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PublisherWorld Petroleum CongressLanguageEnglish
Document ID 12276
Content TypeConference Paper
TitleRepressuring of the Masjid-I-Sulaiman Oilfield from a Deep Underground Jurassic Gas Leak and Remedial Killing Operations
AuthorsN. Baniriah, G. C. Beckman, J. Birks,(Iranian Oil Exploration and Producing Company, Iran)
Source7th World Petroleum Congress, April 2 - 9, 1967 , Mexico City, Mexico
Copyright1967. World Petroleum Congress
Preview REPRESSURING OF THE MASJID-I-SULAIMAN OILFIELD FROM A DEEP UNDERGROUND JURASSIC GAS LEAK AND REMEDIAL KILLING OPERATIONS

INTRODUCTION

gas cap-the structure was originally full of oil-and a relatively small volume of water encroachment. The Since April 1964, the shallow oil reservoirs of Iran's original oil column of 2,500 feet at the crest has been Masjid-i-Sulaiman (MIS) Field have been in com- depleted to a present thickness of 140-400 feet. Current munication with a deep, high pressure, sour gas production averages 55,000 B/D from 25 wells and an reservoir via the wellbore of deep test MIS-306. As of average of 21,000 BID of topping plant distillate is November 1, 1966, approximately 305 billion cubic being returned to the Asmari. The field is considered to feet of gas have been transferred to the shallow reser- be 85% depleted. voirs. The cause and effects of this involuntary re- pressuring and related remedial work form an interest- ing case study which, in many respects, is unique in the EVENTS AT MIS-306 LEADING TO THE history of oil exploitation and production. UNDERGROUND BLOW-OUT MIS-306 was drilled for the purpose of exploring the THE RESERVOIR prospects for production in deeper formations hereto- fore untested in the northern portion of the Iranian Masjid-i-Sulaiman Field, the first oil discovery in Consortium's Agreement Area. The major targets the Middle East (1908), is located in the foothills of were the Lower Cretaceous, Jurassic, Triassic, and the Zagros Mountains near the northern limits of the Paleozoic Sediments. After encountering a thrust fault Iranian Oil Exploration & Producing Company's at 14,680 feet followed by a repeated section of the current producing area. As in nearly all other fields of Middle Jurassic, it was concluded that the two deeper South Iran, the major oil accumulation is encountered objectives could not be reached in this well. Drilling was in the prolific Asmari limestone (Oligo-Miocene) stopped at a total depth of 15,003 feet with well con- on an anticlinal structure. Oil production has also been ditions as follows: encountered at a single location in the underlying 2 0 casing was cemented in the Asmari cap Eocene limestone. The field is about 18 miles long and rock 1,599' 3-5 miles wide with a productive area of 28,400 acres. 13 318" casing was cemented in the base of The crest of the Asmari is only 600 feet below ground the Eocene 3,881' level in some areas and the average depth of the 9 518" casing was cemented in the Lower reservoir is less than 2,000 feet. Cretaceous shale 1 1,050' The Asmari is a massive dolomitic limestone with an 3,953' of open hole from 11,050' to 15,003' T.D. average thickness of about 1,000 feet, 30 % of which is considered to be productive. It is characteristically Drilling performance, sample analysis and coring tight, but highly fractured in the better producing results all indicated that no significant hydrocarbon areas and
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