The mechanical-properties log provides a quantitative means for identifyingsands that are strong enough to produce oil and gas without any form ofsand control. The method is based on a correlation of in-situ strengthwith the dynamic elastic moduli computed from sonic and density logs. Introduction To meet current demands for more oil and gas, companies would like to increase production. However, increases in well-production rates are frequentlyaccompanied by sanding problems. For this reason, there is often reluctance to go to higher producingrates.Yet many sands are, in fact, strong enough topermit greater production. It would be highly beneficialto be able to recognize these. It is also important toknow beforehand which sands are too weak to beproduced at the higher rates because once the wellhas made sand, consolidation is difficult and oftenineffective.Many factors must be considered to understandthe sanding problem. The pressure gradient near theperforation, the flow rate per foot, and the scrubbingaction of the fluid being produced all interact toimpose destructive forces on the sand. The ability ofthe sand to withstand these destructive forces isdetermined by two main factors: the intrinsic strengthof the formation, and the capability of the sand toform stable arches around the perforations.The intrinsic formation strength is governed bythe state of the confining stress (as determined bythe difference between the overburden stress and thepore pressure), the grain shape and sorting, and thecementation between the grains. Shaliness maycontribute to the cementation.There is a good correlation between theformations intrinsic strength and the ability of theformation to produce at a high flow rate. Moreover, the consistently lower permeabilities of the strong sandslimit the magnitudes of the flow rates to which theyare exposed. Conversely, weak sands have relativelyhigh permeabilities and are capable of producing athigh flow rates, even with small drawdowns. Forthese, sanding is a potential danger.Although we believe that a criterion based on theintrinsic strength is basic and fundamental, there areother factors that cannot be ignored. For instance, the type of fluid being produced is important. Ourexperience to date has been predominantly with gasand oil production, but it is believed that productionwith a high water cut may require higher intrinsicstrength.Resistance to sanding in a weakly cemented sandcan result from the formation of a stable, load-carryingsand arch spanning the producing cavity. In this respect, published work on laboratory experimentsindicates that the presence of two different fluids(e.g., oil and water) in the formation, with the wetting-phase saturation near irreducible, maycontribute cohesive forces between the sand grains.These forces help sustain a stable arch after some sanding has occurred. The forces result from theinterfacial tension between the two fluids where theirsurface contacts the sand grains, and the effect is topull the sand grains together. JPT P. 283^

Failure analysis application of analytical TEM analysis was handicapped in the past by the difficulty associated with specimen preparation of specific devices in complicated integrated circuit arrays. We have published several papers detailing methods for preparing TEM specimens with high specimen preparation spatial resolution in periods of about two to four hours. This paper offers a case history of a TEM failure analysis that combines high spatial resolution specimen preparation and the utilization of chemical junction delineation techniques.The device failure came to light in a chip tester prior to shipment. Tester electrical diagnostics identified a particular cell within a large array as defective. The fail's electrical signature further narrowed-down the potential candidates to a small number of devices within the cell. The chip was examined in transmission in an IR microscope. Anomalous IR contrast was observed in the emitter of one bipolar device in the suspect region (Fig. 1). A series of conventional light-optical photographs, with increasing magnification, were taken to define the failure location. Using the light-optical photos as a guide, the failed emitter was bracketed with laser craters. The specimen preparation polishing operation used the laser craters to achieve a plane-of-polish through the suspect emitter.

A new tool provides simultaneous recording of measurements from all downhole production-logging sensors used in the analysis of production or injection wells. The system was used to evaluate production-well profiles in the South Swan Hills miscible flood project in Alberta, Canada. The dynamic reservoir picture obtained from the information proved useful in improving reservoir performance. Introduction Production logs have been used for many years to Production logs have been used for many years to evaluate producing and injection wells. In the past, when reservoirs with excess capacity were limited by allowables, production logs were used basically to diagnose a problem on an individual well, such as locating a source of water production or defining a mechanical problem such as a packer leak. Today, with the increased demand for oil and the declining capacity of mature reservoirs, combined with more sophisticated recovery schemes, the oil industry is becoming increasingly aware of the importance of improving fieldwide reservoir performance. With this shift in emphasis, the role of production logging has taken on a much wider scope.For the evaluation and management of a reservoir, the reservoir engineer may get the information he needs by running production logs on selected production and injection wells throughout the production and injection wells throughout the reservoir. By repeating this on an appropriate time scale, a dynamic description of the reservoir can be evolved. This information can be integrated with formation evaluation logs, such as the TDT log and the initial openhole logs, to compare actual performance with indicated reservoir potential. performance with indicated reservoir potential. The analysis of producing wells is rarely simple. Downhole flow usually involves different fluids (oil, water, and gas) having different densities and moving at different velocities. Furthermore, these may vary with time because of well instability. Typically, several measurements are needed to resolve the problem. The effect of well instability can be reduced problem. The effect of well instability can be reduced by obtaining the measurements simultaneously. Much has been published in the literature on the use of flowmeter, thermometer, manometer, Gradiomanometer TM and caliper tools to analyze downhole flow. In addition, a casing-collar locator and a gamma-ray log are useful for depth control and correlation with the formation evaluation logs.In this paper we describe a new 1 11/16-in. (42.9-mm) diameter telemetry-based tool - the PLT (TM) (simultaneous production logging tool) - capable of transmitting all these measurements simultaneously during one trip in the well. It is relatively easy to add new sensors to this flexible system. A new dual tracer ejector tool and a high-precision pressure gauge, which have been added to the above family of sensors, also are discussed.This paper presents the results of a 15-well logging program in which the PLT tool was used to evaluate program in which the PLT tool was used to evaluate a miscible flood project in the South Swan Hills pool in Alberta, Canada. While tracer materials were used to monitor the lateral progress of the flood front, production logging was used to monitor the vertical production logging was used to monitor the vertical distribution in both injection and production wells. JPT P. 191