Determination of Petrophysical Parameters Using Wireline Logs in Low Salinity Reservoirs (1995)

Determination of Petrophysical Parameters Using Wireline Logs in Low Salinity Reservoirs Peter A. Goode; Peter A. Goode SANTOS Ltd. Search for other works by this author on: This Site Google Scholar Andrew P. Pietsch; Andrew P. Pietsch SANTOS Ltd. Search for other works by this author on: This Site Google Scholar Neil V. Williams; Neil V. Williams SANTOS Ltd. Search for other works by this author on: This Site Google Scholar Alan M. Sibbit Alan M. Sibbit Schlumberger Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Asia Pacific Oil and Gas Conference, Kuala Lumpur, Malaysia, March 1995. Paper Number: SPE-29272-MS https://doi.org/10.2118/29272-MS Published: March 20 1995 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Goode, Peter A., Pietsch, Andrew P., Williams, Neil V., and Alan M. Sibbit. "Determination of Petrophysical Parameters Using Wireline Logs in Low Salinity Reservoirs." Paper presented at the SPE Asia Pacific Oil and Gas Conference, Kuala Lumpur, Malaysia, March 1995. doi: https://doi.org/10.2118/29272-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Asia Pacific Oil and Gas Conference and Exhibition Search Advanced Search AbstractThis study defines an approach to determine porosity, fluid saturations and permeabilities from wireline log data in sandstone reservoirs containing low salinity formation brines. An extensive set of measurements were made on low invasion core were analyzed to establish the ground truth, and to control the input parameter choices for log analysis.A recently developed water saturation equation, that accounts for the different geometry of the conducting paths along grain surfaces and within the pore fluid, was used to analyze the wireline resistivity logs. This equation predicts far less resistivity contrast between hydrocarbon and water-bearing intervals than other widely used relationships.The log interpretation technique consists of making robust estimates of highly sensitive parameters such as the cation exchange molarity, QV, and paying attention to the details in the estimation of the true formation resistivity, Rt and the formation resistivity factor, F.IntroductionThe determination of hydrocarbon saturation from resistivity logs in low salinity sandstone reservoirs is one of a class of problems referred to in the literature as "low (resistivity) contrast pays". Interpretation difficulties arise principally because the conductivity of the grains (related to shaliness) is as important as the conductivity of the formation water, and the conditions for the Archie formulae to relate resistivity solely to water saturation no longer apply. The problem is compounded by the difficulty of precisely estimating the shaliness from well log data. Slight changes in the estimates of shaliness can result in large changes in the derived values of saturation.There are numerous shaly-sand saturation equations in the literature: these can be loosely divided into two types of models: the Vsh (shale volume) models, and; the double layer (surface conductance) models. Hill and Milburn were amongst the first to relate the CEC (cation exchange capacity) to the effective shaliness. Waxman, Smits and coworkers developed this idea into a model (the "WS" model) which has gained widespread acceptance in the industry. The WS model relates the additional conductivity of shaly sands to the cation exchange molarity (or cation exchange capacity per unit pore-volume), QV. In water-filled rocks at high salinities this additional conductivity is proportional to QV:(1) Keywords: saturation, core analysis, porosity, log analysis, determination, filtrate, kaolinite, reservoir, water saturation, salinity Subjects: Formation Evaluation & Management, Open hole/cased hole log analysis This content is only available via PDF. 1995. Society of Petroleum Engineers You can access this article if you purchase or spend a download.