mar. 5 - 7, 2007 Denver, Colorado
Field Case Study • Chevron South Texas Operating Areas Case Study – 30 Wells Analyzed – Modeled for flow (Critical Rate Benchmark) – Compared incremental gas from Benchmark The delivery method of foam application for these wells is continuous capillary injection. 2007 Gas Well Deliquification Workshop 12 Mar. 5 - 7, 2007 Denver, Colorado
% Below Critical Rate of Various Foam Assisted Wells 92.76 80.73 77.02 73.26 71.24 64.30 62.08 56.10 49.07 48.64 44.84 44.08 38.10 31.21 29.49 26.09 23.58 19.38 14.95 10.30 8.41 -2.32 -3.18 -6.66 -20.00 0.00 20.00 40.00 60.00 80.00 100.00 2007 Gas Well Deliquification Workshop 13 Mar. 5 - 7, 2007 Denver, Colorado
Increm ental Gas Vs Critical Rate 600.00 % Below Critical Rate % Incremental Gas 500.00 400.00 300.00 200.00 100.00 0.00 -100.00 2007 Gas Well Deliquification Workshop 14 Mar. 5 - 7, 2007 Denver, Colorado
Critical Rate Comparison On Foam Assisted Lift Applications • Wells are being foam assisted from 10% above the critical rate to 80% below the critical rate. • The incremental gas varies from well to well. • No trend data has yet been observed based on the incremental gas and % below critical rate. 2007 Gas Well Deliquification Workshop 15 Mar. 5 - 7, 2007 Denver, Colorado
Critical Rate Comparison On Foam Assisted Lift Applications • Specific Examples: – R Vidaurri# 20 • Before foam assisted lift producing at 80.65% below the critical rate after foam assisted lift producing at 64.30% below critical rate. – R Vidaurri# 29 • Before foam assisted lift producing at 88.00% below the critical rate after foam assisted lift producing at 71.24% below critical rate. 2007 Gas Well Deliquification Workshop 16 Mar. 5 - 7, 2007 Denver, Colorado
Critical Rate Comparison On Foam Assisted Lift Applications – Wells producing significantly below critical rate show benefit from foam. – Testing is underway to look at wells at or slightly above the critical rate for overall benefit from foam. 2007 Gas Well Deliquification Workshop 17 Mar. 5 - 7, 2007 Denver, Colorado
Conclusions: • Foam assisted lift has been used successfully at up to 80% below the critical rate. • Foam Flow is dependent on flow regime transition boundaries and has independent flow patterns. • Main flow pattern is slug flow with varying frequency and slug size. 2007 Gas Well Deliquification Workshop 18 Mar. 5 - 7, 2007 Denver, Colorado
Disclaimer The following disclaimer may be included as the last page of a Technical Presentation or Continuing Education Course. A similar disclaimer is included on the front page of the Gas Well Deliquification Web Site. The Gas Well Deliquification Steering Committee Members, the Supporting Organizations and their companies, the author(s) of this Technical Presentation or Continuing Education Course, and their company(ies), provide this presentation and/or training at the Gas Well Deliquification Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained. 2007 Gas Well Deliquification Workshop 19 Mar. 5 - 7, 2007 Denver, Colorado
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