Tectonic Evolution of the Delaware-Val Verde Basin, Texas and New Mexico

Elam, Jack G. (Independent Geologist)

OnePetro 

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.

Abstract. The Delaware-Val Verde Basin is a marginal foreland basin genetically related to the Ouachita over-thrust belt and its associated subduction zone. Proximal structures to the overthrust belt evidence compressional folding and faulting indicative of a horizontal maximum principal stress, but the dominant principal stress of the principal stress, but the dominant principal stress of the more distal and productive structures is vertical. A similar tectonic style is evidenced for the Permian Basin as a whole. Isopachs indicate that structural growth began early and continued intermittently throughout the Paleozoic. The largest early structure is found in the Paleozoic. The largest early structure is found in the Puckett field in Pecos County, Texas. It has numerous Puckett field in Pecos County, Texas. It has numerous diameters and/or unconformities in the Ordovician-Silurian-Devonian interval and there was 1500' of closure by the time the Devonian was deposited. Other large structures such as the nearby Gomez field show minor early Paleozoic growth, and early structural trends are not Paleozoic growth, and early structural trends are not always concordant with later vertical uplifts. Maximum instability occurred during the Mississippian, Pennsylvanian and wolfcampian with concurrent uplift of producing structures and subsidence of the intervening grabens. This period of instability is coincident with the period of maximum activity along the Ouachita subduction zone. It is believed that thermal and isostatic activity related to the subduction zone caused this differential vertical uplift and subsidence. The stress system appears to be caused by fluid movements in the crust or subcrust. As lighter material was subduced to mantle depths there was some partial melting and diapiric rise of these lighter materials. The complete process is not fully understood. Rigid basement blocks were tilted and uplifted along basement faults. The overlying sediments behaved plastically and basement faults die out rapidly upwards plastically and basement faults die out rapidly upwards in the section. Faulting is rarely encountered in the bore hole but steep to overturned beds are common. Where minor faulting is encountered in the producing fields, it appears to have served as a conduit for rising hydrothermal fluids which cause some secondary cementation and loss of porosity and permeability. This has caused some well located wells structurally to be dry or non-commercial. The tectonic style of the Delaware-Val Verde basin is similar to that of many other foreland basins throughout the world. The Wyoming province of the Rocky Mountain foreland is a case in point. The largest producing fields in the world, Ghawar in Saudi Arabia, and producing fields in the world, Ghawar in Saudi Arabia, and Burgan in Kuwait, are differentially uplifted structures which occur on the Arabian foreland shelf in front of the Iranian subduction zone. The tectonic style of differential vertical uplift has been poorly understood in the past and, even today, is seldom mentioned in structural geology textbooks. Yet it is a most significant mode of deformation as regards the petroleum industry.