Abstract: Comparison of MWD and Wireline Applications and Decision Criteria, Malay Basin

Kushairi Zainun, Mohd. Redzuan Mohd. Said, Tan Kai Soon

Since 1987, usage of measurement while drilling (MWD) technology within Esso Production Malaysia Inc. (EPMI) has evolved from an auxiliary directional drilling service to providing a reliable alternative to wireline logs for formation evaluation and well-completion purposes. The shift in EPMI's attitude toward the use of MWD in formation evaluation is attributed to the availability of a complete suite of logging services for our log analysis procedure, accuracy of the data, sufficient control in reservoir quality, and continuity in fields where there are already a high density of wireline-logged wells, increasing number of high angle and horizontal wells being drilled, a favorable track record, and realized economic benefits.

Our in-house log analysis procedure, (EPMILOG⁶), requires the availability of a deep and/or shallow investigating resistivity, formation density, neutron porosity, and gamma ray tools for a complete analysis. The availability of these services in MWD and also comparative evaluations of MWD responses with their correlative wireline

counterparts show that MWD technology can be used, to a large extent, to complement or replace routine wireline logging services.

MWD resistivity measurements are frequently observed to be less affected by mud filtrate invasion than the correlative wireline measurements and are, therefore, closer to the true resistivity of the formation. MWD formation evaluation services are most widely used in fields where there are already a high density of wells that were logged using wireline. The MWD data is used to decide perforation depths and intervals.

The number of horizontal and highly deviated wells in the Malay Basin being planned and drilled are increasing and MWD logs have provided an economic alternative to the risky, time consuming wireline logging via drill pipe. The use of MWD has realized dollar savings in rig time and invoicing of about US $30K over normal wireline and US $170K over logging via drill pipe.

AAPG Search and Discovery Article #90982©1994 AAPG International Conference and Exhibition, Kuala Lumpur, Malaysia, August 21-24, 1994