Adopting Aphron Fluid Technology for Completion and Workover Applications

Abstract

The literature describes several applications where Aphron fluid technology has been applied in both drilling and re-entry scenarios and includes an extensive description of how this fluid system works. A highly efficient leak-off prevention mechanism makes aphron based fluid systems beneficial for certain completion and workover applications as well, where formation damage could be avoided by the practical elimination of fluid-fluid or fluid-rock interaction or where simply the workover objectives can be achieved by obtaining efficient circulation of fluid to surface. Completion and workover applications for this fluid system have not been extensively reported. This paper reviews three applications of Aphron fluid technology in different completion and workover scenarios. The selected cases were reviewed to present some of the technical and operational lessons learned and to some extent discuss the observed formation cleanup behavior. The following three applications were reviewed: completion of a dual string sour gas well, using an oil based aphron system for kill fluid, with practically no kill fluid loss to a hydraulically fractured formation; the completion of additional zones within a depleted dolomitic limestone formation on two wells where the method of Aphron fluid placement was found to significantly affect fluid losses; and finally, the enabling of the provision of annular pressure support at pressures which approached the hydraulic fracture opening pressure of a shallow zone while hydraulically fracturing a deeper zone through tubing with a packer. Introduction The mechanisms by which the Aphron fluid system operates make it a reliable tool for certain completion and workover applications. These mechanisms have been described extensively in the literature (Brookey 1998; Ivan et al 2001; Growcock et al. 2005a; Catalin et al. 2002; Hoff, O'Connor and Growcock 2005). Moreover, the presentation of field performance data for Aphron fluids in drilling and re-entry operations is also extensively published (Ivan et al. 2001; White et al. 2003; Brookey et al. 2003; Rea et al. 2003 and Kinchen et al. 2001). Lessons learned from the performance of Aphron fluids in a wide range of applications have caused a specific profile to evolve for the effective use of this fluid technology. Brookey (1998) showed that the high low shear rate viscosity (HLSRV) of the Aphron fluid system, which provides the proper environment for aphron bubble formation and survival, also provides a high resistance to flow under low shear conditions, which significantly inhibits initial fluid loss to the formation. Brookey (1998), supported by Ramirez et al. (2002) showed that the creation of aphron aggregates is an effective filtrate control mechanism which further reduces fluid loss. Formation damage prevention is attributed to the inert gas which makes up the majority of an aphron aggregate, combined with the limited amount of fluid invasion into a potential leakoff zone. Adverse fluid-fluid and fluid-rock reactions are prevented because the completion and workover fluid is not available as a reactant or contaminant.

The Past, Present and Future of Aphron Based Drilling Fluids

“…It was Tom Brookey who first introduced aphron into petroleum industry for horizontal well drilling in 1998 [3] . After that successful field application, aphron had been widely used to redevelop the low pressure H 2 S gas carbonate formation in the Indian Basin Field of New Mexico, USA, in 2001 [4] , to control lost circulation while drilling highly fractured formation in California, USA, in 2001 [5] , to drill depleted reservoirs in Lake Maracaibo in 2002 [6,7,8] , to drill depleted formations in the North Sea 2003 [9] , to use as workover fluid in depleted mature fields in Tajin area of the Poza Rica in the Eastern Mexico 2003 [10] , to drill fractured granite formation in Yemen 2005 [11] and to complete and workover well in the cretaceous conglomerate sands of the deep basin region in Alberta, Canada, in 2008 [12] . Application results turn out that aphron based drilling fluid can be used to drill low-pressure reservoirs where UBD was unsuccessful.…”

Environmental and strength‐enhanced nanosilica‐based composite gel for well temporary plugging in high‐temperature reservoirs

“…However, it needs to be prepared under high‐speed agitation at about 10,000 r/min, which may be not easy to be achieved under the field condition. MacPhail et al researched on the application of aphron fluid and found that it can significantly prevent wellbore fluid loss and enable the well operation to be executed under dead well. Yet the foam is mainly used for the ultra‐low pressure oil and gas field.…”

Experimental study of rheological properties of aphron based drilling Fluids and their effects on formation damage

“…In the fourth and last applications, in a sisquoc sand well (unconsolidated permeable sand) aphron HYSST, drilling uid provided invasion control and avoided instability that might be encountered in sand wells. MacPhail et al [46] described several case studies of wells in Alberta and Mississippi. Aphron uid technology was successfully applied in several completion and workover applications leading to reduced uid loss.…”