CREDO Petroleum Announces Calliope Successfully Installed on Four New Wells; Depth Record Extended Almost 50% to 18,400 Feet.

Business Editors

DENVER--(BUSINESS WIRE)--May 21, 2003

CREDO Petroleum Corporation (NASDAQ: CRED) today updated results of recent installations of its patented Calliope Gas Recovery System.

James T. Huffman, President, said: "We have installed Calliope on four of the nine candidate wells acquired late last year. Previous owners gave up on the wells and all but one had been completely dead for at least a year. All of the installations were successful in adding significant, long-lived reserves and immediately restoring production rates to levels that will provide excellent rates of return on our investment".

CALLIOPE DEPTH RECORD EXTENDED ALMOST 50% TO 18,400 FEET

Calliope's operating depth range was substantially extended with a successful installation on the 18,400-foot Green Estate well located in Beckham County, Oklahoma. Calliope's previous record depth was 12,500 feet. The Green Estate well had produced 28.8 Bcfg and, at the time Calliope was installed, had been dead for three years. Testing and well data indicated that significant reservoir damage was caused by a workover performed by the previous owner. Although the company expected Calliope production to be compromised, it proceeded with the installation in anticipation of strong gas prices and the well's high reserve potential.

Calliope immediately restored daily production to over 300 Mcfg (thousand cubic feet of gas) and five to seven barrels of condensate and water. Installation cost was approximately $400,000. Reservoir pressure indicates that up to 2.0 Bcfg (billion cubic feet of gas) of remaining gas reserves could be recovered by Calliope (8/8ths basis). At current gas prices, the total value of these reserves would be $12,000,000, before pipelining costs and regional gas price basis differentials. CREDO owns a 65% working interest in the well and is the operator.

"Calliope has been more flexible that originally expected and we have proven it will work successfully over a broad range of wellbore conditions, including wells with packers and tubing diameters of less that 2.0-inches," Huffman said. "Now we have extended Calliope's operating depth range by almost 50% and have established its viability in a rigorous deep well application. This is a very important accomplishment because installation and operating complexity increases exponentially as we move into significantly deeper reservoirs."

CALLIOPE SUCCESSFULLY INSTALLED ON THREE ADDITIONAL WELLS

Calliope was also recently installed on the 12,300-foot Meacham well located in Custer County, Oklahoma. The well had produced 20.0 Bcfg and 322,000 barrels of oil and was flowing at marginal rates before the installation. During the installation a perforating gun was lost in the hole resulting in a compromised installation. Nevertheless, Calliope increased daily production to 150 Mcfg and two barrels of condensate and water. The cost to install Calliope was approximately $350,000 and it is expected to add about 1.0 Bcfg to gross recoverable reserves. At current gas prices, the reserves have a total value of about $6,000,000 before pipelining costs and basis differentials. CREDO owns an approximate 80% working interest and is the operator.

As previously announced, in mid-February Calliope was installed on the 11,100-foot Fee well located in Hemphill County, Texas. The well had produced 8.0 Bcfg and had been dead for about a year. Calliope immediately restored daily production to 250 Mcfg and six barrels of condensate and it has since remained at that level. The installation cost about $150,000 and the company estimates that Calliope added approximately 500 MMcfg (million cubic feet of gas) to gross recoverable reserves. At current gas prices, the reserves have a total value of about $3,000,000 before pipelining costs and basis differentials. CREDO owns an approximate 78% working interest and is the operator.

Also as previously reported, in early March Calliope was installed on the 12,400-foot Horn well located in Grady County, Oklahoma. The well had produced 12.9 Bcfg and had been dead for three years. Prior to being shut-in, the well apparently experienced a packer leak and soap was used to stimulate production, both of which compromised the permeability of the reservoir. Nevertheless, Calliope immediately restored daily production to approximately 180 Mcfg and it has since remained at that level. The installation cost about $280,000. Reservoir pressure indicates that up to 1.0 Bcfg of remaining reserves could be recovered by Calliope (8/8ths basis). At current gas prices, the total value of these reserves would be $6,000,000, before gas pipelining costs and basis differentials. CREDO owns a 78% working interest in the well and is the operator.

MANAGEMENT COMMENT

"We are very pleased with 100% success on these four installations and to have proven that Calliope will work efficiently at extreme depths," Huffman said. "We face many perils in older wells such as unforeseeable down-hole mechanical problems and reservoir damage caused by the `parting shots' of previous owners. However, Calliope continues to be more flexible and more reliable than originally expected. As a result, we have proven that Calliope can be installed profitably over a wide range of applications."

Huffman further stated: "We are moving forward with additional installations on the remaining five wells. Compressors and other equipment have been ordered for three new installations, the first of which is expected to commence in the next six to eight weeks."

CREDO Petroleum Corporation is a publicly traded independent energy company headquartered in Denver, Colorado. The company is engaged in the exploration for and the acquisition, development and marketing of natural gas and crude oil in the Mid-Continent and Rocky Mountain regions. The company's stock is traded on the NASDAQ System under the symbol "CRED" and is quoted daily in the "NASDAQ Small-Cap Issues" section of The Wall Street Journal.

This press release includes certain statements that may be deemed to be "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements included in this press release, other than statements of historical facts, address matters that the company reasonably expects, believes or anticipates will or may occur in the future. Such statements are subject to various assumptions, risks and uncertainties, many of which are beyond the control of the company. Investors are cautioned that any such statements are not guarantees of future performance and that actual results or developments may differ materially from those described in the forward-looking statements.