Petrophysics free essay sample

Conceptual The South Tapti gas field, situated in the Arabian Sea off the western shoreline of India, has been on creation throughout the previous three years. Drill Stem Tests (DST) directed in five zones in the principal evaluation very much indicated high sand creation in all the tests at drawdowns as low as 20 psi. Because of the unconsolidated idea of the store sand, it was chosen to rock pack every future well. At first, the High Rate Water Pack (HRWP) strategy was utilized on 13 fruitions including some stack and particular culminations. Because of an adjustment in the boring liquid to an oil based mud (OBM) framework and the higher harm related with the it, it was later chosen to switch the rock pressing procedure to ‘Frac and Pack’. This included formation of a little frac to sidestep the close wellbore harm utilizing a gel-based liquid, trailed by rock arrangement utilizing the HRWP. The Frac Pack strategy was taken a stab at 10 fruitions. Broad creation and weight information gathered on the above fulfillments show that the ‘Frac Pack’ procedure has prompted a diminishing in the mechanical skin by very nearly 70 %. All the more significantly, it has likewise been liable for diminishing the Rate Dependent Skin Coefficient, D, by 50 %, which greaterly affects the well profitability since these wells are created at normal paces of 25 MMSCFD. This paper depicts the rock pressing methods utilized in the South Tapti gas field, their advancement and the outcomes accomplished. Inroduction The South Tapti field, situated off the Western shoreline of India, is spoken to by a progression of exchanging sand and shale arrangements. The upper repository interims are ruled by tidal-bar and divert sands stored in a deltaic domain while the lower sands speak to etched valley stores comprising generally of alluvial/fluvial channels, tidal bars and tidal streams. The exploratory wells penetrated in the field showed solid sand creation inclinations because of the unconsolidated idea of the store rock. This was authenticated by broad testing of the primary improvement well when all the five zones tried delivered sand much under very low tension drawdown conditions. The consummation arrangement for the field concentrated on forestalling sand entrance while limiting the close to all around bore harm natural in any sand control application. The early advancement wells were rock stuffed utilizing the high rate water pack (HRWP) method. These underlying consummations were profoundly effective in forestalling sand creation yet additionally incited huge harm all the while. The issue was emphasizd when the boring mud framework was changed to an oil base framework trying to balance repetitive penetrating issues emerging out of unconsolidated sandstone and nearness of responsive dirts. This required an adjustment in consummation theory so as to guarantee that the wells hold high efficiency with successful sand control. Geologic and Reservoir Characterization The South Tapti field is restricted by a wide SW-NE drifting, doubly plunging anticline. The field has up to 13 distinctive Oligo-Miocene gas bearing sands, isolated by shales. The supply sands were stored in both etched valley and deltaic settings. Repository sands inside chiseled valleys comprise of alluvial/fluvial channels, tide-affected channels and tidal bars. The channel sands commonly are the cleaner sands with superb porosity penetrability and up to 20 m thick, though the tide-affected channels and tidal bars are shalier, with increasingly unassuming porosity and porousness. Dirt MINERALS 1. Dynamic: Tapti Basin in Surat Depression, Bombay Offshore is portrayed by totally siliciclastic progression. The centers and cutting examples, and wireline logs give significant data about the stratigraphy, bowl fill, mineralogy, source and store rock qualities. Well under investigation is situated in South Tapti sub-bowl and contains gas-bearing sandstone inside Mahim Formation of Late Oligocene age. The cuttings and centers have been megascopically analyzed and with the guide of electrical log information, the litholog of the well is readied. The examination includes XRD and significant component investigation of chose tests. The XRD and advanced log information from Natural Gamma Sepctrometry (NGS) log show that montmorillonite is the significant dirt mineral present in the upper piece of the progression, though kaolinite present in the lower section (1868 m MD to 2427 m MD). Kaolinite is obviously framed by beginning periods of internment diagenesis, while montmorillonite is an enduring result of the Deccan Basalt. Interpretative lithology from the well log reaction shows that store sandstones include created inside the profundity interim of 1865m TVD to 1945 m TVD inside predominantly shale lithology. Store sandstones are semiconsolidated, medium to coarse grained and decently all around arranged. Quartz is the predominant detrital part in all the sandstones. Pay sands are quartz arenite though non-pay sands are quartz wacke with fluctuating measure of dirt grid. Kaolinite in the store area decreases the penetrability of quartz wacke, however improving porosity in microlevel. Carbonate, siderite and iron oxide are primary solidifying material. Significant component information demonstrating that clastic residue were conveyed to the bowl conceivably by the Proto Tapti stream yet they might be having double wellspring of source. The discriminant elements of Meyer and Nederlof, 1984 has demonstrated that the considered arrangements don't have source rock potential. Watchwords: Tapti Basin, Bombay Offshore, hydrocarbons, provenance and earth minerals. quartz wacke, however improving porosity in microlevel. Carbonate, siderite and iron oxide are principle establishing material. Significant component information indicating that clastic silt were conveyed to the bowl conceivably by the Proto Tapti waterway yet they might be having double wellspring of beginning. The discriminant elements of Meyer and Nederlof, 1984 has shown that the considered arrangements don't have source rock potential.