A New Fracture Gradient Prediction Technique That Shows Good Results in Gulf of Guinea

Abstract

One of the major challenges of drilling and completion of oil and gas wells is the uncertainty in the formation fracture gradient and the fracture pressure. It is not uncommon that many drilling companies have spent money, resources and time in drilling and completing wells that should have been simply and optimally done. Fracture gradient evaluation constitutes one of the essential parameters in the pre-design stage of drilling operations, reservoir exploitations and stimulations. Several calculation methods and computer models have been presented in the literature for different regions of the world. Most of these techniques were based on either parametric or empirical correlations, which required a prior knowledge of the functional forms or the use of empirical charts which were not very accurate. This paper presents an innovative method of predicting formation fracture gradient for Gulf of Guinea region. A combination of "Mathew and Kelly" correlation, "Hubbert and Willis" correlation and Ben Eaton mathematical models were used in developing the simplified technique based on field data from the Gulf of Guinea. The model compared favorably with the existing fracture gradient results in the Gulf of Guinea with less than 1 % deviation from other correlations thereby saving the rigors and time in using tables, charts and other long techniques. Although the method was developed specifically for the Gulf of Guinea, it should be reliable for other similar areas provided that the variables reflect the conditions in the specific area being considered.

Determining the drilling mud window by integration of geostatistics, intelligent, and conditional programming models in an Oilfield of SW Iran

“…They assumed that the minimum injection pressure to hold open and extend a fracture is equal to the minimum stress. Later on, many empirical and theoretical Equations and applications for fracture gradient prediction were presented (Aadnoy and Larsen 1989;Althaus 1975;Anderson et al 1973;Breckels and van Eekelen 1982;Constant and Bourgoyne 1988;Daines 1982;Eaton 1969;Fredrich et al 2007;Haimson and Fairhurst 1967;Keaney et al 2010;Matthews and Kelly 1967;Oriji and Ogbonna 2012;Pilkington 1978;Saadatnia et al 2022;Wessling et al 2009;Zhang 2011;Zhang et al 2022). In this study some commonly used methods are described in the following sections.…”

Determining the drilling mud window by integration of geostatistics, intelligent, and conditional programming models in an oilfield of SW Iran

“…They assumed that the minimum injection pressure to hold open and extend a fracture is equal to the minimum stress. Later on, many empirical and theoretical equations and applications for fracture gradient prediction were presented (Aadnoy and Larsen 1989;Althaus 1975;Anderson et al 1973;Breckels and van Eekelen 1982;Constant and Bourgoyne 1988;Daines 1982;Eaton 1969;Fredrich et al 2007;Haimson and Fairhurst 1967;Keaney et al 2010;Matthews and Kelly 1967;Oriji and Ogbonna 2012;Pilkington 1978;Saadatnia et al 2022;Wessling et al 2009;Zhang 2011;Zhang et al 2022).…”