Gas Production From Low Permeability Carbonates Enhanced Through Usage of New Acid Polymer System
Bibliographic record
Abstract
Gas Production From Low Permeability Carbonates Enhanced Through Usage of New Acid Polymer System Steve Metcalf; Steve Metcalf BJ Services Company, Search for other works by this author on: This Site Google Scholar Henry Lopez; Henry Lopez BJ Services Company, Search for other works by this author on: This Site Google Scholar Charlie Hoff; Charlie Hoff Pioneer Natural Resources USA, Inc. Search for other works by this author on: This Site Google Scholar George Woo George Woo GF Services Search for other works by this author on: This Site Google Scholar Paper presented at the SPE/CERI Gas Technology Symposium, Calgary, Alberta, Canada, April 2000. Paper Number: SPE-59756-MS https://doi.org/10.2118/59756-MS Published: April 03 2000 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Metcalf, Steve, Lopez, Henry, Hoff, Charlie, and George Woo. "Gas Production From Low Permeability Carbonates Enhanced Through Usage of New Acid Polymer System." Paper presented at the SPE/CERI Gas Technology Symposium, Calgary, Alberta, Canada, April 2000. doi: https://doi.org/10.2118/59756-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Unconventional Resources Conference / Gas Technology Symposium Search Advanced Search AbstractGas production from the Strawn Limestone formation in Crockett County, Texas is generally only commercial after stimulation. Historically, the most successful stimulation treatments typically consist of large acid fracturing treatments. Several techniques have been used, including gelled acid, gelled water pads and gelled acid pumped in alternating stages and crosslinked acid systems.Gelling of acids has been accomplished for years using emulsions to facilitate the addition of polymer to acid to achieve good hydration. Recently, a new emulsion system and polymer were introduced into this area which significantly improved efficiency both in developing fluid properties and operations on location. The micelles of this new polymer emulsion are approximately 1/15th the size of those previously applied. The polymer emulsion uses a highly specific external activator to initiate and promote hydration, dramatically reducing the formation of "fisheyes". In addition, it allows for continuous mix operations on location.Production results are presented from three wells, showing a 34% improvement in production in which the new polymer system has been used. In addition, production responses to several different treatments are compared, which show crosslinked acid fracture treatments to be the most successful. Treatment details along with a description of the new emulsion chemistry and operational advantages are presented.BackgroundCrockett County, Texas Strawn Limestone.The Strawn Limestone formation located in Crockett County, Texas is a naturally fractured low permeability "tight gas" reservoir1. Several types of treatments have been performed in the past in an attempt to maximize the production of the gas reservoir. This has proved difficult primarily due to the low permeability and natural fracturing of the formation1. These treatments have included conventional acidizing with HCl, acid fracturing with gelled HCl, gelled water pads and HCl, gelled or crosslinked pumped in multiple stages and prop fracture treatments, utilizing Zirconium crosslinked CMHPG commingled with CO2, and high pH borate crosslinked guars.Gellation of Hydrochloric Acid.The gellation of hydrochloric acid (HCl) for use in the oil industry began in the mid-1970's. There were many difficulties with adding polymers to acid. These included lumping or "fisheyes" due to incomplete hydration, safety in handling the addition of polymer powders to strong acid and time to realize final viscosity development of the polymer (possibly several hours).However, the benefits were numerous. Higher pumping rates were possible allowing for better acid fracturing of carbonates. The viscosity of the acid reduced the overall spending of the acid on the formation allowing for deeper penetration of etched width. Residual acid viscosity resulted in removal of formation materials, released by the acid but not dissolved, from the well. Less acid volume overall could be pumped to get the same stimulation results.Over the years, the industry has made changes in the polymers and the methods of incorporating them into acid systems. A big improvement was the use of emulsion polymers, in which the polymer was held in an emulsion until mixed with the acid and then an internal activator would invert the emulsion exposing the polymer to acid and allow hydration to occur. Emulsion polymers have been used in the industry for a variety of other applications, such as in drilling muds.Crockett County, Texas Strawn Limestone.The Strawn Limestone formation located in Crockett County, Texas is a naturally fractured low permeability "tight gas" reservoir1. Several types of treatments have been performed in the past in an attempt to maximize the production of the gas reservoir. This has proved difficult primarily due to the low permeability and natural fracturing of the formation1. These treatments have included conventional acidizing with HCl, acid fracturing with gelled HCl, gelled water pads and HCl, gelled or crosslinked pumped in multiple stages and prop fracture treatments, utilizing Zirconium crosslinked CMHPG commingled with CO2, and high pH borate crosslinked guars.Gellation of Hydrochloric Acid.The gellation of hydrochloric acid (HCl) for use in the oil industry began in the mid-1970's. There were many difficulties with adding polymers to acid. These included lumping or "fisheyes" due to incomplete hydration, safety in handling the addition of polymer powders to strong acid and time to realize final viscosity development of the polymer (possibly several hours).However, the benefits were numerous. Higher pumping rates were possible allowing for better acid fracturing of carbonates. The viscosity of the acid reduced the overall spending of the acid on the formation allowing for deeper penetration of etched width. Residual acid viscosity resulted in removal of formation materials, released by the acid but not dissolved, from the well. Less acid volume overall could be pumped to get the same stimulation results.Over the years, the industry has made changes in the polymers and the methods of incorporating them into acid systems. A big improvement was the use of emulsion polymers, in which the polymer was held in an emulsion until mixed with the acid and then an internal activator would invert the emulsion exposing the polymer to acid and allow hydration to occur. Emulsion polymers have been used in the industry for a variety of other applications, such as in drilling muds. Keywords: hydrochloric acid, flow in porous media, fracture, hydration, gas production, acid fracture treatment, acidizing, gelled water pad, fluid dynamics, guar gelled 2 Subjects: Hydraulic Fracturing, Reservoir Fluid Dynamics, Acidizing, Flow in porous media, Well Operations, Optimization and Stimulation This content is only available via PDF. 2000. Society of Petroleum Engineers You can access this article if you purchase or spend a download.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".