The Wafra Ratawi is an example of a detached rimmed shelf carbonate shoal depositional system deposited on a paleo-high in the Late Cretaceous. The Wafra field is located in the Partitioned Neutral Zone (PNZ) between Kuwait and Saudi Arabia and has been producing medium oil from the Ratawi Oolite Limestone reservoir since 1956. (1) Kuwait Gulf Oil Company, Ahmadi - Kuwait, Kuwait. El-Gendi 1 John Weston 1 Bader Al-Otaibi 1 In Cherokee field, the most productive wells are located in the thickest part of the mound facies of the upper Ismay zone, where microporosity is well developed.Innovative Geoscience Solutions вЂ“ Meeting Hydrocarbon Demand in Changing TimesДeposition of Retrogradational Carbonate Grainstone Shoals and Subsequent Basal Barrier (Sole Seal) Development by Deposition and Diagenesis - Lower Cretaceous Ratawi Oolite Reservoir (Minagish Formation) Wafra Field, PNZ-Kuwait Production ''sweet spots'' and potential horizontal drilling candidates were identified for Cherokee and Bug fields. The work included (1) analysis of well-test data and oil production from Cherokee and Bug fields, San Juan County, Utah, and (2) diagenetic evaluation of stable isotopes from the upper Ismay and lower Desert Creek zones of the Paradox Formation in the Blanding sub-basin, Utah. This report covers research activities for the first half of the fourth project year (April 6 through October 5, 2003). The results of these studies can be applied to similar fields elsewhere in the Paradox Basin and the Rocky Mountain region, the Michigan and Illinois Basins, and the Midcontinent region. This study utilizes representative cores, geophysical logs, and thin sections to characterize and grade each field's potential for drilling horizontal laterals from existing development wells. Geological characterization on a local scale is focused on reservoir heterogeneity, quality, and lateral continuity, as well as possible reservoir compartmentalization, within these fields. Several fields in southeastern Utah and southwestern Colorado are being evaluated as candidates for moreВ В» horizontal drilling and enhanced oil recovery from existing vertical wells based upon geological characterization and reservoir modeling case studies. = ) of oil will not be recovered from these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs. That, together with the distribution of oil-filled inclusions, indicate the primary areas of the basin where migration and accumulation of oil occurred. Reconstruction of basin moreВ В» structure and maturation modeling show that cementation-oil migration was in the Cretaceous. Oil-filled fluid inclusions also occur in the spar, indicating oil was in a mobile phase at the time of cementation. The amount of uplift varies depending on basin location. The deep burial origin of the spar is based on fluid inclusion data, which also indicate that uplift followed the precipitation of spar. Following mixing zone diagenesis, further subsidence resulted in deep burial diagenesis, principally the occlusion of porosity by coarse calcite spar. 1 location, studies of the same types of data show a similar early diagenetic history. Cement, isotopic, and trace element stratigraphies of that interval indicate that primary porosity is preserved through early mineralogical stabilization of limestones in the mixing zone between freshwater and marine phreatic environments. 1 production interval, the porosity is mainly primary. Hence, the principal control on porosity is a diagenetic history. Throughout the basin, similar lithologies in the Great Oolite have porosities ranging from less than 5% to greater than 20%. The Middle Jurassic Great Oolite Limestone of the Wealden basin, southern England, is a target of active exploration owing to recent discoveries of oil, such as the Conoco No.

Oolite subjected to diagenesis