Determination Of Fissure Volume And Block Size In Fractured Reservoirs By Type-Curve Analysis Dominique Bourdet; Dominique Bourdet FLOPETROL Search for other works by this author on: This Site Google Scholar Alain C. Gringarten Alain C. Gringarten FLOPETROL Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, September 1980. Paper Number: SPE-9293-MS https://doi.org/10.2118/9293-MS Published: September 21 1980 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Bourdet, Dominique, and Alain C. Gringarten. "Determination Of Fissure Volume And Block Size In Fractured Reservoirs By Type-Curve Analysis." Paper presented at the SPE Annual Technical Conference and Exhibition, Dallas, Texas, September 1980. doi: https://doi.org/10.2118/9293-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 ABSTRACTA new type-curve is presented for analyzing wells with wellbore storage and skin in double porosity systems. This type-curve applies to damaged, acidized, and fractured wells in fissured reservoirs. In addition to the usual well and reservoir parameters (permeability, skin, wellbore storage constant and length of the fracture intersecting the well), analysis yields characteristic parameters that can provide quantitative information on the volume of fissures and the size of porous blocks in the reservoir. These, in classical methods, could only be obtained if semi-log radial flow were present at both early and late times, (thus yielding two characteristic parallel semi-log straight lines on a Horner plot), a condition that is seldom satisfied in practice.The analysis method presented in the paper is illustrated with actual field examples from several different fissured reservoirs.INTRODUCTIONThe large number of papers1–16 published in the last twenty years on the behavior of naturally fractured reservoirs reflects the importance to the oil industry of this type of producing formation. Although several, apparently different, theoretical models have been proposed, most practical methods for interpretation of transient tests are based on the existence of two parallel, semi-log straight lines, that is considered a characteristic feature of fissured reservoirs.Unfortunately, in most actual tests, the first semi-log straight line is usually obscured, and these methods cannot be used. As a result, only parameters characterizing the homogeneous behavior of the total system can be obtained (when conventional analysis methods are applicable), and those specific to the fracturation are usually not accessible.In this paper, we present new type-curves that can provide all the system parameters, by means of log-log analysis. These curves also permit to detect under which conditions the two parallel, semi-log straight lines are present, and can be used for interpretation. Utilization of the type-curves is illustrated on several actual field data, for which no satisfactory analysis was previously available.PREVIOUS WORKAvailable solutions for the behavior of fissured reservoirs are discussed in detail in Ref.16. A distinction is made there between models based on a detailed physical description of the fissured system, only suitable in relatively small scale, geotechnical type projects; and models where porous blocks and fissures are assumed uniformly distributed throughout the formation which is then treated as an â??equivalentâ?¿ system, either homogeneous or heterogeneous, as dictated by the general behavior of the actual test data. By â??equivalentâ?¿, it is meant a system whose calculated behavior is similar to the observed behavior of the real system.In this paper, we have only considered the case of reservoirs whose behavior cannot be matched with homogeneous models, and thus indicates the need to take heterogeneities into account. Among the various heterogeneous models suggested in the literature, the double porosity model is certainly the one that has attracted the most attention in the past. Until recently, however, published solutions were restricted to a â??basicâ?¿ model, (a line source or finite radius well, in a horizontal, constant thickness, reservoir of infinite lateral extent, with impermeable upper and lower boundaries), without any of the inner boundary conditions found in practice (wellbore storage, skin, fractures, etc . . .), although outer boundary conditions have been considered by some authors. As a result, these solutions were only applicable to the analysis of interference tests, or to that of data after the start of the infinite acting period in production tests. Keywords: Drillstem Testing, transition period, drawdown type-curve, determination, straight line, semi-log straight line, log-log analysis, buildup data, fissure, Upstream Oil & Gas Subjects: Formation Evaluation & Management, Drillstem/well testing This content is only available via PDF. 1980. Society of Petroleum Engineers You can access this article if you purchase or spend a download.