Formation Pressure-Production Relationship Lake Mongoulois Field

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. This paper was prepared for the 43rd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Sept. 29-Oct. 2, 1968. 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 request 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 discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Lake Mongoulois dome in central St. Martin Parish of Louisiana, lies within the Upper Parish of Louisiana, lies within the Upper Oligocene trend and produces from two main pay zones. Structure and sand development pay zones. Structure and sand development are similar on all flanks of the dome. The distribution of hydrocarbons appears to be directly related to the pressure environments in the area. Calculated formation pressures indicate that the productive zones lie within the pressure minima flanks of the dome. Introduction Formation pressures and their relationship to production remain common topics for discussion production remain common topics for discussion among explorationists. Production has been found in pressure environments ranging from hydrostatic to about 90% of geostatic pressure. In the Lake Mongoulois Field, the pressure. In the Lake Mongoulois Field, the distribution of hydrocarbons appears to be directly related to the pressure environments in the area. REGIONAL SETTING Lake Mongoulois Field is located in St. Martin Parish of central Louisiana (Fig. 1). It lies along the southern edge of the Oligocene production trend that strikes northeast-southwest from the field. The field is associated with several salt domes in the area and lies along a north-south salt ridging that connects with Bayou Bouillon Field to the north (Fig. 2). The Lake Mongoulois structure is formed by a small salt dome, topped at -6920' in a crestal well (Fig. 3). Salt has been penetrated in only six of the 68 wells drilled in the area. The dome appears to be conical and spreads to about 1-1/2 miles in diameter at 10,000'. The subsurface structure suggests a westward salt nosing with depth but no salt control or seismic is available for substantiation. STRATIGRAPHY AND STRUCTURE The regional stratigraphy is represented by the log on an east flank well numbered 1 on Fig. 3. This well encountered multiple sands to the base of the Miocene at 10,600', sparse somewhat limey sands to 12,500', and deepwater marine shales to its total depth of 15,400' (Fig. 4). The bottom 1700' of log is omitted on this figure. The main pay zones are in the Marginulina and Miogypsinoides horizons that overlie the Hackberry shale sequence. These reservoir sands are generally uniformly developed on all flanks of the dome.