Big Sand Draw Field – The Proof is in the Details
Christopher E. Mullen, Wold Oil
Properties, 139 West Second Street, Suite 200, Casper, WY 82601, phone: 307 265-7252, fax: 307 265-7336, [email protected]
The Tensleep production at Big
Sand Draw Field, Fremont County,
Wyoming, was initiated in 1944.
The Tensleep produces 33.6 gravity
crude from an average depth of 7500 feet. The average pay thickness is
278 feet, with an average porosity of 2.6%. Since that time more than 54
million barrels of oil has been produced from this reservoir. The Tensleep has seen three distinct phases of development. The
first phase took place in the late 1940's to early 1950's. The second phase
occurred in the middle 1960's when many of the existing Phosphoria
producers were deepened to the thicker, more prolific Tensleep
sandstone. The third phase took place in 1972, six
additional wells were drill to the Tensleep at this
time. Before the drilling of the 1972 program, 43 million barrels of oil had
been produced, approximately 79% of the total cumulative production. By
studying the location and production histories of these 6 wells three important
facts come to light. First, the six wells added 3,300 barrels of oil per day to
the field production. Second, two of the six wells had initial production rates
in the 2000 barrels of oil per day range. The six wells exhibited higher oil
cuts than surrounding wells, indicating the potential for banked oil left in
the field. Based on an integrated geologic and reservoir model of the Tensleep at Big Sand Draw it has been determined that there
is considerable reserve potential remaining in this 60 year old field.