Tight formations are being developed by drilling in the Midland Basin. Target intervals include Clearfork, Wolfcamp, Spraberry, Strawn, Cline, Atoka, and Mississipian formations, which are usually found between 6000 feet and 11,500 feet true vertical depth (TVD). Development is typically with vertical wells, which are stimulated with multiple hydraulic fractures targeting the expected pay intervals and are produced commingled. A significant challenge for operators is determining the optimum well locations and spacing for efficient reserve development. Operators use various field data and analytics to determine well spacing, although limited data pose challenges to making the best decisions. Numerical models can yield insights about drainage patterns and potential interference. This paper reports a case study using a geologic model, hydraulic stimulation models, and a reservoir simulation model to evaluate reduced well spacing impacts on recovered oil and economics. A three-dimensional geologic model was constructed for a 14-section area in the Midland Basin. An extensive core-log statistical study yielded calibrated rock types at the wells. Reservoir and geomechanical properties were then spatially distributed using geostatistical techniques subject to data constraints. A reservoir simulation model was then utilized on a sector area of the full model. The sector model was history-matched to early production data and historical type curves. Each well had 10–12 fracture stages, which were explicitly modeled using parameters derived from post-execution analysis of fracture job data. The paper presents history-matched simulation models that were executed to predict production and economics for 40-acre and 20-acre well spacing cases.

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Photooxidation of chlorophenols was studied and the results were analyzed. It has been found that 4-chlorophenol is oxidized faster than other chlorinated phenols, indicating that higher chlorinated phenols are hard to decompose and the order of the decomposition was as follows: 4-CP > 2,4-DCP > 2,4,6-TCP > PCP.

An association of benthonic foraminifera, Late Oligocene to Early Miocene in age, characteristic of the Monagas area, Eastern Venezuelan Basin, is presented in this paper.The identified assemblage could indicate a sequence boundary between a lowstand wedge and a transgressive system tract; this assemblage overlies the Naricual Formation oil sand reservoirs; therefore it is very important to have it well described.The studied assemblage has been picked out of samples analyzed from ten wells in the El Carito - El Furrial area. A total of one hundred species were identified, including twenty species turned out to be unidentifiable. Four new taxa have been described in this age interval.The fauna exhibits strong dominance, being the main species: Nonionella opima, Nonion atlanticus, Textularia cf. T. grenadana, Textularia sp., Textularia panamensis, Valvulineria sp., Ammonia beccarii, Nonionella sp., and Trochammina sp. All these species correspond to a transitional to inner neritic environment.The detailed identification of this fauna assemblage will contribute to a better understanding of the stratigraphy in the area, and in consequence to optimize hydrocarbon exploration.

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