Logging under Harsh Conditions with New Shuttle-Deployed Memory Tools and Impact on Log Quality, Time and Costs

Abstract

Operational conditions in certain fields can cause various difficulties during logging operations. When such situations occur, we usually opt for logging-while-drilling (LWD) tools. In this paper, we present field applications and advantages of a new generation of tools called shuttle-deployed memory (SDM) tools. Because they can operate under critical borehole conditions and highly deviated wells, SDM tools offer a viable alternative to LWD. We successfully applied this technology to acquire well-log data in two fields of clastic and carbonate reservoirs in the Barinas-Apure Basin, Southwest Venezuela. In this area, conditioning the hole is a required procedure before running logging tools; therefore, the logging system's capacity to get information while conditioning the borehole favored its application when logging under harsh conditions. We show three cases considering wells with angle of deviation up to 40º, dog leg severity up to 4º/100 ft, and several washout and unsteady zones. A comparison with resistivity measurements obtained using an LWD tool is also included in one of the cases, illustrating remarkable improvements in log quality. We also used the acquired information as an input for petrophysical assessment. The results satisfactorily compared against neighbor wells with data obtained from conventional wireline logging tools and rock-core measurements. Likewise, a detailed analysis of time and cost describes the impact of the application of this type of technology on operations in Guafita and La Victoria Fields in Venezuela. We conclusively found that the application of SDM tools for formation evaluation data acquisition reduces logging time by 62% and logging costs up to 44% in these fields. In addition, we obtained reliable well-log information with significant improvements in log quality. More important, the application of SDM tools allowed us to bypass the limitations in terms of variety and quantity for logs that were commonly acquired with LWD tools.

A Systematic Analysis to Select an Optimized Perforating Interval as a Key Factor for Improved Oil Recovery: Impact of Dynamic and Static Petrophysical Properties on Well Production

“…2 shows a stratigraphic column of the Apure area illustrating the vertical location of the intervals of interest. Oil-producing formations belong to the Guafita (Tertiary), Navay (Cretaceous) and Escandalosa (Cretaceous) formations (González de Juana et al, 1980;Miranda and Angel, 2010), according to the stratigraphic column for the reservoirs of these fields located in Barinas-Apure Basin.…”

“…Dispersed clays content within the sandstone reservoirs are mainly a mixture of Caolinite, Illite and Smectite, whose swelling characteristics represent a problem when drilling with water-based muds (Miranda and Angel, 2010). In addition, the continuous presence of very thin shale beds (laminar clay) within these reservoirs is a continuously concerning issue when running resistivity or induction tools since these clays tend to lower down the measured resistivity, which yields to an under-estimation in reserves.…”

“…However, thick intervals constituted of tertiary swelling clays, along with the active geomechanical forces within the area, have induced in several opportunities the sticking of the drillpipe or the wireline logging tools resulting in the lost of the borehole in the worst of the cases (Miranda and Angel, 2010). In addition, the no-possibility of drill vertical wells in most cases and the amount of drilled wells so far, are a restriction in designing locations trajectory, with increasing difficulties every year.…”