East Texas Deep Bossier gas deliveries expanding

April 16, 2007
The East Texas Deep Bossier gas play is growing fast with some of the country’s highest-delivering wells and a lot of room to grow.

The East Texas Deep Bossier gas play is growing fast with some of the country’s highest-delivering wells and a lot of room to grow.

Dry gas production from the Amoruso area alone topped 200 MMcfd in early April 2007, having doubled since February 2007 due to the hookup of several high-rate wells. The Robertson County area’s production rate could double again before the end of 2007, one participant said.

Amoruso is considered one of the five largest US onshore discoveries in the past decade.

While drilling to the Bossier at 14,000-18,000 ft, operators have seen good potential in shallower pay zones that have yielded good recoveries throughout the East Texas basin. These include the Upper Cretaceous Austin chalk and Woodbine, Lower Cretaceous Georgetown, Rodessa, James, Pettit, and Travis Peak, and Upper Jurassic Cotton Valley.

Operators expect to ultimately recover several trillion cubic feet of gas from the area, but it is too early to be precise about the total.

Amoruso prospect

EnCana Oil & Gas (USA) Inc. has operated all but one of the wells drilled so far at Amoruso, namesake of geologist John J. Amoruso, under its 50-50 agreement with Leor Energy LP, private Houston independent (OGJ, Oct. 23, 2006, p. 20).

An application has been filed for official designation as Amoruso field.

Leor Energy operated the discovery well, McCullough-1, completed and placed on production in late 2005. The companies had 19 wells producing in early April, several more were to go on line through mid-June, and eight rigs were running.

A well to 16,000 ft takes 75-80 days at an average $8 million to drill and complete. Crews face hard drilling in complex geology and pressures of 15,000 psi in the Deep Bossier, said Guma Aguiar, vice-chairman and chief executive officer, Leor Energy.

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Initial production rates probably average 10-15 MMcfd, but several of the wells have started out at 45-55 MMcfd, Aguiar said.

In the last 10 years, he said, only 26 US wells have made 1 bcf of gas or more in their first 30 days on production, and three of the top 10 wells are in the Amoruso area. Initial production rate averaged 17 MMcfd at the last 13 wells and 22 MMcfd at the last six wells, Aguiar said.

He expects many wells to yield 80% of their estimated ultimate recovery in 3-5 years and have producing lives of 15-20 years. Leor projects EUR of 2-3 tcf net to its Amoruso area interest excluding development upside.

Initial data are to be delivered in the third quarter from a large 3D seismic survey in Robertson County supported by Deep Bossier operators EnCana, Leor, ConocoPhillips, Gastar Exploration Ltd., and Chesapeake Energy Corp.

The program for the rest of 2007 calls for offsetting some of Amoruso’s best wells, working on 640-acre units. Aguiar estimates that EnCana has drilled only 1-2% of Amoruso’s 55,000 acres.

Other fields

Several other fields are under development in the Deep Bossier and shallower formations.

Chesapeake Energy Corp., Oklahoma City, acquired 16.5% of Gastar and a 33% working interest in Gastar’s 26,000 net acres in Hilltop Resort field, Leon and Robertson counties (OGJ Online, Nov. 15, 2005).

Gastar said its 2006 Deep Bossier reserves increased 86% to 21 bcfe after production of 2.9 bcfe, but the numbers don’t reflect late-2006 successful wells, and gross East Texas gas sales nearly doubled as of Mar. 31 from the end of 2006.

Log analysis showed that Gastar’s Lone Oak Ranch-2 well, TD 18,100 ft in Leon County, cut 36 ft of apparent net pay in two Bossier sands and was being cased at the end of March.

Gastar was drilling the Wagner-1 and Donelson-3 offset wells. Other recent completions were John Parker-2, Williams-1, and Wildman Trust-2. LOR-2 was in completion, and further production growth was expected in the second quarter from 22 MMcfd in mid-March, Gastar said.

ConocoPhillips is working to the north in the Rainbolt Ranch area.

Expanding play

EnCana and Leor are in early drilling stages of another project farther east.

Project Houston, aimed at Deep Bossier gas and the same bailout zones as in Robertson County, takes in 100,000 gross acres in Angelina, Houston, Nacogdoches, and Trinity counties.

The first well there was disappointing, but the second well has raised high expectations, Aguiar said.