Development of Mathers Ranch Field, Drilling and Completion
Authors: Alexander B.G. , Sarles H.L. 
Published: December 2007

This paper was prepared for the 1972 Deep Drilling Symposium of the Society of Petroleum Engineers of AIME to be held in Amarillo, Tex., Sept. 11–12, 1972. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon requested to the Editor of the appropriate journal, provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

The Mathers Ranch (Hunton) Field was discovered in March, 1970. It has offered the industry many challenges in drilling and completing 17,500 foot gas wells. Much has been learned and with the help of all interested parties concerned with this area, much will be learned in the future.

Introduction

The Mathers Ranch (Hunton) Field was discovered by McCulloch Oil Corporation in March, 1970, with production from the Mathers Ranch No. 1, Sec. 1518, J. Flowers Survey, Hemphill County, Texas. Since this discovery, there have been 14 Hunton wells drilled and completed and there are currently five wells in various stages of drilling and completion. Figure 1. Production is from the Hunton Reservoir at a Production is from the Hunton Reservoir at a depth of 17,500 feet. The Hunton in this area is a lime and dolomite section that varies from 150–250 feet thick with production coming from porosity in the bottom production coming from porosity in the bottom 40–50 feet of the reservoir.

Drilling Program

During development of the Mathers Ranch, much has been learned about drilling mechanics, pipe programs and drilling fluids that have cut costs from $44.65 per foot to $35.71 per foot. Table 1. Figure 2. per foot. Table 1. Figure 2.Continuous improvement in bit selection, along with rotary speed and bit weight programs, have improved penetration rates due programs, have improved penetration rates due to less trip time. The biggest improvement has been in the lime sections such as the Brown Dolomite, Chester and Mississippian Meramec-Osage. Journal bearing bits, J-33, J-44, J-55, J-88, have consistently averaged 80–110 rotating hours depending upon the bit weight and rotary speed, and the amount of chert present in the samples.

Pipe programs have changed considerably depending on the presence of abnormally pressured Morrow sands. In drilling on the pressured Morrow sands. In drilling on the west side of the field, we normally use a program of 1000'-20"; 4200'-13-3/8"; program of 1000'-20"; 4200'-13-3/8"; 11,300'-9-5/8"; 7-5/8" liner-14,000'; 5-1/2"-13,500' with 4-1/2"-13,500' to TD. This program is designed to insure that abnormal pressures (BHP 6500 psi) in the Morrow can be controlled by casing off the low pressure Penn.