The Succesful Evolution of Anton Irish Conformance Efforts

Abstract

The Succesful Evolution of Anton Irish Conformance Efforts David D. Smith; David D. Smith Occidental Permian Ltd. Search for other works by this author on: This Site Google Scholar Mark Joseph Giraud; Mark Joseph Giraud Oxy USA Inc. Search for other works by this author on: This Site Google Scholar Craig Kemp; Craig Kemp Occidental Permian Ltd. Search for other works by this author on: This Site Google Scholar Melinda Swepston McBee; Melinda Swepston McBee Occidental Permian Ltd. Search for other works by this author on: This Site Google Scholar Jesse Taitano; Jesse Taitano Occidental Permian Ltd. Search for other works by this author on: This Site Google Scholar Michael Winfield; Michael Winfield Occidental Permian Ltd. Search for other works by this author on: This Site Google Scholar J.T. Portwood; J.T. Portwood TIORCO, Inc. Search for other works by this author on: This Site Google Scholar Don M. Everett Don M. Everett Halliburton Energy Services Group Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, September 2006. Paper Number: SPE-103044-MS https://doi.org/10.2118/103044-MS Published: September 24 2006 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Smith, David D., Giraud, Mark Joseph, Kemp, Craig, McBee, Melinda Swepston, Taitano, Jesse, Winfield, Michael, Portwood, J.T., and Don M. Everett. "The Succesful Evolution of Anton Irish Conformance Efforts." Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, USA, September 2006. doi: https://doi.org/10.2118/103044-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search AbstractThe Anton Irish field was discovered in 1945, unitized in 1950 for a produced gas pressure maintenance project and converted to a waterflood in 1969. In 1997 CO2 flooding began and currently accounts for about 85% of the unit production. Presently, the entire field produces around 6,500 BOPD; 36.5 MMCFPD of recycled CO2, and 69,200 BWPD. Over the years of flooding, various conformance problems have been identified and many attempts have been made to address these problems with limited to no success. In 2003 a new program was initiated to re-evaluate the problems and design better solutions. This paper will outline the diagnostic efforts that were undertaken, discuss the basic findings of that effort, review the resulting solutions that were designed to resolve these problems, and show the results of this work.Basic Problem / JustificationFor manyyears the rapid breakthrough of the displacing fluid whether it was water or CO2 has been recognized as a severe problem in the Anton Irish Field. This rapid breakthrough and excess cycling of CO2 in the Anton Irish Clearfork flood has led to numerous wells being shut in due to limited processing capacity at the gas plant. In addition wells that had previously produced at relatively high oil rates became uncompetitive due to this excess gas production. Thus, in order to recover reserves from these areas, a solution needed to be found to address these excess cycling problems.A key complicating factor to deal with at Anton, is that almost all wells have open hole completions. This creates additional diagnostic problems as it is difficult to get to bottom with wireline on most injectors which prevents good injection profile data.Conformance Project Progression:Early in 2003 plans were developed to expand on past experiences, identify key knowledge gaps, and refocus efforts that would lead to a better understanding of the conformance problems. This effort included: identifying key assumptions and understandings; researching historical data; determining additional data needs; running diagnostics; and evaluating this data in order to modify and improve our problem model. In this process we included the ability to learn from any solutions designed and executed, so that reformulated solutions would be more effective as our problem knowledge increased.Early Conformance Efforts:Prior to 2003 the Anton conformance problems were perceived to be limited to relatively low volume near wellbore features or controlled by high permeability streaks. Efforts to control these features lead to the solution designs outlined in Table 1. Three things characterized this effort, first, all the treatments were relatively small in volume, second, all the solutions were perceived as near wellbore solutions, and third they were all unsuccessful in improving the control over the Anton Irish conformance issues. Reviewing additional reservoir monitoring data including, production and injection pattern rate analysis, interwell tracers, re-evaluation of core samples, ultrasonic image logs, Hall plot analysis, step rate tests, and downhole camera inspections, led to a new perception of the problem. Examples of this data are included in Figures 1 thru 6.As we continued to improve our understanding of the problem, all data pointed to large void space features, originally generated as induced fractures and enhanced over time by rock dissolution and/or erosion caused by the flooding process. Step rate tests which showed bottom hole pressure increases of < 20 psi for a 4,500 BWPD rate increase, and fast connections to wells ∼1,200' away allowed us to calculate an equivalent of approximately 4.5″ pipeline flow. Camera inspections also showed > 3″ wide openings on the injectors and ½″ wide openings on the producers, even though we were only able to effectively inspect small portions of the wellbores. Careful inspection of all this information led us to conclude that we have created massive void space flow conduits with relatively direct communication between many injectors and specific producers. Obtaining this diagnostic data, and the resulting drastic change that this made to our problem model, was critical to identifying and characterizing the root cause and allowing us to design a new and unique solution to control the inter-well communication for this field. Keywords: enhanced recovery, flow in porous media, breakthrough, conformance improvement, Fluid Dynamics, log analysis, waterflooding, injector, well logging, injection pressure Subjects: Reservoir Fluid Dynamics, Improved and Enhanced Recovery, Formation Evaluation & Management, Flow in porous media, Waterflooding, Conformance improvement, Open hole/cased hole log analysis This content is only available via PDF. 2006. Society of Petroleum Engineers You can access this article if you purchase or spend a download.