TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractOften, the main challenge in producing hydrocarbons in north Mexico is the accompanying large associated water production. In the Cuenca de Burgos field in northern Mexico, operators typically encounter water production of over 400 BWPD following fracture-stimulation treatments. This paper discusses how water production in those fields was significantly reduced using a new conformance-whilefracturing (CWF) method that incorporates a chemical relative permeability modifier (RPM) prepad.The formations were reported to have high watersaturation levels. Fracture-stimulation treatments performed in similar intervals usually (1) intersected a stringer of water within the targeted interval, or (2) extended into the highly saturated areas above and/or below the interval. Water cuts as high as 50 to 60% had made production of such intervals uneconomical.Data gathered from the first six months of production on more than seven wells in northern Mexico illustrate the economic benefit of the stimulation treatments using the new CWF technique. In many cases, the treatment has limited water production to less than 20%, and some applications have reduced water production to negligible levels. This paper discusses the job design, field application, and results of several CWF treatments performed in this area between 2004 and 2005.

In the Vaca Muerta shale of the Neuquén basin, Argentina, the most prolific intervals tend to be the most difficult to hydraulically fracture because of the abnormally high fracture gradients present in some parts of the basin. Thus, it becomes very important to have a good understanding of the anisotropic geomechanical properties of this heterogeneous formation prior to developing the completion strategy. A calibrated, anisotropic 1D mechanical earth model (1D MEM) was developed and used to optimize the completion strategy for a vertical well in the Vaca Muerta shale. The output from the 1D MEM, including the principal stresses, anisotropic elastic properties, pore pressure, and rock strength, were used to define the reservoir intervals with the best characteristics for initiation, propagation, and maintenance of a conductive complex fracture network. Next, the reservoir intervals with the highest hydrocarbon generation tendency were determined from petrophysical and image logs acquired in the well. This formed the basis for selecting the optimum number of stages and perforation strategy for the well. Sensitivity analysis revealed the impact of the hydraulic fracture properties on the production performance. The analysis showed that higher fracture conductivity greatly improves the well performance in the deeper Vaca Muerta intervals, whereas larger fracture surface area is more beneficial across the shallower intervals. Thus, a unique completion strategy was developed for each interval to optimize the well performance. Three hydraulic fracture stages were planned initially, but because of casing limitation, only the first stage was executed. A time-lapse acoustic measurement acquired from the well corroborated the propped fracture height predicted during the completion design phase. The study showed that proper characterization of the anisotropic geomechanical behavior of the Vaca Muerta formation improves the development of a completion strategy, which ultimately optimizes economic performance of the well.

No abstract

No abstract