Mechanistic investigation of the formation damaging characteristics of mixed metal hydroxide drill-in fluids and comparison with polymer-base fluids
- and others
Mixed metal hydroxide (MMH) fluids are highly thixotropic and have shown exceptional abilities in the areas of hole cleaning, suspension, and maintenance of good hole gauge even through very poorly consolidated sandstones. When a drill-in fluid based on an MMH has been used in reservoir sections, the ease of cleanup and the production rates have both exceeded expectations. Results have been better than those achieved on offsets where more conventional fluids have been used. Laboratory results have also shown properly formulated MMH fluids to have a low potential for formation damage. The primary objectives of the laboratory project presented in this paper were to (1) investigate the mechanisms by which filter cakes develop against sandstone faces, (2) study the natures of the cakes produced with different types of drill-in fluids, and (3) investigate the implications for cake cleanup. In a group of unweighted fluids an MMH fluid was found to be unique in its ability to form a predominantly external cake. It was further shown that the strong interactions between the MMH crystals and the bentonite platelets, which interactions provide the characteristic high shear thinning and almost instantaneous gelling behavior of such fluids, also contribute to the avoidance of damaging internal cake formation. This study demonstrates by dynamic fluid-loss measurements, imaging of dried filter cakes using an SEM, and direct imaging of wet filter cakes using an environmental SEM that the fluid is able to form mineral bridges over pore throats in a wide range of reservoir rocks. The external cake formed by the MMH fluid is easily removed by wash fluids or simply by application of backpressure as occurs when a well is brought on to production.
- OSTI ID:
- 166622
- Report Number(s):
- CONF-951002-; TRN: 96:000707-0046
- Resource Relation:
- Conference: Annual meeting of the Society of Petroleum Engineers (SPE), Dallas, TX (United States), 22-25 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of Drilling and completion. 1995 SPE annual technical conference and exhibition; PB: 882 p.
- Country of Publication:
- United States
- Language:
- English
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